3–7 days — snow level and model spread

Snow level against each resort’s terrain, with precipitation phase at the selected lifted elevation.

Experimental 1500 m SWE map Nine discrete ECMWF IFS samples · three-hour frames · wet-bulb phase · no interpolation
Show NSW VIC

Forecast view

Applies to the snow-level charts and precipitation phase below.

Below model terrain
Phase elevation
Primary precipitation
Add comparison tracks
Local-resolution reference
Grid styles are a fixed print look — palette and dark mode do not apply inside them.
Models shown
Why ACCESS-G point values are unavailable

ACCESS-G is running, but its free point-data relay is not. Current Bureau rainfall, pressure, 850 hPa temperature and humidity remain available in the ACCESS-G map viewer.

All-resorts model precipitation · Mid lifted elevation

Sun 2 Aug 10:00 → Sun 9 Aug 09:00 AEST — same window for every model below

Snow-phase / total precipitation at each resort’s Mid lifted elevation, in mm liquid equivalent. Snow-phase colour follows amount; total uses an amount-weighted grey scale. Bars are scaled within each model column: their length shows amount, while coloured snow-phase plus the grey non-snow remainder shows phase. 035+ mm
Resort ECMWF IFS ECMWF AIFS GFS ICON
Perisher 1824 m 1.4 / 8.6 0.6 / 2.8 15.2 / 15.3 13 / 13
Thredbo 1701 m 14.7 / 25.4 5.4 / 13.1 11 / 11 4.8 / 9.7
Charlotte Pass 1860 m 21.9 / 25.4 6.2 / 13.1 15.2 / 15.3 13 / 13
Selwyn 1553 m 4.5 / 10.6 3 / 10.6 9.6 / 10.7 2.9 / 10.3
Mt Hotham 1648 m 7.6 / 17.6 5.3 / 13.2 23.8 / 25.4 1.2 / 13
Falls Creek 1640 m 13.9 / 30.3 7.5 / 20.5 23.3 / 25 4.5 / 20.7
Mt Buller 1578 m 12.9 / 25.9 6.9 / 18.3 27.1 / 29.5 6.7 / 28.4
Mt Baw Baw 1507 m 6.3 / 30.1 1.8 / 17.9 9 / 31.6 1.8 / 10.5
All-resorts daily forecast precipitation

Daily values are AEST, in mm liquid equivalent. The final column is each forecast’s full-window sum. Forecast rows follow the selected primary/comparison models. The local 9 km reference follows the ECMWF IFS selection, with unphased precipitation and native SWE shown separately. For a longer selectable period, open the model explorer.

Resort Forecast Sun 2Mon 3Tue 4Wed 5Thu 6Fri 7Sat 8Sun 9 Total
Perisher ECMWF IFS 01.20.60000.36.5 8.6
Perisher ECMWF AIFS 0000.6000.22 2.8
Perisher GFS 006.76.700.101.8 15.3
Perisher ICON 003.63.30006.1 13
Perisher IFS 9 km surface · unphased precip 00.54.13.5000.611.5 20.2
Perisher IFS 9 km surface · native SWE 00.13.71.5000.610 15.9
Thredbo ECMWF IFS 01.84.63.8000.714.5 25.4
Thredbo ECMWF AIFS 0.11.82.42.9000.45.5 13.1
Thredbo GFS 005.24.80001 11
Thredbo ICON 00.21.91.50006.1 9.7
Thredbo IFS 9 km surface · unphased precip 00.71.60.8000.511 14.6
Thredbo IFS 9 km surface · native SWE 00.31.80.4000.510 13
Charlotte Pass ECMWF IFS 01.84.63.8000.714.5 25.4
Charlotte Pass ECMWF AIFS 0.11.82.42.9000.45.5 13.1
Charlotte Pass GFS 006.76.700.101.8 15.3
Charlotte Pass ICON 003.63.30006.1 13
Charlotte Pass IFS 9 km surface · unphased precip 01.39.810.1000.915.5 37.6
Charlotte Pass IFS 9 km surface · native SWE 00.68.65.2000.913 28.3
Selwyn ECMWF IFS 00.313.5000.35.5 10.6
Selwyn ECMWF AIFS 0.11.11.31.7000.46 10.6
Selwyn GFS 0.205.23.50001.8 10.7
Selwyn ICON 0030.20007.1 10.3
Selwyn IFS 9 km surface · unphased precip 00.72.43.9000.49 16.4
Selwyn IFS 9 km surface · native SWE 001.91.3000.46 9.6
Mt Hotham ECMWF IFS 00.72.10.5000.813.5 17.6
Mt Hotham ECMWF AIFS 0.21.82.92.3000.55.5 13.2
Mt Hotham GFS 0.52.77.980006.3 25.4
Mt Hotham ICON 00.10.80.300.30.311.2 13
Mt Hotham IFS 9 km surface · unphased precip 01.35.65.8001.919 33.6
Mt Hotham IFS 9 km surface · native SWE 00.73.81.7001.815.5 23.5
Falls Creek ECMWF IFS 0.11.94.73.30.502.317.5 30.3
Falls Creek ECMWF AIFS 0.233.62.8001.49.5 20.5
Falls Creek GFS 0.61.38.57.20007.4 25
Falls Creek ICON 001.40.8000.318.2 20.7
Falls Creek IFS 9 km surface · unphased precip 002.73.5001.518 25.7
Falls Creek IFS 9 km surface · native SWE 002.41.3001.517.5 22.7
Mt Buller ECMWF IFS 0.13.45.62.10.202.512 25.9
Mt Buller ECMWF AIFS 0.11.94.72.3001.38 18.3
Mt Buller GFS 0.14.513.53.50007.9 29.5
Mt Buller ICON 02.34.91001.418.8 28.4
Mt Buller IFS 9 km surface · unphased precip 04.17.85.60.602.814 34.9
Mt Buller IFS 9 km surface · native SWE 001.20.4000.13.5 5.2
Mt Baw Baw ECMWF IFS 02.87.58.7201.67.5 30.1
Mt Baw Baw ECMWF AIFS 01.35.55.2000.95 17.9
Mt Baw Baw GFS 01.111.116.60.70.102 31.6
Mt Baw Baw ICON 01.13.60.8000.24.8 10.5
Mt Baw Baw IFS 9 km surface · unphased precip 00.96.19.4100.96.5 24.8
Mt Baw Baw IFS 9 km surface · native SWE 000.500000.5 1

Perisher NSW · 1605–2042 m

Snow level and precipitation

ECMWF IFS · Mid · 1824 m 8.6 mm total 1.4 mm snow 7.2 mm uncertain 0 mm rain 2.5 mm model-grid SWE
ECMWF IFS · Mid · 1824 m 8.6 mm total 1.4 mm snow 7.2 mm uncertain 0 mm rain 2.5 mm model-grid SWE
ECMWF AIFS · Mid · 1824 m 2.8 mm total 0.6 mm snow 2.2 mm uncertain 0 mm rain
ECMWF AIFS · Mid · 1824 m 2.8 mm total 0.6 mm snow 2.2 mm uncertain 0 mm rain
GFS · Mid · 1824 m 15.3 mm total 15.2 mm snow 0.1 mm uncertain 0 mm rain
GFS · Mid · 1824 m 15.3 mm total 15.2 mm snow 0.1 mm uncertain 0 mm rain
ICON · Mid · 1824 m 13 mm total 13 mm snow 0 mm uncertain 0 mm rain
ICON · Mid · 1824 m 13 mm total 13 mm snow 0 mm uncertain 0 mm rain
UKMO Global · Mid · 1824 m 29 mm total 21.7 mm snow 6.6 mm uncertain 0.7 mm rain
UKMO Global · Mid · 1824 m 29 mm total 21.7 mm snow 6.6 mm uncertain 0.7 mm rain
JMA GSM · Mid · 1824 m 0.6 mm total 0.6 mm snow 0 mm uncertain 0 mm rain
JMA GSM · Mid · 1824 m 0.6 mm total 0.6 mm snow 0 mm uncertain 0 mm rain
Models · toggle
Estimated snow level by model in metres above sea level, with selectable model precipitation beneath on the same time axis Wet-bulb-derived snow level from ECMWF IFS, ECMWF AIFS, GFS, ICON, plotted against the resort's elevation range. UKMO Global and JMA GSM are also plotted but hidden until switched on with the model legend above. Estimate mode continues sub-zero surface hours below model terrain using a lapse-rate estimate. Terrain upper bound mode stops those hours at the model terrain and leaves phase beneath unresolved. Precipitation colours and totals are evaluated at Mid · 1824 m. The selected precipitation model receives the strongest line emphasis; other models receive medium emphasis where their own precipitation is falling. The histogram beneath follows the page's selected precipitation model. Estimated snow level · metres AMSL Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 500 1000 1500 2000 base 1605 m top 2042 m Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1500 2000 base 1605 m top 2042 m 0 0.5 1.0 mm/h ECMWF IFS precipitation · phase at Mid · 1824 m 8.6 mm total 0 0.3 0.5 mm/h ECMWF AIFS precipitation · phase at Mid · 1824 m 2.8 mm total 0 0.9 1.8 mm/h GFS precipitation · phase at Mid · 1824 m 15.3 mm total 0 0.8 1.7 mm/h ICON precipitation · phase at Mid · 1824 m 13 mm total 0 0.7 1.4 mm/h UKMO Global precipitation · phase at Mid · 1824 m 29 mm total 0 0.3 0.5 mm/h JMA GSM precipitation · phase at Mid · 1824 m 0.6 mm total
ECMWF IFS 8.6 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.0 0 ECMWF AIFS 2.8 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.5 0 GFS 15.3 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.8 0 ICON 13 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.7 0 UKMO Global 29 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.4 0 JMA GSM 0.6 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.5 0 IFS 9 km surface; sampled -36.380, 148.435; model terrain 1621 m; Sun 2 1600hrs AEST · 0600Z IFS 9 km surface · unphased local reference 20.2 mm precip 15.9 mm native SWE Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.7 0
snow uncertain rain 9 km reference · unphased
Snow-level method · experimental
ECMWF IFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1353 m; resolved between 850 hPa and 700 hPa, 1557 m apart; 73 h estimated below model terrain at 6.5 °C/km
ECMWF AIFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1353 m; resolved between 850 hPa and 700 hPa, 1553 m apart; 20 h estimated below model terrain at 6.5 °C/km
GFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1353 m; lapse-estimated 209 m below the model surface; 121 h estimated below model terrain at 6.5 °C/km
ICON
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1353 m; lapse-estimated 1 m below the model surface; 114 h estimated below model terrain at 6.5 °C/km
UKMO Global
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1353 m; resolved between 850 hPa and 800 hPa, 487 m apart; 111 h estimated below model terrain at 6.5 °C/km
JMA GSM
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1353 m; resolved between surface and 850 hPa, 147 m apart; 39 h estimated below model terrain at 6.5 °C/km
ECMWF IFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ECMWF AIFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
GFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ICON
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
UKMO Global
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
JMA GSM
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound

