September Update - Winter 25/26 Season Snowfall Outlook Data
September 5th, 2025 ā ECMWF Seasonal Model Update Todayās ECMWF seasonal run keeps the weak La NiƱa 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. Hereās what the maps are showing: - NovāDecāJan: Greens light up across northern California and into the Sierra ā often a sign of more storm action and a better shot at building early season snowpack. - JanāFebāMar: More green, though a shade lighter. Thatās still a positive signal for a full seasonās worth of snowfall. Yes, this far out weāre in āfantasy land,ā but green is always the color we want to see. Take a look at the ECMWF maps below ā 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 Octoberās update, confidence builds for a solid and steady winter. For now, itās encouraging to see the signal lean our way. ā Snowman š Follow the Mammoth Weather Story here: https://www.mammothsnowman.com/mammoth-mountain-weather-forecast/