3–7 days — snow level and model spread

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, 1584 m apart; 9 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 700 hPa and 600 hPa, 1225 m apart

ECMWF IFS single cycle

Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700 hPa above 1353 m; resolved between 850 hPa and 700 hPa, 1581 m apart; 54% of hours; 3 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 1565 m; resolved between 800 hPa and 700 hPa, 1073 m apart; 3 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 1442 m; resolved between 700 hPa and 600 hPa, 1222 m apart; 10 h estimated below model terrain at 6.5 °C/km

UKMO Global

Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 800/700/600/500 hPa above 1613 m; resolved between 800 hPa and 700 hPa, 1084 m apart

JMA GSM

Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1284 m; resolved between 700 hPa and 600 hPa, 1226 m apart

ARPEGE World

Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1262 m; resolved between 800 hPa and 700 hPa, 1085 m apart

GDPS

Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/800/700/600/500 hPa above 1165 m; resolved between 700 hPa and 600 hPa, 1224 m apart; 5 h estimated below model terrain at 6.5 °C/km

NOAA AI-GFS

Estimated wet-bulb snow level — lowest wet-bulb zero (NBM definition), from 850/700/600/500 hPa above 1276 m; resolved between 850 hPa and 700 hPa, 1569 m apart; 63% of hours; 1 h clamped to the terrain — snow reaching the ground, so the line is an upper bound there

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

ECMWF IFS single cycle

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

ARPEGE World

Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound

GDPS

Profile wet-bulb zero; hours already sub-zero at grid terrain stop there as an upper bound

NOAA AI-GFS

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 a selected primary precipitation model’s snow level; switching that selection above switches the band with it. Each coloured snow-level line is emphasised where that model forecasts precipitation. A selected primary receives the strongest emphasis because it also supplies the main histogram and headline. With None selected, no band or headline is singled out, and every wet model line and phased precipitation track has equal weight. Phase colours and totals here are judged at Low · 1605 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.

ECMWF 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 · Wed 30 0400hrs AEST · 1800Z.

ECMWF IFS official 0.25° QPF is one exact ECMWF cycle read from that centre's own open-data service, not a provider's seamless blend of successive runs — the same cycle its own snow-level line above is derived from. Its bars are phased: the same producer that reads this run's tp/sf also reads its t/r/gh at 1000/925/850/700 hPa and surface 2t/2d (2 m relative humidity is derived from those two — this stream carries no 2 m RH field directly), so the wet-bulb method above has a genuine same-run profile to work from rather than a borrowed one. Because only four levels are fetched, the 1000–500 hPa thickness diagnostic is unavailable for this track specifically — the method never needs it, but it is worth naming as a gap other tracks on this page do not have. This stream carries no terrain-height field either, so the profile is anchored to this same 0.25° cell's terrain height as already resolved by the Open-Meteo ECMWF IFS model beside it, rather than a second, independently derived figure for the same cell. Bars are drawn across the 3 and 6 hour spans the accumulations actually cover, at each span's mm/h rate, at NATIVE cadence — plotted, not interpolated to hourly; the total is over this chart's hours only. This run's precipitation reaches +360 h, well past them, but its profile — and so its snow-level line and phased bars — only to +192 h; hours beyond that still carry precipitation but no phase, drawn unclassified (the official cycle is 00Z/12Z only, so it is always some hours older than the models' own cycle — see the run stamp above). Selected cell -36.500, 148.500 on a 0.25° grid · Tue 29 2200hrs AEST · 1200Z. Its native SWE is snowfall at that cell and the terrain the model gives it, which at 0.25° is a ~25 km average sitting well below this resort. A zero there means the model put none down at that height — it is not a statement about snow at the resort, and the snow-level plot above is what answers that question.

NOAA AI-GFS 0.25° is NOAA's experimental AI global model, one exact 0.25° cycle read straight from NOMADS as GRIB2 rather than through a provider. Two things about it differ from every other track here, and both are stated rather than smoothed over. It publishes no snowfall field at all — its surface stream carries 10 m winds, 2 m temperature, mean sea-level pressure and total precipitation, and nothing else. So there is no native SWE figure beside its total and there never will be; the snow shown in its bars is this page's own wet-bulb phase split of its precipitation, which is a different quantity from a model snowfall diagnostic. And it carries no 2 m humidity, so unlike the models beside it the surface cannot become a level of its profile — that profile starts at the lowest pressure level above the model's terrain instead. Its profile is TMP/SPFH/ HGT at 1000/925/850/700/600/500 hPa, the same six levels the ECMWF products on this page supply, with relative humidity derived from specific humidity at each level. Because 500 hPa is fetched, the 1000–500 hPa thickness diagnostic is available here — which the exact ECMWF run above cannot offer. Its terrain is not borrowed: it comes from the GFS 0.25° analysis this model is initialised on, so the elevation anchoring its profile is the model's own. Bars are drawn across the 6 hour spans the accumulations actually cover, at each span's mm/h rate, at NATIVE cadence; the total is over this chart's hours only. This run's precipitation reaches +384 h, well past them, but its profile — and so its snow-level line and phased bars — only to +240 h; hours beyond that carry precipitation but no phase, drawn unclassified. Selected cell -36.500, 148.500 on a 0.25° grid · Wed 30 0400hrs AEST · 1800Z. Its architecture has not been verified against NOAA documentation, so it is named only as NOAA publishes it.

NOAA HGEFS 0.25° is NOAA's hybrid AI-and-physics ensemble, and this line is its published ensemble mean — not a run, and not a member. Read it as the centre's own summary of members that disagree with each other, which is a systematically different quantity from a single forecast: on AIGEFS over the same window a sum of published means came to more than twice a sum of member medians, and both were correct answers to different questions. Three things about it are absences, and each is stated because each is permanent rather than a gap in this run. It publishes no individual members — the stream carries ensemble statistics only — so there is no P10–P90 beneath this line and there cannot be one. The spread it does publish is a standard deviation, and turning a mean and a standard deviation into a percentile range assumes the members are normally distributed about the mean; precipitation is bounded at zero and skewed, and where that assumption can be checked against real members it fails badly, so this page shows a mean with nothing around it rather than a band no member forecast. Its bars are unclassified, every one of them: the stream does publish the pressure levels the wet-bulb method needs, but a snow level derived from an ensemble MEAN profile is not any member's snow level — averaging temperature and humidity across members that disagree about the pattern yields an atmospheric state none of them forecast — so no phase is claimed and no snow-level line is drawn for this track. And it publishes no snowfall field, so there is no native SWE figure beside its total and there never will be. Bars are drawn across the 6 hour spans the accumulations actually cover, at each span's mm/h rate, at NATIVE cadence; the total is over this chart's hours only. This stream stops at +240 h — its own hard cap rather than a choice made here. Selected cell -36.500, 148.500 on a 0.25° grid · Wed 30 0400hrs AEST · 1800Z. Its architecture has not been verified against NOAA documentation, so it is named only as NOAA publishes it.