Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
469 FXUS66 KSTO 072100 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 200 PM PDT Fri Jun 7 2024 .SYNOPSIS... Slightly cooler but still above normal temperatures over 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. 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 Monday)... Current GOES-West visible satellite imagery shows clear skies and abundant sunshine over much of interior northern California on this Friday afternoon, with the exception of some cumulus clouds that are developing over the Coast Range and southern Cascades. Temperatures are currently trending approximately 2 to 10 degrees cooler than this time yesterday afternoon, valid at 145 PM PDT as upper level ridging continues to shift eastward, and southwest flow influences the region. Forecast highs for this afternoon are in the low 100s for the northern and central Sacramento Valley, with sub-100s elsewhere. Increased onshore flow will be aiding in keeping temperatures cooler in the Delta and vicinity. There is a slight chance for a brief shower or thunderstorm this afternoon, with a 10-15% probability, mainly over the southern Cascades. For this weekend, slightly cooler but still above normal temperatures are forecast. Mainly Minor HeatRisk is expected, with just some isolated Moderate HeatRisk. 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. Additionally, a weak trough is expected to travel through the flow pattern Saturday into Sunday, bringing the potential for isolated high elevation mountain shower or thunderstorm chances in the afternoon or evening, mainly on Saturday where there is a 15-25% probability. A warmup is then expected to early next week, with Moderate HeatRisk returning on Monday, and localized Major HeatRisk in the northern and central Sacramento Valley. The warmup continues into part of the extended forecast period as well. Additionally, 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 (Tuesday THROUGH Friday)... Ensemble guidance and cluster analysis generally indicate quiet weather over the extended forecast period, with ridging creeping in from the eastern Pacific and a closed low over southern California mid-week. For much of the Valley on Tuesday and Wednesday, there is a 55 to 85 percent probability of high temperatures reaching or exceeding the 100 degree mark once again. This translates to Moderate HeatRisk for most of the area, with areas of Major HeatRisk in the northern and central Sacramento Valley on Tuesday and Wednesday. Ensembles and clusters then suggest some cooling for late week, although there is still somewhat of a decent spread in forecast highs. Current forecast has HeatRisk decreasing to mainly Minor with areas of Moderate for Thursday and Friday. && .AVIATION... VFR conditions prevail over interior NorCal over the next 24 hours. Southwest wind gusts of 15-25 kts in the Delta through 12Z Saturday, and in the Sacramento Valley through around 06Z-09Z Saturday. Northwest wind gusts 15-20 kts in the northern San Joaquin Valley through 06Z Saturday. Slight chance of high elevation mountain shower/thunderstorm through 03Z Saturday and again after 18Z Saturday. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$