Where the wet-bulb is already below zero at a model’s grid terrain, the continuous line extends downward using a 6.5 °C/km environmental lapse-rate estimate, with the uncertainty band widened across a 4.5–8.5 °C/km range. It is useful below-terrain guidance, not a model level directly resolved there.

Dashed sections stop at the model’s grid terrain. They are upper bounds: the wet-bulb zero is somewhere at or below that height, but this view does not estimate how far below. Phase below the bound remains uncertain.

The shaded band is a heuristic uncertainty around ECMWF IFS’s snow level. Each coloured snow-level line is emphasised where that model forecasts precipitation. The selected precipitation model receives the strongest emphasis because it also supplies the primary histogram and headline; other wet model lines remain medium-weight. Phase colours and totals here are judged at Mid · 1824 m.

Model-grid SWE is ECMWF IFS’s native sf field (parameter 144), expressed as liquid water equivalent at the model grid cell and its terrain. It is shown as an independent comparison: it does not alter the resort-elevation wet-bulb phase analysis and is not a settled-snow depth.

IFS 9 km surface is a separate native-resolution deterministic IFS surface sample. Its precipitation bars are intentionally unphased: this feed does not supply the pressure-level temperature/humidity profile used by the snow-level method. Native SWE is shown independently and does not alter the 25 km profile or ensemble products. Sampled cell -36.380, 148.435 · model terrain 1621 m · Sun 2 1600hrs AEST · 0600Z.

Model run Sun 2 1000hrs AEST · 0000Z · 13 h ago · fetched 1 min ago

Calculation method

Snow level is the lowest height at which the model’s own WET-BULB temperature crosses 0 °C — the operational definition NOAA’s National Blend of Models uses. Above that height precipitation reaches the ground as snow; below it, it melts on the way down. The wet-bulb matters rather than the ordinary (dry-bulb) temperature because falling snow is cooled by its own evaporating meltwater: in dry air snow reaches the ground at air temperatures well above freezing, and a dry-bulb rule would call that rain. Wet-bulb is solved from the psychrometric equation at each level’s own pressure — evaporative cooling is stronger in thinner air, so a sea-level formula applied at 700 hPa reads too warm and pushes the snow level too high. The profile uses each model’s pressure-level temperature and humidity (ECMWF publishes 1000/925/850/700/600/500 hPa; GFS and ICON add 950/900/800) and only levels above the model’s own terrain, since lower ones lie inside the mountain. Where the wet-bulb is already below zero at that terrain there is no crossing to locate: the line continues below terrain using a 6.5 °C/km environmental lapse-rate estimate. These sections are lighter than crossings directly resolved between model levels, and their uncertainty spans 4.5–8.5 °C/km. The shaded band is a HEURISTIC uncertainty: assumed temperature errors propagated through the measured lapse rate. Its constants are our estimate, not a published figure, which is why each model’s disclosure also states the actual pressure levels its crossing was resolved between. Precipitation totals are millimetres of LIQUID EQUIVALENT, which is what the models publish — not a settled snow depth. We deliberately do not convert 1000–500 hPa thickness into metres: the textbook 5400 m rule is calibrated for the Northern Hemisphere and was out by more than a kilometre when checked against a real Australian snow event. Background

Weather data by Open-Meteo.com · ECMWF IFS — © ECMWF, licensed CC BY 4.0

Model comparison, run times and meteograms for Perisher → · ACCESS-G currently unavailable

Thredbo NSW · 1365–2037 m

Snow level and precipitation

ECMWF IFS · Mid · 1701 m 25.4 mm total 14.7 mm snow 10.7 mm uncertain 0 mm rain 18.1 mm model-grid SWE
ECMWF IFS · Mid · 1701 m 25.4 mm total 14.7 mm snow 10.7 mm uncertain 0 mm rain 18.1 mm model-grid SWE
ECMWF AIFS · Mid · 1701 m 13.1 mm total 5.4 mm snow 4.9 mm uncertain 2.8 mm rain
ECMWF AIFS · Mid · 1701 m 13.1 mm total 5.4 mm snow 4.9 mm uncertain 2.8 mm rain
GFS · Mid · 1701 m 11 mm total 11 mm snow 0 mm uncertain 0 mm rain
GFS · Mid · 1701 m 11 mm total 11 mm snow 0 mm uncertain 0 mm rain
ICON · Mid · 1701 m 9.7 mm total 4.8 mm snow 4.9 mm uncertain 0 mm rain
ICON · Mid · 1701 m 9.7 mm total 4.8 mm snow 4.9 mm uncertain 0 mm rain
UKMO Global · Mid · 1701 m 17.6 mm total 5 mm snow 10.4 mm uncertain 2.2 mm rain
UKMO Global · Mid · 1701 m 17.6 mm total 5 mm snow 10.4 mm uncertain 2.2 mm rain
JMA GSM · Mid · 1701 m 0.6 mm total 0.5 mm snow 0.1 mm uncertain 0 mm rain
JMA GSM · Mid · 1701 m 0.6 mm total 0.5 mm snow 0.1 mm uncertain 0 mm rain
Models · toggle
Estimated snow level by model in metres above sea level, with selectable model precipitation beneath on the same time axis Wet-bulb-derived snow level from ECMWF IFS, ECMWF AIFS, GFS, ICON, plotted against the resort's elevation range. UKMO Global and JMA GSM are also plotted but hidden until switched on with the model legend above. Estimate mode continues sub-zero surface hours below model terrain using a lapse-rate estimate. Terrain upper bound mode stops those hours at the model terrain and leaves phase beneath unresolved. Precipitation colours and totals are evaluated at Mid · 1701 m. The selected precipitation model receives the strongest line emphasis; other models receive medium emphasis where their own precipitation is falling. The histogram beneath follows the page's selected precipitation model. Estimated snow level · metres AMSL Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 500 1000 1500 2000 base 1365 m top 2037 m Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1500 2000 base 1365 m top 2037 m 0 1.1 2.2 mm/h ECMWF IFS precipitation · phase at Mid · 1701 m 25.4 mm total 0 0.3 0.7 mm/h ECMWF AIFS precipitation · phase at Mid · 1701 m 13.1 mm total 0 0.8 1.5 mm/h GFS precipitation · phase at Mid · 1701 m 11 mm total 0 0.7 1.4 mm/h ICON precipitation · phase at Mid · 1701 m 9.7 mm total 0 0.6 1.2 mm/h UKMO Global precipitation · phase at Mid · 1701 m 17.6 mm total 0 0.3 0.5 mm/h JMA GSM precipitation · phase at Mid · 1701 m 0.6 mm total
ECMWF IFS 25.4 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 2.2 0 ECMWF AIFS 13.1 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.7 0 GFS 11 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.5 0 ICON 9.7 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.4 0 UKMO Global 17.6 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.2 0 JMA GSM 0.6 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.5 0 IFS 9 km surface; sampled -36.520, 148.353; model terrain 1644 m; Sun 2 1600hrs AEST · 0600Z IFS 9 km surface · unphased local reference 14.6 mm precip 13 mm native SWE Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.7 0
snow uncertain rain 9 km reference · unphased
Snow-level method · experimental
ECMWF IFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1466 m; lapse-estimated 40 m below the model surface; 98 h estimated below model terrain at 6.5 °C/km
ECMWF AIFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1466 m; resolved between surface and 700 hPa, 1484 m apart; 39 h estimated below model terrain at 6.5 °C/km
GFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1466 m; lapse-estimated 273 m below the model surface; 117 h estimated below model terrain at 6.5 °C/km
ICON
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1466 m; resolved between surface and 800 hPa, 419 m apart; 90 h estimated below model terrain at 6.5 °C/km
UKMO Global
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1466 m; resolved between 850 hPa and 800 hPa, 487 m apart; 90 h estimated below model terrain at 6.5 °C/km
JMA GSM
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1466 m; resolved between surface and 850 hPa, 34 m apart; 41 h estimated below model terrain at 6.5 °C/km
ECMWF IFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ECMWF AIFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
GFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ICON
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
UKMO Global
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
JMA GSM
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound

Where the wet-bulb is already below zero at a model’s grid terrain, the continuous line extends downward using a 6.5 °C/km environmental lapse-rate estimate, with the uncertainty band widened across a 4.5–8.5 °C/km range. It is useful below-terrain guidance, not a model level directly resolved there.

Dashed sections stop at the model’s grid terrain. They are upper bounds: the wet-bulb zero is somewhere at or below that height, but this view does not estimate how far below. Phase below the bound remains uncertain.

The shaded band is a heuristic uncertainty around ECMWF IFS’s snow level. Each coloured snow-level line is emphasised where that model forecasts precipitation. The selected precipitation model receives the strongest emphasis because it also supplies the primary histogram and headline; other wet model lines remain medium-weight. Phase colours and totals here are judged at Mid · 1701 m.

Model-grid SWE is ECMWF IFS’s native sf field (parameter 144), expressed as liquid water equivalent at the model grid cell and its terrain. It is shown as an independent comparison: it does not alter the resort-elevation wet-bulb phase analysis and is not a settled-snow depth.

IFS 9 km surface is a separate native-resolution deterministic IFS surface sample. Its precipitation bars are intentionally unphased: this feed does not supply the pressure-level temperature/humidity profile used by the snow-level method. Native SWE is shown independently and does not alter the 25 km profile or ensemble products. Sampled cell -36.520, 148.353 · model terrain 1644 m · Sun 2 1600hrs AEST · 0600Z.

Model run Sun 2 1000hrs AEST · 0000Z · 13 h ago · fetched 1 min ago

Calculation method

Snow level is the lowest height at which the model’s own WET-BULB temperature crosses 0 °C — the operational definition NOAA’s National Blend of Models uses. Above that height precipitation reaches the ground as snow; below it, it melts on the way down. The wet-bulb matters rather than the ordinary (dry-bulb) temperature because falling snow is cooled by its own evaporating meltwater: in dry air snow reaches the ground at air temperatures well above freezing, and a dry-bulb rule would call that rain. Wet-bulb is solved from the psychrometric equation at each level’s own pressure — evaporative cooling is stronger in thinner air, so a sea-level formula applied at 700 hPa reads too warm and pushes the snow level too high. The profile uses each model’s pressure-level temperature and humidity (ECMWF publishes 1000/925/850/700/600/500 hPa; GFS and ICON add 950/900/800) and only levels above the model’s own terrain, since lower ones lie inside the mountain. Where the wet-bulb is already below zero at that terrain there is no crossing to locate: the line continues below terrain using a 6.5 °C/km environmental lapse-rate estimate. These sections are lighter than crossings directly resolved between model levels, and their uncertainty spans 4.5–8.5 °C/km. The shaded band is a HEURISTIC uncertainty: assumed temperature errors propagated through the measured lapse rate. Its constants are our estimate, not a published figure, which is why each model’s disclosure also states the actual pressure levels its crossing was resolved between. Precipitation totals are millimetres of LIQUID EQUIVALENT, which is what the models publish — not a settled snow depth. We deliberately do not convert 1000–500 hPa thickness into metres: the textbook 5400 m rule is calibrated for the Northern Hemisphere and was out by more than a kilometre when checked against a real Australian snow event. Background

Weather data by Open-Meteo.com · ECMWF IFS — © ECMWF, licensed CC BY 4.0

Model comparison, run times and meteograms for Thredbo → · ACCESS-G currently unavailable

Charlotte Pass NSW · 1755–1964 m

Snow level and precipitation

ECMWF IFS · Mid · 1860 m 25.4 mm total 21.9 mm snow 3.5 mm uncertain 0 mm rain 18.1 mm model-grid SWE
ECMWF IFS · Mid · 1860 m 25.4 mm total 21.9 mm snow 3.5 mm uncertain 0 mm rain 18.1 mm model-grid SWE
ECMWF AIFS · Mid · 1860 m 13.1 mm total 6.2 mm snow 6.9 mm uncertain 0 mm rain
ECMWF AIFS · Mid · 1860 m 13.1 mm total 6.2 mm snow 6.9 mm uncertain 0 mm rain
GFS · Mid · 1860 m 15.3 mm total 15.2 mm snow 0.1 mm uncertain 0 mm rain
GFS · Mid · 1860 m 15.3 mm total 15.2 mm snow 0.1 mm uncertain 0 mm rain
ICON · Mid · 1860 m 13 mm total 13 mm snow 0 mm uncertain 0 mm rain
ICON · Mid · 1860 m 13 mm total 13 mm snow 0 mm uncertain 0 mm rain
UKMO Global · Mid · 1860 m 17.6 mm total 12.3 mm snow 5.3 mm uncertain 0 mm rain
UKMO Global · Mid · 1860 m 17.6 mm total 12.3 mm snow 5.3 mm uncertain 0 mm rain
JMA GSM · Mid · 1860 m 0.6 mm total 0.5 mm snow 0.1 mm uncertain 0 mm rain
JMA GSM · Mid · 1860 m 0.6 mm total 0.5 mm snow 0.1 mm uncertain 0 mm rain
Models · toggle
Estimated snow level by model in metres above sea level, with selectable model precipitation beneath on the same time axis Wet-bulb-derived snow level from ECMWF IFS, ECMWF AIFS, GFS, ICON, plotted against the resort's elevation range. UKMO Global and JMA GSM are also plotted but hidden until switched on with the model legend above. Estimate mode continues sub-zero surface hours below model terrain using a lapse-rate estimate. Terrain upper bound mode stops those hours at the model terrain and leaves phase beneath unresolved. Precipitation colours and totals are evaluated at Mid · 1860 m. The selected precipitation model receives the strongest line emphasis; other models receive medium emphasis where their own precipitation is falling. The histogram beneath follows the page's selected precipitation model. Estimated snow level · metres AMSL Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 500 1000 1500 2000 base 1755 m top 1964 m Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1400 1600 1800 2000 2200 base 1755 m top 1964 m 0 1.1 2.2 mm/h ECMWF IFS precipitation · phase at Mid · 1860 m 25.4 mm total 0 0.3 0.7 mm/h ECMWF AIFS precipitation · phase at Mid · 1860 m 13.1 mm total 0 0.9 1.8 mm/h GFS precipitation · phase at Mid · 1860 m 15.3 mm total 0 0.8 1.7 mm/h ICON precipitation · phase at Mid · 1860 m 13 mm total 0 0.6 1.2 mm/h UKMO Global precipitation · phase at Mid · 1860 m 17.6 mm total 0 0.3 0.5 mm/h JMA GSM precipitation · phase at Mid · 1860 m 0.6 mm total
ECMWF IFS 25.4 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 2.2 0 ECMWF AIFS 13.1 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.7 0 GFS 15.3 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.8 0 ICON 13 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.7 0 UKMO Global 17.6 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.2 0 JMA GSM 0.6 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.5 0 IFS 9 km surface; sampled -36.380, 148.318; model terrain 1613 m; Sun 2 1600hrs AEST · 0600Z IFS 9 km surface · unphased local reference 37.6 mm precip 28.3 mm native SWE Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 2.2 0
snow uncertain rain 9 km reference · unphased
Snow-level method · experimental
ECMWF IFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1466 m; lapse-estimated 40 m below the model surface; 98 h estimated below model terrain at 6.5 °C/km
ECMWF AIFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1466 m; resolved between surface and 700 hPa, 1484 m apart; 39 h estimated below model terrain at 6.5 °C/km
GFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1466 m; lapse-estimated 209 m below the model surface; 121 h estimated below model terrain at 6.5 °C/km
ICON
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1466 m; lapse-estimated 2 m below the model surface; 114 h estimated below model terrain at 6.5 °C/km
UKMO Global
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1466 m; resolved between 850 hPa and 800 hPa, 487 m apart; 90 h estimated below model terrain at 6.5 °C/km
JMA GSM
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1466 m; resolved between surface and 850 hPa, 34 m apart; 41 h estimated below model terrain at 6.5 °C/km
ECMWF IFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ECMWF AIFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
GFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ICON
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
UKMO Global
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
JMA GSM
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound

Where the wet-bulb is already below zero at a model’s grid terrain, the continuous line extends downward using a 6.5 °C/km environmental lapse-rate estimate, with the uncertainty band widened across a 4.5–8.5 °C/km range. It is useful below-terrain guidance, not a model level directly resolved there.

