Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
387 FXUS66 KSTO 100830 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 130 AM PDT Wed Jul 10 2024 .SYNOPSIS... Hot and dry weather will continue this week with Moderate to Extreme HeatRisk persisting across much of the region. Elevated fire weather concerns will also continue. Cooler this weekend into early next week. && Key Points - Long-duration, dangerous heat event persists this week. - Very hot today into Friday, followed by some cooling over the weekend into next week .Discussion... Marine layer has deepened to around 1800 ft per Fort Ord Profiler since this afternoon with a moderate to strong Delta breeze. GOES-16 night fog product showing stratus to near Cordelia at this time. Current morning temperatures running near the same or a little cooler than 24 hrs ago. Delta breeze weakens later this morning as heights/thicknesses rise over interior NorCal in response to upper high over the Great Basin building westward. Triple digit heat returns throughout the Central Valley today, and much of the Delta, with NBM forecasting highs from around 105 to 113, hottest in the N Sac Valley. As result, widespread major heat risk expected today in the Central Valley and thermal belts of the foothills, with moderate heat risk near the Delta and in the mountains. AMS continues to warm Thursday under strong subsidence with most locations peaking in heat tomorrow. Highs from 110 to 115 will be common in the Central Valley. Highs expected to remain mainly below record values, but could tie or exceed records in portions of the N Sac Valley. Widespread Major to locally Extreme Heat Risk anticipated over interior NorCal. Models slowing with northward drift of cut-off low off the SoCal coast Friday. As a result, little change expected Friday over interior NorCal with max T`s mainly near or only a few degrees lower. Minor synoptic cooling with deepening marine layer and increased onshore flow expected Saturday as offshore cut-off low drifts north to around 150 NM west of KMRY. Around 4 to 8 degrees of cooling expected with mid to upper 90s in Delta breeze influenced areas. Highs in the Central Valley expected around 100 to 110 with mostly 80s to 90s for the mountains and foothills. Low could provide enough synoptic lift to allow for isolated deep moist convection over higher elevations of the N Sierra Nevada Saturday afternoon. Latest HeatRisk: wpc.ncep.noaa.gov/heatrisk/ Heat Safety Tips: weather.gov/safety/heat PCH && .EXTENDED DISCUSSION (Sunday THROUGH Wednesday)... Cut-off low off the CA coast progged to continue to drift north Sunday as it opens to trough. Cooling influence will continue Sunday with mid to upper 90s forecast in the S Sac/N San Joaquin Valleys. Elsewhere in the Central Valley, NBM showing highs around 100 to 104. Weak upper troughing looks to remain along with West Coast early next week as upper high remains farther east near the 4 corners. As a result, high temperatures remain a few degrees above normal through the extended period. && .AVIATION... VFR conditions over interior NorCal next 24 hrs. Sfc wind mainly below 12 kts except vcnty of Delta SWly sfc wind 15-20 kts at times. && .STO WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 8 PM PDT Friday for Central Sacramento Valley-Motherlode-Mountains Southwestern Shasta County to Western Colusa County-Northeast Foothills/Sacramento Valley-Northern Sacramento Valley-Northern San Joaquin Valley- Shasta Lake Area / Northern Shasta County-Southern Sacramento Valley. Heat Advisory until 8 PM PDT Friday for Burney Basin / Eastern Shasta County-Carquinez Strait and Delta-West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park. && $$