Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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084 FXUS66 KMTR 201618 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 918 AM PDT Fri Sep 20 2024 ...New UPDATE, MARINE... .SYNOPSIS... Issued at 350 AM PDT Fri Sep 20 2024 Warmer temperatures today mark the beginning of a steady warming trend that will persist through the weekend into the beginning of next week. Moderate heat risk conditions are still possible for many interior locations Monday and Tuesday, but forecast trend has been slightly cooler. && .UPDATE... Issued at 912 AM PDT Fri Sep 20 2024 Stratus is just starting to break up across the region, with the interior East Bay and the Carmel Valley clearing out the most visibly on satellite imagery. Some coastal drizzle was observed earlier this morning, with accumulations ranging from a trace to a few hundredths of an inch. Progressive clearing of stratus is expected inland with the immediate coast and parts of Monterey Bay remaining socked in through the day. No updates to the forecast at this time. DialH && .SHORT TERM... (Today and tonight) Issued at 350 AM PDT Fri Sep 20 2024 Low stratus clouds have filled in along the coastline and interior gaps and valleys overnight and will begin to erode by mid/late morning except along the immediate coastline, especially Monterey Bay, where the marine boundary layer is reestablished with light onshore flow throughout the day. Gradual but steady H50 height increases in the wake of the upper low moving inland over SOCAL this afternoon will lift temperatures up about 5 degrees over inland locations from yesterdays high temperatures. High pressure continues to build offshore tomorrow, driving temperatures warmer on Saturday to around normal values for this time of year. && .LONG TERM... (Saturday through Thursday) Issued at 350 AM PDT Fri Sep 20 2024 Temperatures will gradually warm through the weekend into the beginning of next week. The forecasted max temperatures have trended slightly cooler but moderate heat risk across many inland locations Monday and Tuesday may still lead to the need for a Heat Advisory for those two days. There is poor consensus for the evolution of the synoptic pattern west of the Rockies for the first half of next week, as a weak upper level low develops off the coast of SOCAL. Nonetheless, temperatures moderate somewhat for the second half of next week from Monday and Tuesdays peak. We appear to remain dry through the extended forecast after some welcomed rainfall over southern Monterey County yesterday. && .AVIATION... (12Z TAFS) Issued at 404 AM PDT Fri Sep 20 2024 Stratus and fog /VLIFR-IFR-MVFR/ are moving inland on onshore winds this morning. Stratus and fog mixing out back to near the coast and bays by late morning and afternoon today. Vicinity of SFO...IFR prevailing to 1700z today, MVFR 1700z to 1830z today then VFR. IFR returning late tonight. West to southwest wind 5 to 15 knots. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VLIFR-IFR due to stratus and fog this morning, conditions improving to MVFR-VFR by late morning and afternoon today. MVFR-IFR in stratus and fog returning tonight. Onshore winds mainly 5 to 15 knots. && .MARINE... (Today through Wednesday) Issued at 912 AM PDT Fri Sep 20 2024 Moderate northwesterly winds continuing through Monday, then decrease to become gentle towards Tuesday. Seas will continue to build through the weekend, with wave heights up to 13 feet in the far northern outer waters as large, and shorter period northwesterly swell continues to move into the waters. Seas begin to abate Tuesday through the end of the forecast period. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 9 PM PDT Saturday for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...JM LONG TERM....JM AVIATION...Canepa MARINE...AC Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea