Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
007 FXUS66 KSTO 061024 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 324 AM PDT Thu Jun 6 2024 .SYNOPSIS... Hot weather will continue again today, though with some slight cooling in the Delta and Sacramento metro area. Further cooling is expected across the area Friday into weekend. Triple digit heat returns again to north Sacramento Valley early next week. && .DISCUSSION... Key Points - An Excessive Heat Warning remains in effect through 8 PM PDT this evening across the Valley and adjacent foothills. - Areas of Major HeatRisk continue today, with Moderate HeatRisk by Friday; Triple digits in the Northern and Central Sacramento Valley and adjacent Valley foothills, less hot in the Delta and Sacramento metro area with highs in the mid to upper 90s. - Less hot this weekend, through with some areas of Moderate HeatRisk, mainly over the northern and central Sacramento Valley. Short-Term Discussion (Today THROUGH Sunday)... Temperatures early this morning remain quite mild, notably 84 degrees at Chico, Oroville, and 80 at Redding and Beale Air Force Base. A light Delta breeze is bringing a little relief for influenced areas, such as Davis at 68 and Fairfield at 69. There were a couple of record highs yesterday. These include Vacaville with a record of 104, breaking the old record of 103 set in 2002 and Marysville, tying the record of 104 set in 2002. Another day of hot weather is expected today with areas of Major Heatrisk values. The Delta breeze will provide some cooling to the Delta and adjacent Valley locations today, perhaps keeping Sacramento highs out of the triple digits (50% probability of 100 or more). The northern & central Sacramento Valley and northern San Joaquin Valley will see high temperatures about the same as on Wednesday, 101-106. An Excessive Heat Warning continues until 8 pm this evening. Afternoon convection today is expected to remain east of the Sierra Crest, with dry weather continuing across the area. There could be some cumulus buildups there and over the northern Coastal Range. A similar pattern is expected on Friday afternoon, with any shower and thunderstorm activity remaining east of the Crest. Friday and Saturday...The upper level ridge of high pressure continues to shift eastward and weaken in intensity as a low pressure trough extending southward from the Gulf of Alaska moves in and phases with low pressure off the Southern California coast. This will increase onshore flow and continue a cooling trend through the weekend. While highs will be less hot, temperatures will still be 2 to 8 degrees above normal for this time of the year. To view the latest HeatRisk, please visit www.wpc.ncep.noaa.gov/heatrisk/ To view current water temperatures, please visit www.cnrfc.noaa.gov && .EXTENDED DISCUSSION (Monday THROUGH Thursday)... Ensemble clusters continue to be in good agreement that a quiet pattern is expected next week, with some ridging over Pacific Northwest and northern Rocky Mountains with weak troughing to our south. The Northern Sacramento Valley could again see some areas with HeatRisk values, though the ECMWF Extreme Forecast Index (EFI) is showing just a slight signature for heat. The NBM has triple digit highs continuing in the northern and central Sac Valley through Wednesday with mostly 80s to lower 90s for the mountains and foothills. There is a trend in the NBM for slightly less hot weather for later in the week. An offshore closed upper low nudges slightly closer to the California coast midweek allowing for minor deepening of marine layer with additional slight cooling in Delta breeze influenced areas. In spite of this, high temperatures in the southern Sacramento Valley will remain around 10 degrees above normal. && .AVIATION... VFR conditions prevail over interior NorCal through the forecast period. Light to breezy south-southwest winds through the Sacramento Valley with northwest winds in the northern San Joaquin Valley, increasing after 18z with sustained surface wind up to 12 kts and localized gusts up to 15 kts. Through the Delta, west- southwest winds sustained 10-15 kts with gusts up to 20 kts after 18z. && .STO WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 8 PM PDT this evening for Carquinez Strait and Delta-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. && $$