September Update - Winter 25/26 Season Snowfall Outlook Data
September 5th, 2025 β ECMWF Seasonal Model Update Todayβs ECMWF seasonal run keeps the weak La NiΓ±a in play a bit longer. Instead of fading quickly, the signal now holds through at least January, with neutral conditions not expected until mid to late February. Hereβs what the maps are showing: - NovβDecβJan: Greens light up across northern California and into the Sierra β often a sign of more storm action and a better shot at building early season snowpack. - JanβFebβMar: More green, though a shade lighter. Thatβs still a positive signal for a full seasonβs worth of snowfall. Yes, this far out weβre in βfantasy land,β but green is always the color we want to see. Take a look at the ECMWF maps below β green shades mark wetter than normal trends, while brown shades point to drier conditions. September runs are a key checkpoint. If the Sierra stays painted green again in Octoberβs update, confidence builds for a solid and steady winter. For now, itβs encouraging to see the signal lean our way. β Snowman π Follow the Mammoth Weather Story here: https://www.mammothsnowman.com/mammoth-mountain-weather-forecast/