Dashed sections stop at the model’s grid terrain. They are upper bounds: the wet-bulb zero is somewhere at or below that height, but this view does not estimate how far below. Phase below the bound remains uncertain.

The shaded band is a heuristic uncertainty around ECMWF IFS’s snow level. Each coloured snow-level line is emphasised where that model forecasts precipitation. The selected precipitation model receives the strongest emphasis because it also supplies the primary histogram and headline; other wet model lines remain medium-weight. Phase colours and totals here are judged at Mid · 1860 m.

Model-grid SWE is ECMWF IFS’s native sf field (parameter 144), expressed as liquid water equivalent at the model grid cell and its terrain. It is shown as an independent comparison: it does not alter the resort-elevation wet-bulb phase analysis and is not a settled-snow depth.

IFS 9 km surface is a separate native-resolution deterministic IFS surface sample. Its precipitation bars are intentionally unphased: this feed does not supply the pressure-level temperature/humidity profile used by the snow-level method. Native SWE is shown independently and does not alter the 25 km profile or ensemble products. Sampled cell -36.380, 148.318 · model terrain 1613 m · Sun 2 1600hrs AEST · 0600Z.

Model run Sun 2 1000hrs AEST · 0000Z · 13 h ago · fetched 1 min ago

Calculation method

Snow level is the lowest height at which the model’s own WET-BULB temperature crosses 0 °C — the operational definition NOAA’s National Blend of Models uses. Above that height precipitation reaches the ground as snow; below it, it melts on the way down. The wet-bulb matters rather than the ordinary (dry-bulb) temperature because falling snow is cooled by its own evaporating meltwater: in dry air snow reaches the ground at air temperatures well above freezing, and a dry-bulb rule would call that rain. Wet-bulb is solved from the psychrometric equation at each level’s own pressure — evaporative cooling is stronger in thinner air, so a sea-level formula applied at 700 hPa reads too warm and pushes the snow level too high. The profile uses each model’s pressure-level temperature and humidity (ECMWF publishes 1000/925/850/700/600/500 hPa; GFS and ICON add 950/900/800) and only levels above the model’s own terrain, since lower ones lie inside the mountain. Where the wet-bulb is already below zero at that terrain there is no crossing to locate: the line continues below terrain using a 6.5 °C/km environmental lapse-rate estimate. These sections are lighter than crossings directly resolved between model levels, and their uncertainty spans 4.5–8.5 °C/km. The shaded band is a HEURISTIC uncertainty: assumed temperature errors propagated through the measured lapse rate. Its constants are our estimate, not a published figure, which is why each model’s disclosure also states the actual pressure levels its crossing was resolved between. Precipitation totals are millimetres of LIQUID EQUIVALENT, which is what the models publish — not a settled snow depth. We deliberately do not convert 1000–500 hPa thickness into metres: the textbook 5400 m rule is calibrated for the Northern Hemisphere and was out by more than a kilometre when checked against a real Australian snow event. Background

Weather data by Open-Meteo.com · ECMWF IFS — © ECMWF, licensed CC BY 4.0

Model comparison, run times and meteograms for Charlotte Pass → · ACCESS-G currently unavailable

Selwyn NSW · 1492–1614 m

Snow level and precipitation

ECMWF IFS · Mid · 1553 m 10.6 mm total 4.5 mm snow 6.1 mm uncertain 0 mm rain 0.6 mm model-grid SWE
ECMWF IFS · Mid · 1553 m 10.6 mm total 4.5 mm snow 6.1 mm uncertain 0 mm rain 0.6 mm model-grid SWE
ECMWF AIFS · Mid · 1553 m 10.6 mm total 3 mm snow 3.8 mm uncertain 3.8 mm rain
ECMWF AIFS · Mid · 1553 m 10.6 mm total 3 mm snow 3.8 mm uncertain 3.8 mm rain
GFS · Mid · 1553 m 10.7 mm total 9.6 mm snow 0.9 mm uncertain 0.2 mm rain
GFS · Mid · 1553 m 10.7 mm total 9.6 mm snow 0.9 mm uncertain 0.2 mm rain
ICON · Mid · 1553 m 10.3 mm total 2.9 mm snow 7.4 mm uncertain 0 mm rain
ICON · Mid · 1553 m 10.3 mm total 2.9 mm snow 7.4 mm uncertain 0 mm rain
UKMO Global · Mid · 1553 m 17.1 mm total 6.2 mm snow 3.2 mm uncertain 7.7 mm rain
UKMO Global · Mid · 1553 m 17.1 mm total 6.2 mm snow 3.2 mm uncertain 7.7 mm rain
JMA GSM · Mid · 1553 m 9.3 mm total 5.6 mm snow 2 mm uncertain 1.7 mm rain
JMA GSM · Mid · 1553 m 9.3 mm total 5.6 mm snow 2 mm uncertain 1.7 mm rain
Models · toggle
Estimated snow level by model in metres above sea level, with selectable model precipitation beneath on the same time axis Wet-bulb-derived snow level from ECMWF IFS, ECMWF AIFS, GFS, ICON, plotted against the resort's elevation range. UKMO Global and JMA GSM are also plotted but hidden until switched on with the model legend above. Estimate mode continues sub-zero surface hours below model terrain using a lapse-rate estimate. Terrain upper bound mode stops those hours at the model terrain and leaves phase beneath unresolved. Precipitation colours and totals are evaluated at Mid · 1553 m. The selected precipitation model receives the strongest line emphasis; other models receive medium emphasis where their own precipitation is falling. The histogram beneath follows the page's selected precipitation model. Estimated snow level · metres AMSL Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0 500 1000 1500 2000 base 1492 m top 1614 m Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1500 2000 base 1492 m top 1614 m 0 0.4 0.8 mm/h ECMWF IFS precipitation · phase at Mid · 1553 m 10.6 mm total 0 0.4 0.8 mm/h ECMWF AIFS precipitation · phase at Mid · 1553 m 10.6 mm total 0 0.5 1.0 mm/h GFS precipitation · phase at Mid · 1553 m 10.7 mm total 0 0.9 1.9 mm/h ICON precipitation · phase at Mid · 1553 m 10.3 mm total 0 0.5 1.0 mm/h UKMO Global precipitation · phase at Mid · 1553 m 17.1 mm total 0 0.3 0.5 mm/h JMA GSM precipitation · phase at Mid · 1553 m 9.3 mm total
ECMWF IFS 10.6 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.8 0 ECMWF AIFS 10.6 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.8 0 GFS 10.7 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.0 0 ICON 10.3 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.9 0 UKMO Global 17.1 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.0 0 JMA GSM 9.3 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.5 0 IFS 9 km surface; sampled -35.888, 148.488; model terrain 1400 m; Sun 2 1600hrs AEST · 0600Z IFS 9 km surface · unphased local reference 16.4 mm precip 9.6 mm native SWE Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.4 0
snow uncertain rain 9 km reference · unphased
Snow-level method · experimental
ECMWF IFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1238 m; resolved between 850 hPa and 700 hPa, 1545 m apart; 34 h estimated below model terrain at 6.5 °C/km
ECMWF AIFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1238 m; resolved between 850 hPa and 700 hPa, 1547 m apart; 31 h estimated below model terrain at 6.5 °C/km
GFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1238 m; lapse-estimated 126 m below the model surface; 89 h estimated below model terrain at 6.5 °C/km
ICON
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1238 m; resolved between 850 hPa and 800 hPa, 485 m apart; 33 h estimated below model terrain at 6.5 °C/km
UKMO Global
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1238 m; resolved between 850 hPa and 800 hPa, 487 m apart; 61 h estimated below model terrain at 6.5 °C/km
JMA GSM
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1238 m; resolved between surface and 850 hPa, 292 m apart; 78 h estimated below model terrain at 6.5 °C/km
ECMWF IFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ECMWF AIFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
GFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ICON
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
UKMO Global
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
JMA GSM
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound

Where the wet-bulb is already below zero at a model’s grid terrain, the continuous line extends downward using a 6.5 °C/km environmental lapse-rate estimate, with the uncertainty band widened across a 4.5–8.5 °C/km range. It is useful below-terrain guidance, not a model level directly resolved there.

Dashed sections stop at the model’s grid terrain. They are upper bounds: the wet-bulb zero is somewhere at or below that height, but this view does not estimate how far below. Phase below the bound remains uncertain.

The shaded band is a heuristic uncertainty around ECMWF IFS’s snow level. Each coloured snow-level line is emphasised where that model forecasts precipitation. The selected precipitation model receives the strongest emphasis because it also supplies the primary histogram and headline; other wet model lines remain medium-weight. Phase colours and totals here are judged at Mid · 1553 m.

Model-grid SWE is ECMWF IFS’s native sf field (parameter 144), expressed as liquid water equivalent at the model grid cell and its terrain. It is shown as an independent comparison: it does not alter the resort-elevation wet-bulb phase analysis and is not a settled-snow depth.

IFS 9 km surface is a separate native-resolution deterministic IFS surface sample. Its precipitation bars are intentionally unphased: this feed does not supply the pressure-level temperature/humidity profile used by the snow-level method. Native SWE is shown independently and does not alter the 25 km profile or ensemble products. Sampled cell -35.888, 148.488 · model terrain 1400 m · Sun 2 1600hrs AEST · 0600Z.

Model run Sun 2 1000hrs AEST · 0000Z · 13 h ago · fetched 1 min ago

Calculation method

Snow level is the lowest height at which the model’s own WET-BULB temperature crosses 0 °C — the operational definition NOAA’s National Blend of Models uses. Above that height precipitation reaches the ground as snow; below it, it melts on the way down. The wet-bulb matters rather than the ordinary (dry-bulb) temperature because falling snow is cooled by its own evaporating meltwater: in dry air snow reaches the ground at air temperatures well above freezing, and a dry-bulb rule would call that rain. Wet-bulb is solved from the psychrometric equation at each level’s own pressure — evaporative cooling is stronger in thinner air, so a sea-level formula applied at 700 hPa reads too warm and pushes the snow level too high. The profile uses each model’s pressure-level temperature and humidity (ECMWF publishes 1000/925/850/700/600/500 hPa; GFS and ICON add 950/900/800) and only levels above the model’s own terrain, since lower ones lie inside the mountain. Where the wet-bulb is already below zero at that terrain there is no crossing to locate: the line continues below terrain using a 6.5 °C/km environmental lapse-rate estimate. These sections are lighter than crossings directly resolved between model levels, and their uncertainty spans 4.5–8.5 °C/km. The shaded band is a HEURISTIC uncertainty: assumed temperature errors propagated through the measured lapse rate. Its constants are our estimate, not a published figure, which is why each model’s disclosure also states the actual pressure levels its crossing was resolved between. Precipitation totals are millimetres of LIQUID EQUIVALENT, which is what the models publish — not a settled snow depth. We deliberately do not convert 1000–500 hPa thickness into metres: the textbook 5400 m rule is calibrated for the Northern Hemisphere and was out by more than a kilometre when checked against a real Australian snow event. Background

Weather data by Open-Meteo.com · ECMWF IFS — © ECMWF, licensed CC BY 4.0

Model comparison, run times and meteograms for Selwyn → · ACCESS-G currently unavailable

Mt Hotham VIC · 1450–1845 m

Snow level and precipitation

ECMWF IFS · Mid · 1648 m 17.6 mm total 7.6 mm snow 10 mm uncertain 0 mm rain 15.1 mm model-grid SWE
ECMWF IFS · Mid · 1648 m 17.6 mm total 7.6 mm snow 10 mm uncertain 0 mm rain 15.1 mm model-grid SWE
ECMWF AIFS · Mid · 1648 m 13.2 mm total 5.3 mm snow 6.3 mm uncertain 1.6 mm rain
ECMWF AIFS · Mid · 1648 m 13.2 mm total 5.3 mm snow 6.3 mm uncertain 1.6 mm rain
GFS · Mid · 1648 m 25.4 mm total 23.8 mm snow 0.9 mm uncertain 0.7 mm rain
GFS · Mid · 1648 m 25.4 mm total 23.8 mm snow 0.9 mm uncertain 0.7 mm rain
ICON · Mid · 1648 m 13 mm total 1.2 mm snow 11.5 mm uncertain 0.3 mm rain
ICON · Mid · 1648 m 13 mm total 1.2 mm snow 11.5 mm uncertain 0.3 mm rain
UKMO Global · Mid · 1648 m 55.1 mm total 20.3 mm snow 13.2 mm uncertain 21.6 mm rain
UKMO Global · Mid · 1648 m 55.1 mm total 20.3 mm snow 13.2 mm uncertain 21.6 mm rain
JMA GSM · Mid · 1648 m 19.6 mm total 13 mm snow 1.4 mm uncertain 5.2 mm rain
JMA GSM · Mid · 1648 m 19.6 mm total 13 mm snow 1.4 mm uncertain 5.2 mm rain
Models · toggle
Estimated snow level by model in metres above sea level, with selectable model precipitation beneath on the same time axis Wet-bulb-derived snow level from ECMWF IFS, ECMWF AIFS, GFS, ICON, plotted against the resort's elevation range. UKMO Global and JMA GSM are also plotted but hidden until switched on with the model legend above. Estimate mode continues sub-zero surface hours below model terrain using a lapse-rate estimate. Terrain upper bound mode stops those hours at the model terrain and leaves phase beneath unresolved. Precipitation colours and totals are evaluated at Mid · 1648 m. The selected precipitation model receives the strongest line emphasis; other models receive medium emphasis where their own precipitation is falling. The histogram beneath follows the page's selected precipitation model. Estimated snow level · metres AMSL Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 500 1000 1500 2000 base 1450 m village 1765 m top 1845 m Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1400 1600 1800 2000 base 1450 m village 1765 m top 1845 m 0 0.9 1.9 mm/h ECMWF IFS precipitation · phase at Mid · 1648 m 17.6 mm total 0 0.3 0.6 mm/h ECMWF AIFS precipitation · phase at Mid · 1648 m 13.2 mm total 0 1.1 2.1 mm/h GFS precipitation · phase at Mid · 1648 m 25.4 mm total 0 0.9 1.8 mm/h ICON precipitation · phase at Mid · 1648 m 13 mm total 0 1.3 2.6 mm/h UKMO Global precipitation · phase at Mid · 1648 m 55.1 mm total 0 0.5 1.0 mm/h JMA GSM precipitation · phase at Mid · 1648 m 19 mm total
ECMWF IFS 17.6 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.9 0 ECMWF AIFS 13.2 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.6 0 GFS 25.4 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 2.1 0 ICON 13 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.8 0 UKMO Global 55.1 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 2.6 0 JMA GSM 19 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.0 0 IFS 9 km surface; sampled -36.942, 147.154; model terrain 1388 m; Sun 2 1600hrs AEST · 0600Z IFS 9 km surface · unphased local reference 33.6 mm precip 23.5 mm native SWE Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 2.5 0
snow uncertain rain 9 km reference · unphased
Snow-level method · experimental
ECMWF IFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1444 m; resolved between surface and 700 hPa, 1498 m apart; 91 h estimated below model terrain at 6.5 °C/km
ECMWF AIFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1444 m; resolved between surface and 700 hPa, 1496 m apart; 28 h estimated below model terrain at 6.5 °C/km
GFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1444 m; resolved between surface and 800 hPa, 458 m apart; 85 h estimated below model terrain at 6.5 °C/km
ICON
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1444 m; resolved between surface and 800 hPa, 425 m apart; 42 h estimated below model terrain at 6.5 °C/km
UKMO Global
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1444 m; resolved between 850 hPa and 800 hPa, 486 m apart; 46 h estimated below model terrain at 6.5 °C/km
JMA GSM
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1444 m; resolved between surface and 850 hPa, 76 m apart; 14 h estimated below model terrain at 6.5 °C/km
ECMWF IFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ECMWF AIFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
GFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ICON
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
UKMO Global
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
JMA GSM
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound

Where the wet-bulb is already below zero at a model’s grid terrain, the continuous line extends downward using a 6.5 °C/km environmental lapse-rate estimate, with the uncertainty band widened across a 4.5–8.5 °C/km range. It is useful below-terrain guidance, not a model level directly resolved there.

Dashed sections stop at the model’s grid terrain. They are upper bounds: the wet-bulb zero is somewhere at or below that height, but this view does not estimate how far below. Phase below the bound remains uncertain.

The shaded band is a heuristic uncertainty around ECMWF IFS’s snow level. Each coloured snow-level line is emphasised where that model forecasts precipitation. The selected precipitation model receives the strongest emphasis because it also supplies the primary histogram and headline; other wet model lines remain medium-weight. Phase colours and totals here are judged at Mid · 1648 m.

Model-grid SWE is ECMWF IFS’s native sf field (parameter 144), expressed as liquid water equivalent at the model grid cell and its terrain. It is shown as an independent comparison: it does not alter the resort-elevation wet-bulb phase analysis and is not a settled-snow depth.

