Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
756 FXUS66 KSTO 011017 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 317 AM PDT Tue Oct 1 2024 .Synopsis... Hot weather continues through midweek with hottest temperatures today and tomorrow. A Heat Advisory is in effect beginning 11 AM Today until 11 PM Wednesday. Breezy north to east winds and low relative humidities will bring elevated fire weather conditions this morning. && .Discussion... Forecast remains fairly on track with widespread Moderate HeatRisk throughout the Valley with Major HeatRisk across the foothills today through Thursday afternoon. Hottest temperatures are forecasted today and tomorrow with afternoon highs from 95 to 105 with warm overnight lows in the 60s to mid 70s. As a result, a Heat Advisory has been issued from 11 AM Today to 11 PM Wednesday for the Carquinez Strait and Delta, Sacramento Valley, Northern San Joaquin Valley, and the foothills. Heat related illnesses will be possible, especially for groups sensitive to heat. Be sure to stay out of the sun during the hottest parts of the day if possible and stay hydrated! Combined with the hot weather, conditions will be dry throughout the forecast area with minimum relative humidities of 10-20% today and tomorrow, with marginal increases expected later this week. North wind gusts this morning remain on the weaker side and will be 10-20 MPH, strongest along the west side of the Valley. Through the middle of this week, we will see weak northerly winds each morning but remain below Red Flag Warning criteria. The pattern begins to shift on Thursday as onshore flow increases with an upper level trough dropping down from the Pacific NW although ridging in the southwest extends into Central CA. This will keep things warm in the afternoon but a weak Delta Breeze will help moderate heat impacts and cooler overnight lows. Afternoon remains above normal with Valley highs in the mid to upper 90s with upper 60s to upper 80s across the mountains and foothills respectively. && .EXTENDED DISCUSSION (Saturday THROUGH Tuesday)... Hot, dry weather looks to continue through the extended period as upper level ridging remains in place over Northern California. Ensemble guidance shows a slight breakdown in the ridge by the weekend which will translate to slightly cooler high temperatures. The National Blend of Models (NBM) currently projects highs in the low to mid 90s for the Valley, mid 80s to low 90s over the foothills, and 60s to mid 80s over the mountains. However, temperatures will still be 10-20 degrees above normal resulting in widespread Moderate HeatRisk across the Valley and foothills this weekend. Clusters hint at the possibility of a flattening of the ridge on Tuesday and the chances to see below to normal temperatures back across the area. There remains a wide spread of temperature outcomes next week, so stay tuned for more updates to the forecast. && .AVIATION... VFR conditions over interior Northern California for the next 24 hours. Northeasterly surface wind 15-20 kts are possible in the foothills and mountains until 17Z on Tuesday, and northwesterly surface wind up to 15 kts possible in the vicinity of the Delta until 19Z Tuesday, otherwise surface winds generally less than 12 kts for next 24 hours. && .STO WATCHES/WARNINGS/ADVISORIES... Heat Advisory from 11 AM this morning to 11 PM PDT Wednesday for Carquinez Strait and Delta-Central Sacramento Valley-Motherlode- Northeast Foothills/Sacramento Valley-Northern Sacramento Valley- Northern San Joaquin Valley-Southern Sacramento Valley. && $$