Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
831 FXUS66 KSTO 160930 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 230 AM PDT Mon Sep 16 2024 .Synopsis... Cooler unsettled weather thru mid-week with periods of showers and isolated thunderstorms. Dry and warmer weather returns late in the week into next weekend. && .Discussion... 557 DM upper low centered just NE of KEDU this morning is progged to continue to dig SSE today is it slowly begins to fill. Best chances for showers looks to be in the vicinity of low center and with wrap around moisture over the mountains. Isolated thunderstorms also possible over the mountains today in areas of higher CAPE. Snow levels remain at or above pass levels with local light accumulation`s possible in stronger cells. System has ushered in cooler air, and high temps today forecast to be upwards of 20+ degrees below normal. NBM predicting low to mid 70s for the Central Valley with 40s to 60s for the mountains and foothills. Primary upper low continues to fill tonight as it heads to SoCal while secondary low develops over the Great Basin. Lingering showers possible overnight, mainly over the Sierra Nevada with snow levels remaining at or above pass levels. Drier weather expected Tuesday with slight warming as weak short wave upper ridging moves through. Another short wave trough then progged to drop into West Coast long wave Tuesday night into Wednesday. This will bring another round of unsettled weather to interior NorCal. POPs increase from N to S Tuesday night with widespread threat of showers over the CWA Wednesday. Best instabilities depicted over the foothills and mountains for potential thunderstorms. This wave appears not as cold aloft as the system moving through today, and 5H cold core remains offshore through Wednesday. Thus bulk of precip in mountains expected to be liquid as snow levels remain well above pass levels. Upper low is progged to continue to dig south along the CA coast to near Point Conception by 12z Thu, then track eastward across CA. Precip threat continues over the Sierra Nevada Thursday while remainder of the CWA sees fair weather with warming as EPAC upper ridging begins to build inland. High temperatures Thursday climb back into the 80s for the Central Valley. && .EXTENDED DISCUSSION (Friday THROUGH Monday)... Dry weather expected through the extended forecast period as EPAC high extends inland over NorCal. AMS slowly warms into the weekend with high temperatures returning to near normal Sunday into Monday. && .AVIATION... In Central Vly, isold MVFR conditions possible at times in shra til 03z Tue, otherwise mainly VFR next 24 hrs. Sfc wind generally below 12 kts. Over fthls and mtns, areas MVFR/IFR possible next 24 hrs with trrn obscd. Isold tsra possible thru 03z Tue. Snow levels abv 7k ft. Lcl Wly sfc wind gusts to 20 kts possible over hyr trrn thru 00z Tue. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$