Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
732 FXUS66 KSTO 142119 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 219 PM PDT Fri Jun 14 2024 .SYNOPSIS... Critical fire weather conditions likely Saturday night through Sunday night across the Sacramento Valley due to gusty northerly winds and low relative humidity. Seasonable temperatures and dry conditions continue over the next several days. && .DISCUSSION... Key Points - A Red Flag Warning is in effect from 11 PM Saturday - 8 PM Sunday across the majority of the Sacramento Valley due to low daytime relative humidity, gusty northerly winds, and poor overnight recoveries. - Northerly winds continue early next week maintaining some locally elevated fire weather conditions Monday and Tuesday Short-Term Discussion (Today THROUGH Monday)... Afternoon GOES-18 Satellite imagery reveals mostly clear skies across interior NorCal. Temperatures are currently running in the upper 70s to upper 80s across the Valley and mid 60s to upper 70s in the Foothills/mountains. Temperatures are forecast to reach the low to mid 90s for the Valley as we approach the maximum of daytime heating. As we move into the weekend, a trough will slide into the PacNW and introduce stronger pressure gradients around the area, which will increase northerly wind speeds across the Valley. The trough`s main moisture pool will be to the north of our area, so there is no precipitation expected in our region. On Sunday, the northwesterly flow will become stronger as the trough phases with a closed low in Canada, where our heights will be in a more northwesterly flow. Critical fire weather conditions are expected to develop late Saturday night through Sunday evening in the Valley due to gusty northerly winds and low relative humidity (RH) values. Strongest winds are expected in the western Sacramento Valley, where the National Blend of Models (NBM) is projecting around 20-45% probability of wind gusts reaching 40 mph. Recent NBM runs have backed off slightly on the sustained and gusty winds, however low RH values in the teens, along with poor overnight recoveries Saturday will still lead to critical fire weather conditions. These conditions have warranted a Red Flag Warning to be issued from 11 PM Saturday night through 8 PM Sunday, when the gustiest winds and lowest RH values are anticipated. Elevated fire weather conditions will persist into Monday, as we will keep breezy northerly winds and low RH values through the start of the work week. High temperatures during the short term are expected to remain seasonal,with highs in the mid 80s to low 90s today through Monday for the Valley. The trough aloft and onshore flow in the Delta will promote cooling overnight in the Valley, with low temperatures in the 50s to low 60s. && .EXTENDED DISCUSSION (Tuesday THROUGH Friday)... Ensembles and clusters show upper level low gradually weakening over the Great Basin Region through next week, bringing periods of breezy winds at times over interior NorCal. Periods of northerly winds may bring elevated fire weather concerns through early next week. NBM guidance depicts Valley high temperatures gradually climbing into the 90s mid to late next, with mid 80s to low 90s over the foothills. && .AVIATION... VFR conditions over interior NorCal next 24 hours. Southerly surface winds up to 20 knots in the southern Sacramento Valley, northwesterly winds up to 20 knots in the northern San Joaquin Valley until around 06Z Saturday. Onshore surface winds of 15-25 knots in Delta with isolated gusts up to 30 knots. && .STO WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from 11 PM Saturday to 8 PM PDT Sunday for 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 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. && $$