IFS 9 km surface is a separate native-resolution deterministic IFS surface sample. Its precipitation bars are intentionally unphased: this feed does not supply the pressure-level temperature/humidity profile used by the snow-level method. Native SWE is shown independently and does not alter the 25 km profile or ensemble products. Sampled cell -36.942, 147.154 · model terrain 1388 m · Sun 2 1600hrs AEST · 0600Z.

Model run Sun 2 1000hrs AEST · 0000Z · 13 h ago · fetched 1 min ago

Calculation method

Snow level is the lowest height at which the model’s own WET-BULB temperature crosses 0 °C — the operational definition NOAA’s National Blend of Models uses. Above that height precipitation reaches the ground as snow; below it, it melts on the way down. The wet-bulb matters rather than the ordinary (dry-bulb) temperature because falling snow is cooled by its own evaporating meltwater: in dry air snow reaches the ground at air temperatures well above freezing, and a dry-bulb rule would call that rain. Wet-bulb is solved from the psychrometric equation at each level’s own pressure — evaporative cooling is stronger in thinner air, so a sea-level formula applied at 700 hPa reads too warm and pushes the snow level too high. The profile uses each model’s pressure-level temperature and humidity (ECMWF publishes 1000/925/850/700/600/500 hPa; GFS and ICON add 950/900/800) and only levels above the model’s own terrain, since lower ones lie inside the mountain. Where the wet-bulb is already below zero at that terrain there is no crossing to locate: the line continues below terrain using a 6.5 °C/km environmental lapse-rate estimate. These sections are lighter than crossings directly resolved between model levels, and their uncertainty spans 4.5–8.5 °C/km. The shaded band is a HEURISTIC uncertainty: assumed temperature errors propagated through the measured lapse rate. Its constants are our estimate, not a published figure, which is why each model’s disclosure also states the actual pressure levels its crossing was resolved between. Precipitation totals are millimetres of LIQUID EQUIVALENT, which is what the models publish — not a settled snow depth. We deliberately do not convert 1000–500 hPa thickness into metres: the textbook 5400 m rule is calibrated for the Northern Hemisphere and was out by more than a kilometre when checked against a real Australian snow event. Background

Weather data by Open-Meteo.com · ECMWF IFS — © ECMWF, licensed CC BY 4.0

Model comparison, run times and meteograms for Mt Hotham → · ACCESS-G currently unavailable

Falls Creek VIC · 1500–1780 m

Snow level and precipitation

ECMWF IFS · Mid · 1640 m 30.3 mm total 13.9 mm snow 16 mm uncertain 0.4 mm rain 10 mm model-grid SWE
ECMWF IFS · Mid · 1640 m 30.3 mm total 13.9 mm snow 16 mm uncertain 0.4 mm rain 10 mm model-grid SWE
ECMWF AIFS · Mid · 1640 m 20.5 mm total 7.5 mm snow 12.6 mm uncertain 0.4 mm rain
ECMWF AIFS · Mid · 1640 m 20.5 mm total 7.5 mm snow 12.6 mm uncertain 0.4 mm rain
GFS · Mid · 1640 m 25 mm total 23.3 mm snow 0.9 mm uncertain 0.8 mm rain
GFS · Mid · 1640 m 25 mm total 23.3 mm snow 0.9 mm uncertain 0.8 mm rain
ICON · Mid · 1640 m 20.7 mm total 4.5 mm snow 16.2 mm uncertain 0 mm rain
ICON · Mid · 1640 m 20.7 mm total 4.5 mm snow 16.2 mm uncertain 0 mm rain
UKMO Global · Mid · 1640 m 45.9 mm total 13.6 mm snow 9.7 mm uncertain 22.6 mm rain
UKMO Global · Mid · 1640 m 45.9 mm total 13.6 mm snow 9.7 mm uncertain 22.6 mm rain
JMA GSM · Mid · 1640 m 2.8 mm total 1.2 mm snow 1.6 mm uncertain 0 mm rain
JMA GSM · Mid · 1640 m 2.8 mm total 1.2 mm snow 1.6 mm uncertain 0 mm rain
Models · toggle
Estimated snow level by model in metres above sea level, with selectable model precipitation beneath on the same time axis Wet-bulb-derived snow level from ECMWF IFS, ECMWF AIFS, GFS, ICON, plotted against the resort's elevation range. UKMO Global and JMA GSM are also plotted but hidden until switched on with the model legend above. Estimate mode continues sub-zero surface hours below model terrain using a lapse-rate estimate. Terrain upper bound mode stops those hours at the model terrain and leaves phase beneath unresolved. Precipitation colours and totals are evaluated at Mid · 1640 m. The selected precipitation model receives the strongest line emphasis; other models receive medium emphasis where their own precipitation is falling. The histogram beneath follows the page's selected precipitation model. Estimated snow level · metres AMSL Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 500 1000 1500 2000 base 1500 m top 1780 m Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1000 1500 2000 base 1500 m top 1780 m 0 0.9 1.8 mm/h ECMWF IFS precipitation · phase at Mid · 1640 m 30.3 mm total 0 0.6 1.1 mm/h ECMWF AIFS precipitation · phase at Mid · 1640 m 20.5 mm total 0 1.3 2.5 mm/h GFS precipitation · phase at Mid · 1640 m 25 mm total 0 1.4 2.8 mm/h ICON precipitation · phase at Mid · 1640 m 20.7 mm total 0 1.3 2.6 mm/h UKMO Global precipitation · phase at Mid · 1640 m 45.9 mm total 0 0.3 0.5 mm/h JMA GSM precipitation · phase at Mid · 1640 m 2.2 mm total
ECMWF IFS 30.3 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.8 0 ECMWF AIFS 20.5 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.1 0 GFS 25 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 2.5 0 ICON 20.7 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 2.8 0 UKMO Global 45.9 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 2.6 0 JMA GSM 2.2 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.5 0 IFS 9 km surface; sampled -36.872, 147.316; model terrain 1523 m; Sun 2 1600hrs AEST · 0600Z IFS 9 km surface · unphased local reference 25.7 mm precip 22.7 mm native SWE Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 2.1 0
snow uncertain rain 9 km reference · unphased
Snow-level method · experimental
ECMWF IFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1129 m; resolved between 850 hPa and 700 hPa, 1544 m apart; 24 h estimated below model terrain at 6.5 °C/km
ECMWF AIFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1129 m; resolved between 850 hPa and 700 hPa, 1546 m apart; 15 h estimated below model terrain at 6.5 °C/km
GFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1129 m; resolved between surface and 850 hPa, 307 m apart; 89 h estimated below model terrain at 6.5 °C/km
ICON
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1129 m; resolved between 850 hPa and 800 hPa, 485 m apart; 60 h estimated below model terrain at 6.5 °C/km
UKMO Global
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1129 m; resolved between 850 hPa and 800 hPa, 486 m apart; 45 h estimated below model terrain at 6.5 °C/km
JMA GSM
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1129 m; resolved between surface and 850 hPa, 391 m apart; 12 h estimated below model terrain at 6.5 °C/km
ECMWF IFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ECMWF AIFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
GFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ICON
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
UKMO Global
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
JMA GSM
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound

Where the wet-bulb is already below zero at a model’s grid terrain, the continuous line extends downward using a 6.5 °C/km environmental lapse-rate estimate, with the uncertainty band widened across a 4.5–8.5 °C/km range. It is useful below-terrain guidance, not a model level directly resolved there.

Dashed sections stop at the model’s grid terrain. They are upper bounds: the wet-bulb zero is somewhere at or below that height, but this view does not estimate how far below. Phase below the bound remains uncertain.

The shaded band is a heuristic uncertainty around ECMWF IFS’s snow level. Each coloured snow-level line is emphasised where that model forecasts precipitation. The selected precipitation model receives the strongest emphasis because it also supplies the primary histogram and headline; other wet model lines remain medium-weight. Phase colours and totals here are judged at Mid · 1640 m.

Model-grid SWE is ECMWF IFS’s native sf field (parameter 144), expressed as liquid water equivalent at the model grid cell and its terrain. It is shown as an independent comparison: it does not alter the resort-elevation wet-bulb phase analysis and is not a settled-snow depth.

IFS 9 km surface is a separate native-resolution deterministic IFS surface sample. Its precipitation bars are intentionally unphased: this feed does not supply the pressure-level temperature/humidity profile used by the snow-level method. Native SWE is shown independently and does not alter the 25 km profile or ensemble products. Sampled cell -36.872, 147.316 · model terrain 1523 m · Sun 2 1600hrs AEST · 0600Z.

