Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
279 FXUS66 KSTO 162030 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 130 PM PDT Sun Jun 16 2024 .SYNOPSIS... Critical fire weather conditions through early Tuesday across the Valley and Delta region due to gusty northerly winds and low relative humidity. Near normal to slightly below normal temperatures and dry conditions continue over the next few days before we see a return to warmer weather late in the week. && Key Points - A Red Flag Warning is in effect until 8 AM Tuesday across the majority of the Delta region, Valley, and adjacent foothills below 2000 ft, due to low daytime relative humidity, gusty northerly winds, and poor overnight recoveries. - Normal or near normal temperatures continue through most of the week, with a gradual warming trend late week into the weekend, and widespread Moderate HeatRisk expected on Friday. Short-Term Discussion (Today THROUGH Wednesday)... Broken high clouds cover much of interior NorCal this afternoon, but at the surface gusty winds and low relative humidities are creating critical fire weather conditions for elevations below 2000 ft. Due to the movement of the upper level trough, winds are currently gusting from the north around 15 to 30 mph in the Valley, and relative humidities are already as low as 10 to 20% in much of the area. Through early Tuesday, we`re expecting these conditions to continue, with gusts around 25 to 35 mph, and relative humidities in the teens. Overnight recoveries will be poor through Tuesday morning, with relative humidities only getting up to 25 to 45%. As such, a Red Flag Warning remains in effect through 8 AM Tuesday. Temperatures at least remain near or slightly below normal through Tuesday due to the trough; Wednesday however, temperatures begin to climb again. && .EXTENDED DISCUSSION (Thursday THROUGH Sunday)... Late in the week and through the weekend, upper level ridging causes the warming trend to continue, with widespread triple digits likely returning by Saturday. Widespread Moderate HeatRisk is expected Friday through Sunday, with areas of Major HeatRisk in the central Sacramento Valley and nearby foothills on Saturday. Probabilities of reaching at least 100 degrees are 50-85% throughout the Valley on Friday, and 70 to 90% on Saturday. On Sunday, temperatures look to hold steady rather than climbing further, but highs in the Valley will still be in the high 90s to low 100s, with foothill and mountain temperatures in the 90s and 80s respectively. && .AVIATION... VFR conditions over interior NorCal next 24 hours. In the Valley, widespread northwesterly surface wind up to 20 kts turning southwesterly in the vicinity of the Delta. In foothills and mountains, expect areas of northwest to northeast surface wind gusts up to 30 kts. && .STO WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 8 AM PDT Tuesday for Carquinez Strait and Delta-Central Sacramento Valley in Glenn, Colusa, Yuba, Northern Sutter, and Butte County Below 1000 Ft-Eastern Mendocino NF- Northern Sacramento Valley to Southern Tehama County Line Below 1000 Ft-Northern San Joaquin Valley in San Joaquin and Stanislaus Counties Below 1000 ft-Northern Sierra Foothills from 1000 to 3000 Ft. Includes portions of Shasta-Trinity and Butte Units-Northern Sierra Including Lassen NP and Plumas and Lassen NF/S West of the Sierra Crest (West of Evans Peak-Grizzly Peak- Beckworth Peak)-Southeast Edge Shasta-Trinity NF and Western Portions of Tehama-Glenn Unit-Southern Sacramento Valley in Yolo- Sacramento Far Western Placer, southern Sutter and Solano County Below 1000 Ft. && $$