Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
941 FXUS66 KSTO 250834 CCA AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 125 AM PDT Wed Sep 25 2024 .Synopsis... Cooler high temperatures today and Thursday with breezy onshore winds. Warmer and drier conditions return Friday through early next week. && .Discussion... Mostly clear skies and upper 60s to mid 70s temperatures around interior NorCal this early Wednesday morning. Temperatures will cool today, as a closed low phases with a trough in the PacNW and heights will fall as a result. High temperatures in the late afternoon are expected to be 10+ degrees cooler than yesterday & enhanced onshore flow will begin to develop later this morning. Latest National Blend of Models (NBM) probabilities of wind gusts exceeding 30 mph today are around 60-90% in the Delta and around a 30-60% chance of 25 mph wind gusts across the rest of the area. Better probabilities for 25 mph wind gusts are along the I-5 corridor from Woodland into Red Bluff. Humidity values will also increase today, as the cooler and moist air intrudes into the Valley. Only a slight warmup is anticipated on Thursday, as broad upper level ridging starts build in the Four Corners region and the weak closed low off the Baja California coast retrogrades towards the west. This upper level pattern will lead to northerly winds developing Thursday and Friday, with drier conditions overtaking the area on Friday. With daytime humidity values in the teens to low 20s, elevated fire weather conditions will prevail on Friday. Along with the drier air, Friday our area will warmup as the upper level air pattern becomes somewhat stagnant and zonal, with temperatures in the mid 90s to triple digits in the northern Sacramento Valley. Saturday, high temperatures will remain similar to Friday`s, with only modest cooling in the Delta anticipated as broad upper level troughing will develop offshore. Winds should return to a more diurnal pattern across the region. Daytime humidities will still be relatively dry (15-25%) across the area, but the northerly winds will have subsided with wind speeds generally around 10 to 15 mph. Wood && .EXTENDED DISCUSSION (Sunday THROUGH Wednesday)... Heights trend up Sunday into Tuesday as EPAC high and Desert SW High gradually merge over NorCal. Closed upper low remains well south of the forecast area. Slightly cooler Wednesday as upper ridging weakens in response to short wave trough progressing across the northern states. High temperatures forecast to be slightly above normal with moderate heat risk into Tuesday, then near normal Wednesday. Locally gusty north to east wind at times Sunday into Tuesday will result in periods of elevated fire weather conditions. && .AVIATION... VFR conditions over interior NorCal next 24 hrs. Sfc wind mainly at or below 12 kts except vcnty of Delta, SWly sfc wind 15-25 kts. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$