Model run Sun 2 1000hrs AEST · 0000Z · 13 h ago · fetched 1 min ago

Calculation method

Snow level is the lowest height at which the model’s own WET-BULB temperature crosses 0 °C — the operational definition NOAA’s National Blend of Models uses. Above that height precipitation reaches the ground as snow; below it, it melts on the way down. The wet-bulb matters rather than the ordinary (dry-bulb) temperature because falling snow is cooled by its own evaporating meltwater: in dry air snow reaches the ground at air temperatures well above freezing, and a dry-bulb rule would call that rain. Wet-bulb is solved from the psychrometric equation at each level’s own pressure — evaporative cooling is stronger in thinner air, so a sea-level formula applied at 700 hPa reads too warm and pushes the snow level too high. The profile uses each model’s pressure-level temperature and humidity (ECMWF publishes 1000/925/850/700/600/500 hPa; GFS and ICON add 950/900/800) and only levels above the model’s own terrain, since lower ones lie inside the mountain. Where the wet-bulb is already below zero at that terrain there is no crossing to locate: the line continues below terrain using a 6.5 °C/km environmental lapse-rate estimate. These sections are lighter than crossings directly resolved between model levels, and their uncertainty spans 4.5–8.5 °C/km. The shaded band is a HEURISTIC uncertainty: assumed temperature errors propagated through the measured lapse rate. Its constants are our estimate, not a published figure, which is why each model’s disclosure also states the actual pressure levels its crossing was resolved between. Precipitation totals are millimetres of LIQUID EQUIVALENT, which is what the models publish — not a settled snow depth. We deliberately do not convert 1000–500 hPa thickness into metres: the textbook 5400 m rule is calibrated for the Northern Hemisphere and was out by more than a kilometre when checked against a real Australian snow event. Background

Weather data by Open-Meteo.com · ECMWF IFS — © ECMWF, licensed CC BY 4.0

Model comparison, run times and meteograms for Falls Creek → · ACCESS-G currently unavailable

Mt Buller VIC · 1375–1780 m

Snow level and precipitation

ECMWF IFS · Mid · 1578 m 25.9 mm total 12.9 mm snow 12.7 mm uncertain 0.3 mm rain 7.5 mm model-grid SWE
ECMWF IFS · Mid · 1578 m 25.9 mm total 12.9 mm snow 12.7 mm uncertain 0.3 mm rain 7.5 mm model-grid SWE
ECMWF AIFS · Mid · 1578 m 18.3 mm total 6.9 mm snow 11.3 mm uncertain 0.1 mm rain
ECMWF AIFS · Mid · 1578 m 18.3 mm total 6.9 mm snow 11.3 mm uncertain 0.1 mm rain
GFS · Mid · 1578 m 29.5 mm total 27.1 mm snow 2.3 mm uncertain 0.1 mm rain
GFS · Mid · 1578 m 29.5 mm total 27.1 mm snow 2.3 mm uncertain 0.1 mm rain
ICON · Mid · 1578 m 28.4 mm total 6.7 mm snow 18.3 mm uncertain 3.4 mm rain
ICON · Mid · 1578 m 28.4 mm total 6.7 mm snow 18.3 mm uncertain 3.4 mm rain
UKMO Global · Mid · 1578 m 50.2 mm total 13.6 mm snow 18.5 mm uncertain 18.1 mm rain
UKMO Global · Mid · 1578 m 50.2 mm total 13.6 mm snow 18.5 mm uncertain 18.1 mm rain
JMA GSM · Mid · 1578 m 22.9 mm total 9.6 mm snow 6.2 mm uncertain 7.1 mm rain
JMA GSM · Mid · 1578 m 22.9 mm total 9.6 mm snow 6.2 mm uncertain 7.1 mm rain
Models · toggle
Estimated snow level by model in metres above sea level, with selectable model precipitation beneath on the same time axis Wet-bulb-derived snow level from ECMWF IFS, ECMWF AIFS, GFS, ICON, plotted against the resort's elevation range. UKMO Global and JMA GSM are also plotted but hidden until switched on with the model legend above. Estimate mode continues sub-zero surface hours below model terrain using a lapse-rate estimate. Terrain upper bound mode stops those hours at the model terrain and leaves phase beneath unresolved. Precipitation colours and totals are evaluated at Mid · 1578 m. The selected precipitation model receives the strongest line emphasis; other models receive medium emphasis where their own precipitation is falling. The histogram beneath follows the page's selected precipitation model. Estimated snow level · metres AMSL Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 500 1000 1500 2000 base 1375 m top 1780 m Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1000 1500 2000 base 1375 m top 1780 m 0 0.8 1.7 mm/h ECMWF IFS precipitation · phase at Mid · 1578 m 25.9 mm total 0 0.5 0.9 mm/h ECMWF AIFS precipitation · phase at Mid · 1578 m 18.3 mm total 0 1.9 3.7 mm/h GFS precipitation · phase at Mid · 1578 m 29.5 mm total 0 1.1 2.3 mm/h ICON precipitation · phase at Mid · 1578 m 28.4 mm total 0 0.8 1.6 mm/h UKMO Global precipitation · phase at Mid · 1578 m 50.2 mm total 0 0.6 1.1 mm/h JMA GSM precipitation · phase at Mid · 1578 m 22.9 mm total
ECMWF IFS 25.9 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.7 0 ECMWF AIFS 18.3 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.9 0 GFS 29.5 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 3.7 0 ICON 28.4 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 2.3 0 UKMO Global 50.2 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.6 0 JMA GSM 22.9 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.1 0 IFS 9 km surface; sampled -37.153, 146.429; model terrain 1055 m; Sun 2 1600hrs AEST · 0600Z IFS 9 km surface · unphased local reference 34.9 mm precip 5.2 mm native SWE Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.8 0
snow uncertain rain 9 km reference · unphased
Snow-level method · experimental
ECMWF IFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1137 m; resolved between 850 hPa and 700 hPa, 1543 m apart; 36 h estimated below model terrain at 6.5 °C/km
ECMWF AIFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1137 m; resolved between 850 hPa and 700 hPa, 1548 m apart; 10 h estimated below model terrain at 6.5 °C/km
GFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1137 m; resolved between surface and 850 hPa, 358 m apart; 32 h estimated below model terrain at 6.5 °C/km
ICON
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1137 m; resolved between 850 hPa and 800 hPa, 486 m apart
UKMO Global
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1137 m; resolved between surface and 850 hPa, 365 m apart; 21 h estimated below model terrain at 6.5 °C/km
JMA GSM
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1137 m; resolved between 850 hPa and 700 hPa, 1549 m apart; 13 h estimated below model terrain at 6.5 °C/km
ECMWF IFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ECMWF AIFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
GFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ICON
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
UKMO Global
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
JMA GSM
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound

Where the wet-bulb is already below zero at a model’s grid terrain, the continuous line extends downward using a 6.5 °C/km environmental lapse-rate estimate, with the uncertainty band widened across a 4.5–8.5 °C/km range. It is useful below-terrain guidance, not a model level directly resolved there.

Dashed sections stop at the model’s grid terrain. They are upper bounds: the wet-bulb zero is somewhere at or below that height, but this view does not estimate how far below. Phase below the bound remains uncertain.

The shaded band is a heuristic uncertainty around ECMWF IFS’s snow level. Each coloured snow-level line is emphasised where that model forecasts precipitation. The selected precipitation model receives the strongest emphasis because it also supplies the primary histogram and headline; other wet model lines remain medium-weight. Phase colours and totals here are judged at Mid · 1578 m.

Model-grid SWE is ECMWF IFS’s native sf field (parameter 144), expressed as liquid water equivalent at the model grid cell and its terrain. It is shown as an independent comparison: it does not alter the resort-elevation wet-bulb phase analysis and is not a settled-snow depth.

IFS 9 km surface is a separate native-resolution deterministic IFS surface sample. Its precipitation bars are intentionally unphased: this feed does not supply the pressure-level temperature/humidity profile used by the snow-level method. Native SWE is shown independently and does not alter the 25 km profile or ensemble products. Sampled cell -37.153, 146.429 · model terrain 1055 m · Sun 2 1600hrs AEST · 0600Z.

