Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
076 FXUS66 KSTO 130939 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 239 AM PDT Thu Jun 13 2024 .SYNOPSIS... Temperatures will trend cooler the rest of this week and into next week. Isolated shower/thunderstorms over the Sierra Crest south of Highway 50 Thursday afternoon. Elevated fire weather conditions this weekend into early next week. && .DISCUSSION... Key Points - Cooler today, with closer to normal temperatures and Minor HeatRisk through the weekend and into next week - Slight chance of shower/thunderstorm over the Sierra Crest south of Highway 50 Thursday afternoon - Elevated Fire Weather Conditions later this weekend into early next week from gusty northerly wind and low RH - Local waterways are still running cold and fast from snowmelt Short-Term Discussion (Today THROUGH Sunday)... Current GOES-West satellite imagery shows mostly clear skies across interior northern California early on this Thursday morning. Temperatures are currently trending approximately around 5 to 15 degrees cooler than this time yesterday morning, valid at 230 AM PDT. This cooldown is most noticeable in the vicinity of the Delta and adjacent Valley locations, as a strong Delta Breeze is being observed. Cooler daytime high temperatures are also expected across the area today as ridging shifts eastward and a low pressure area approaches over the Gulf of Alaska, with locally breezy onshore flow. Forecast highs will be closer to normal for mid June climatology today and through the weekend, with 80s-90s in the Valley, 80s to around 90 in the foothills, and 60s to 80s for the mountains. There is also a slight (10-20%) probability of isolated shower/thunderstorms over the Sierra Crest south of Highway 50 this afternoon and evening. Over the weekend, increased northerly flow and low relative humidity will bring elevated fire weather conditions to the Valley. The National Blend of Models (NBM) suggests a 20-60% probability for wind gusts of 40 mph or higher, strongest on Sunday, and in the northern and central Sacramento Valley. Daytime relative humidity is projected to be in the 10-20% range, with overnight recoveries in the 30-50% range Saturday night. The gusty northerly winds and low relative humidity will lead to elevated fire weather conditions this weekend, continuing into early next week. && .EXTENDED DISCUSSION (Monday THROUGH Thursday)... Ensembles and clusters show upper level low dropping southeast from the Pacific Northwest into the Great Basin Region Monday through Wednesday. This will bring cooler temperatures and breezy winds to NorCal early next week. Ensembles continue to hint at a prolonged period of north winds with gusts in the 20-30 mph range, this combined with relative humidity levels in the teens will likely lead to a period of enhanced fire weather concerns over much of the northern Sacramento Valley. We will have to also keep an eye out for any increased thunderstorm chances over Shasta county and the northern Sierra in ensembles, as would be expected with an anomalous trough of this type this time of year. && .AVIATION... VFR conditions over interior NorCal next 24 hours. Southerly surface winds up to 20 kts in the southern Sacramento Valley, and northwesterly wind gusts up to 20 kts northern San Joaquin Valley. Surface winds 15-25 kts vicinity Delta with gusts up to 30 kts. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$