Late-September Tasman System
1 resort in the path, 30cm at the biggest. Watching — the models see it but do not yet agree closely.
+35CM
Predicted at Whakapapa
19–56cm across the models
Storm
Sep 28–30
1 resort in the path
Peak
Sep 30
26cm at Treble Cone
Predicted
35cm
Whakapapa · 19–56cm across the models
Confidence
Watching
Updated
Sep 27, 00:30 UTC
SnowSure Forecaster
Written from the blend and the model spread · updated Sep 27, 00:30 UTC
Current prediction: 30cm for Treble Cone between 2026-09-28 and 2026-09-30, 30cm our central figure. The biggest day is 2026-09-30 at 26cm. Treble Cone is the only resort clearing our threshold so far. Confidence is watching: the signal has crossed our threshold but the models still disagree on how much. These figures are re-read from the latest model blend; each entry in the log keeps what we said at the time.
Forecast log
Every entry, newest first. Nothing is overwritten.
- Day 7·Sep 27·Likely·35cmLanded
Late-September Tasman System: 34.6–33.1cm for Whakapapa and Tūroa
The window opened today. Final prediction: 34.6cm for Whakapapa and 33.1cm for Tūroa over the window from 2026-09-27 to 2026-09-29. Whakapapa is expected to see a range of 19.4–55.5cm, with the biggest day on 2026-09-27 at 29.6cm. Tūroa's totals range from 11.6–58.3cm, also peaking on 2026-09-27 with 27.5cm. Since day 1, the top total has decreased by 7.9cm, and the window start has shifted one day later. Confidence remains likely, and we are tracking on schedule.
Window Sep 27–29 · Whakapapa
- Day 6·Sep 24·Likely·35cm(-8)
Late-September Tasman System: 34.6–33.1cm for Whakapapa and Tūroa
Day 6: the window has shifted one day later, but totals remain strong. We now anticipate 34.6cm for Whakapapa and 33.1cm for Tūroa over the window from 2026-09-27 to 2026-09-29. The biggest day for both resorts is expected to be 2026-09-27, with Whakapapa receiving 29.6cm and Tūroa 27.5cm. Confidence in these totals is still likely, and the trend remains on track. As we approach the event, we will closely monitor any changes in the models that could affect timing or amounts.
Window Sep 27–29 · Whakapapa
- Day 5·Sep 23·Likely·43cm(-9)
Late-September Tasman System: 42.5–41.9cm for Whakapapa and Tūroa
Day 5: the window has slid a day later, and totals are down 9.4cm since the previous entry. For the upcoming window from 2026-09-26 to 2026-09-29, we predict 42.5cm for Whakapapa and 41.9cm for Tūroa, with the biggest day expected on 2026-09-27 at 26.9cm and 24.3cm, respectively. Confidence remains likely, but the trend is weakening, so we will continue to monitor the models closely as we approach the event.
Window Sep 26–29 · Whakapapa
- Day 4·Sep 22·Likely·52cm(+11)
Late-September Tasman System: 51.9–49.7cm for Whakapapa and Tūroa
Day 4: totals up 10.7cm since the previous entry and the window held. We are now predicting 51.9cm for Whakapapa and 49.7cm for Tūroa over the event window from 2026-09-25 to 2026-09-29. The biggest day for both resorts is expected to be 2026-09-27, with Whakapapa seeing 38.5cm and Tūroa 35.8cm. Confidence remains likely, and the trend is on track. As we approach the window, we will be monitoring any shifts in the storm's intensity and timing, which could impact these totals.
Window Sep 25–29 · Whakapapa
- Day 3·Sep 21·Likely·41cm(-9)
Late-September Tasman System: 41–40cm for Whakapapa and Tūroa
Day 3: totals down 8.6cm since the previous entry, but the window remains unchanged. For the upcoming storm window from 2026-09-25 to 2026-09-29, we are now predicting 41.2cm for Whakapapa and 40.7cm for Tūroa. The biggest day is expected to be 2026-09-27, with Whakapapa seeing 29.5cm and Tūroa 28.4cm. Confidence in these totals is likely, and the trend is strengthening as we approach the event. We will continue to monitor the models for any shifts in timing or amounts.
Window Sep 25–29 · Whakapapa
- Day 2·Sep 20·Likely·50cm(+5)
Late-September Tasman System: 49.6–49.8cm for Tūroa and Whakapapa
Day 2: totals up 4.6cm since the previous entry, with the window holding. For the upcoming storm window from 2026-09-25 to 2026-09-29, we are now predicting 49.8cm for Tūroa and 49.6cm for Whakapapa. The biggest day is expected to be 2026-09-27, with Tūroa seeing 18.3cm and Whakapapa potentially reaching 20.6cm. Confidence remains likely, and the trend is strengthening for both resorts. As we approach the event, we will continue to monitor model outputs for any shifts in timing or totals.
Window Sep 25–29 · Tūroa
- Day 1·Sep 19·Likely·45cmFirst prediction
Late-September Tasman System: 45–95.6cm for Whakapapa
The prediction for the window from 2026-09-25 to 2026-09-29 indicates Whakapapa could see 45.2cm, with a range of 9–95.6cm, while Tūroa may receive 40.4cm, ranging from 1.1–84.7cm. Current patterns suggest a weakening trend, which may impact snowfall totals. Among the resorts, Whakapapa appears to have a more favorable outlook, likely to receive the most significant totals, particularly on 2026-09-27 with a peak of 29.5cm. Tūroa's confidence remains lower as we continue to monitor the situation. A shift in the overall weather pattern could change these predictions significantly.
Window Sep 25–29 · Whakapapa
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 1,952 m
—cm snow
no daily data
No daily series on file for these resorts yet.
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.