Model run Sun 2 1000hrs AEST · 0000Z · 13 h ago · fetched 1 min ago

Calculation method

Snow level is the lowest height at which the model’s own WET-BULB temperature crosses 0 °C — the operational definition NOAA’s National Blend of Models uses. Above that height precipitation reaches the ground as snow; below it, it melts on the way down. The wet-bulb matters rather than the ordinary (dry-bulb) temperature because falling snow is cooled by its own evaporating meltwater: in dry air snow reaches the ground at air temperatures well above freezing, and a dry-bulb rule would call that rain. Wet-bulb is solved from the psychrometric equation at each level’s own pressure — evaporative cooling is stronger in thinner air, so a sea-level formula applied at 700 hPa reads too warm and pushes the snow level too high. The profile uses each model’s pressure-level temperature and humidity (ECMWF publishes 1000/925/850/700/600/500 hPa; GFS and ICON add 950/900/800) and only levels above the model’s own terrain, since lower ones lie inside the mountain. Where the wet-bulb is already below zero at that terrain there is no crossing to locate: the line continues below terrain using a 6.5 °C/km environmental lapse-rate estimate. These sections are lighter than crossings directly resolved between model levels, and their uncertainty spans 4.5–8.5 °C/km. The shaded band is a HEURISTIC uncertainty: assumed temperature errors propagated through the measured lapse rate. Its constants are our estimate, not a published figure, which is why each model’s disclosure also states the actual pressure levels its crossing was resolved between. Precipitation totals are millimetres of LIQUID EQUIVALENT, which is what the models publish — not a settled snow depth. We deliberately do not convert 1000–500 hPa thickness into metres: the textbook 5400 m rule is calibrated for the Northern Hemisphere and was out by more than a kilometre when checked against a real Australian snow event. Background

Weather data by Open-Meteo.com · ECMWF IFS — © ECMWF, licensed CC BY 4.0

Model comparison, run times and meteograms for Mt Buller → · ACCESS-G currently unavailable

Mt Baw Baw VIC · 1450–1564 m

Snow level and precipitation

ECMWF IFS · Mid · 1507 m 30.1 mm total 6.3 mm snow 22.2 mm uncertain 1.6 mm rain 1 mm model-grid SWE
ECMWF IFS · Mid · 1507 m 30.1 mm total 6.3 mm snow 22.2 mm uncertain 1.6 mm rain 1 mm model-grid SWE
ECMWF AIFS · Mid · 1507 m 17.9 mm total 1.8 mm snow 14.5 mm uncertain 1.6 mm rain
ECMWF AIFS · Mid · 1507 m 17.9 mm total 1.8 mm snow 14.5 mm uncertain 1.6 mm rain
GFS · Mid · 1507 m 31.6 mm total 9 mm snow 22.5 mm uncertain 0.1 mm rain
GFS · Mid · 1507 m 31.6 mm total 9 mm snow 22.5 mm uncertain 0.1 mm rain
ICON · Mid · 1507 m 10.5 mm total 1.8 mm snow 4.9 mm uncertain 3.8 mm rain
ICON · Mid · 1507 m 10.5 mm total 1.8 mm snow 4.9 mm uncertain 3.8 mm rain
UKMO Global · Mid · 1507 m 47.3 mm total 3.1 mm snow 26.5 mm uncertain 17.7 mm rain
UKMO Global · Mid · 1507 m 47.3 mm total 3.1 mm snow 26.5 mm uncertain 17.7 mm rain
JMA GSM · Mid · 1507 m 11 mm total 3.1 mm snow 5.9 mm uncertain 2 mm rain
JMA GSM · Mid · 1507 m 11 mm total 3.1 mm snow 5.9 mm uncertain 2 mm rain
Models · toggle
Estimated snow level by model in metres above sea level, with selectable model precipitation beneath on the same time axis Wet-bulb-derived snow level from ECMWF IFS, ECMWF AIFS, GFS, ICON, plotted against the resort's elevation range. UKMO Global and JMA GSM are also plotted but hidden until switched on with the model legend above. Estimate mode continues sub-zero surface hours below model terrain using a lapse-rate estimate. Terrain upper bound mode stops those hours at the model terrain and leaves phase beneath unresolved. Precipitation colours and totals are evaluated at Mid · 1507 m. The selected precipitation model receives the strongest line emphasis; other models receive medium emphasis where their own precipitation is falling. The histogram beneath follows the page's selected precipitation model. Estimated snow level · metres AMSL Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 500 1000 1500 2000 base 1450 m top 1564 m Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1000 1500 2000 base 1450 m top 1564 m 0 0.6 1.1 mm/h ECMWF IFS precipitation · phase at Mid · 1507 m 30.1 mm total 0 0.3 0.7 mm/h ECMWF AIFS precipitation · phase at Mid · 1507 m 17.9 mm total 0 1.9 3.9 mm/h GFS precipitation · phase at Mid · 1507 m 31.6 mm total 0 0.4 0.8 mm/h ICON precipitation · phase at Mid · 1507 m 10.5 mm total 0 1.1 2.1 mm/h UKMO Global precipitation · phase at Mid · 1507 m 47.3 mm total 0 0.3 0.5 mm/h JMA GSM precipitation · phase at Mid · 1507 m 11 mm total
ECMWF IFS 30.1 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.1 0 ECMWF AIFS 17.9 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.7 0 GFS 31.6 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 3.9 0 ICON 10.5 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.8 0 UKMO Global 47.3 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 2.1 0 JMA GSM 11 mm total Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 0.5 0 IFS 9 km surface; sampled -37.786, 146.265; model terrain 936 m; Sun 2 1600hrs AEST · 0600Z IFS 9 km surface · unphased local reference 24.8 mm precip 1 mm native SWE Mon 3 Tue 4 Wed 5 Thu 6 Fri 7 Sat 8 Sun 9 1.5 0
snow uncertain rain 9 km reference · unphased
Snow-level method · experimental
ECMWF IFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 982 m; resolved between 850 hPa and 700 hPa, 1548 m apart; 28 h estimated below model terrain at 6.5 °C/km
ECMWF AIFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 982 m; resolved between 850 hPa and 700 hPa, 1552 m apart
GFS
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 900/850/800/700/600/500 hPa above 982 m; resolved between 900 hPa and 850 hPa, 459 m apart; 1 h estimated below model terrain at 6.5 °C/km
ICON
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 900/850/800/700/600/500 hPa above 982 m; resolved between 850 hPa and 800 hPa, 488 m apart
UKMO Global
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 900/850/800/700/600/500 hPa above 982 m; resolved between 850 hPa and 800 hPa, 485 m apart; 12 h estimated below model terrain at 6.5 °C/km
JMA GSM
Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 982 m; resolved between 850 hPa and 700 hPa, 1559 m apart
ECMWF IFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ECMWF AIFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
GFS
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
ICON
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
UKMO Global
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound
JMA GSM
Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound

Where the wet-bulb is already below zero at a model’s grid terrain, the continuous line extends downward using a 6.5 °C/km environmental lapse-rate estimate, with the uncertainty band widened across a 4.5–8.5 °C/km range. It is useful below-terrain guidance, not a model level directly resolved there.

Dashed sections stop at the model’s grid terrain. They are upper bounds: the wet-bulb zero is somewhere at or below that height, but this view does not estimate how far below. Phase below the bound remains uncertain.

The shaded band is a heuristic uncertainty around ECMWF IFS’s snow level. Each coloured snow-level line is emphasised where that model forecasts precipitation. The selected precipitation model receives the strongest emphasis because it also supplies the primary histogram and headline; other wet model lines remain medium-weight. Phase colours and totals here are judged at Mid · 1507 m.

Model-grid SWE is ECMWF IFS’s native sf field (parameter 144), expressed as liquid water equivalent at the model grid cell and its terrain. It is shown as an independent comparison: it does not alter the resort-elevation wet-bulb phase analysis and is not a settled-snow depth.

IFS 9 km surface is a separate native-resolution deterministic IFS surface sample. Its precipitation bars are intentionally unphased: this feed does not supply the pressure-level temperature/humidity profile used by the snow-level method. Native SWE is shown independently and does not alter the 25 km profile or ensemble products. Sampled cell -37.786, 146.265 · model terrain 936 m · Sun 2 1600hrs AEST · 0600Z.

Model run Sun 2 1000hrs AEST · 0000Z · 13 h ago · fetched 1 min ago

Calculation method

Snow level is the lowest height at which the model’s own WET-BULB temperature crosses 0 °C — the operational definition NOAA’s National Blend of Models uses. Above that height precipitation reaches the ground as snow; below it, it melts on the way down. The wet-bulb matters rather than the ordinary (dry-bulb) temperature because falling snow is cooled by its own evaporating meltwater: in dry air snow reaches the ground at air temperatures well above freezing, and a dry-bulb rule would call that rain. Wet-bulb is solved from the psychrometric equation at each level’s own pressure — evaporative cooling is stronger in thinner air, so a sea-level formula applied at 700 hPa reads too warm and pushes the snow level too high. The profile uses each model’s pressure-level temperature and humidity (ECMWF publishes 1000/925/850/700/600/500 hPa; GFS and ICON add 950/900/800) and only levels above the model’s own terrain, since lower ones lie inside the mountain. Where the wet-bulb is already below zero at that terrain there is no crossing to locate: the line continues below terrain using a 6.5 °C/km environmental lapse-rate estimate. These sections are lighter than crossings directly resolved between model levels, and their uncertainty spans 4.5–8.5 °C/km. The shaded band is a HEURISTIC uncertainty: assumed temperature errors propagated through the measured lapse rate. Its constants are our estimate, not a published figure, which is why each model’s disclosure also states the actual pressure levels its crossing was resolved between. Precipitation totals are millimetres of LIQUID EQUIVALENT, which is what the models publish — not a settled snow depth. We deliberately do not convert 1000–500 hPa thickness into metres: the textbook 5400 m rule is calibrated for the Northern Hemisphere and was out by more than a kilometre when checked against a real Australian snow event. Background

Weather data by Open-Meteo.com · ECMWF IFS — © ECMWF, licensed CC BY 4.0

Model comparison, run times and meteograms for Mt Baw Baw → · ACCESS-G currently unavailable