Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
304 FXUS66 KSTO 080900 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 200 AM PDT Sat Jun 8 2024 .SYNOPSIS... Slightly cooler but still above normal temperatures continue through the weekend. Warmup expected early next week with Major HeatRisk for the northern and central Sacramento Valley. Isolated high elevation mountain shower/thunderstorm chances in the afternoon/evening hours today and Saturday. && .DISCUSSION... Key Points - Areas of Moderate HeatRisk for today; 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 80s to lower 90s. - Slightly cooler this weekend with just some localized Moderate HeatRisk, mainly over the northern and central Sacramento Valley. - Warm up expected early next week with well above normal temperatures through mid-week. Moderate HeatRisk returns to much of the Valley and foothills on these days, with areas of Major HeatRisk in the northern and central Sacramento Valley. Short-Term Discussion (Today THROUGH Tuesday)... For this weekend, slightly cooler but still above normal temperatures are forecast. Increased onshore flow is helping to keep temperatures cooler in the Delta and vicinity. Mainly Minor HeatRisk is expected across the area, with just some isolated Moderate HeatRisk, mainly around the northern Sacramento Valley. Valley high temperatures look to be in the upper 80s to mid 90s this weekend. With increased onshore flow, periods of breezy conditions are expected over the next few days, with onshore gusts of 15 to 25 mph in the afternoon and evening hours, primarily across the Delta and into the southern Sacramento Valley and northern San Joaquin Valley. A weak trough will pass through Saturday into Sunday, bringing the potential for isolated high elevation mountain showers or thunderstorms in the afternoon and evening. Instability is ample, with fairly high CAPE (Convective Available Potential Energy) levels over the northern Coastal Range and the northern Sierra south of Highway 50, but the best lift and moisture is to the north and east of the NWS Sacramento forecast area. The locations that could be impacted in our area include far northwestern Shasta County, Lassen National Park, and the Sierra Crest south of Highway 50. This is potential is mainly late Saturday, when there is a 15-25% probability. A warmup is expected for early next week, with widespread Moderate HeatRisk returning on Monday, and local Major HeatRisk in the northern and central Sacramento Valley. The NBM currently has Valley highs in the mid to upper 90s south of Interstate 80, with 100-104 to the north. The heat peaks on Tuesday, with Valley highs forecast 100-107, warmest over the northern Sacramento Valley. Widespread Major HeatRisk in the foothills and much of the Valley, though the Delta breeze could mitigate this to some extent for influenced areas. A reminder, area waterways continue to run fast and cold from snowmelt, creating dangerous conditions for those seeking relief in rivers and lakes next week. 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 (Wednesday THROUGH Saturday)... Closed upper low progged off the N Baja coast Wednesday with upper ridging along the W Coast. Low is forecast to gradually lift NE through SoCal late Thursday through early Friday as upper ridge shifts east. Upstream short wave trough then pushes through the W Coast Friday into Saturday with heights lowering over NorCal. Pattern change will result in a cooling beyond midweek with NBM advertising mostly 90s for the Central Valley Thursday into Saturday with mainly 70s and 80s for the mountains and foothills. Dry weather expected through the extended forecast period. && .AVIATION... VFR conditions over interior NorCal next 24 hrs exc lcl MVFR/IFR possible in stratus vcnty of Delta til 18z. Isolated tstm possible over cstl mtns btwn 20z-03z. Sfc wind mainly at or below 12 kts except vcnty of Delta SWly sfc wind 15-25 kts with gusts to 35 kts. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$