Late-September Tasman System
1 resort in the path, 2cm at the biggest. Watching — the models see it but do not yet agree closely.
+2CM
Predicted at Treble Cone
0–7cm, models far apart
Storm
Sep 28–30
1 resort in the path
Peak
Sep 30
2cm at Treble Cone
Predicted
2cm
Treble Cone · 0–7cm, models far apart
Confidence
Watching
Updated
Sep 19, 06:30 UTC
SnowSure Forecaster
Written from the blend and the model spread · updated Sep 19, 06:30 UTC
We are watching a significant system for New Zealand and Australia between 2026-09-28 and 2026-09-30. Treble Cone carries the biggest signal at 1.7cm over 2026-09-28 to 2026-09-30. At Treble Cone the freezing level on the snow days sits above the summit, so treat those totals with caution. The call changes if model agreement loosens, the window slides later, or the freezing level trends higher.
Snow by day
Sep 27 – Oct 1, with a day either side. For each resort: where the freeze line sits against the mountain, then what falls — snow in cm, rain in mm — and the day read from those two numbers.
Treble Conebase 1,200 m · summit 2,088 m
2cm snow
Modelled at the summit, 2,088 m · snow to the base
linem
/ raincm · mm
Sun
Sep 27
Snow
Mon
Sep 28
Dry
Tue
Sep 29
Dry
Wed
Sep 30
Snow
Thu
Oct 1
Snow
snow Wed
snowrain low, snow highraindryThe dots are the freeze line — the height where rain turns to snow. Solid: straight from the models. Hollow: estimated from temperature. Above the summit line it rains on the whole mountain; below the base line it snows all the way down. Blue bars are snow in cm, amber bars rain in mm; the totals above are their sums.
Rain / snow line
Base to summit for each mountain, with the snow line cut across them.
The system
700mb flow — where the storm is, and what is steering it. Pins sized by forecast total.
72-hour snowfall forecast for the same window.
In the path
Forecast, not observation — none of this has fallen yet. Totals are across the window. We will post what fell when the window closes.
Last updated 2026-09-19 06:30 UTC. SnowSure scans a blend of seven weather models twice daily and flags systems clearing 30cm over 72 hours, three to fourteen days out. This watch opened on 2026-09-19 with 30cm forecast at Treble Cone.
