Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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803 FXUS66 KMTR 181624 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 924 AM PDT Wed Sep 18 2024 ...New UPDATE, MARINE... .SYNOPSIS... Issued at 1252 AM PDT Wed Sep 18 2024 Chance of scattered showers today, tapering off from north to south gradually through Thursday morning. A warming trend is on tap for the rest of the week with seasonal normal temps expected by the weekend. && .UPDATE... Issued at 924 AM PDT Wed Sep 18 2024 Precipitation over the region has been mainly across the northern Santa Cruz Mountains and into the East Bay with reports up to 0.06" at Rocky Ridge (RGEC1). However, expecting rain to increase over the North Bay in the next couple of hours as a rain band approaches the region. As the low pressure center remains offshore, rain is expected to be less widespread as once thought with the region picking up around a trace to a few hundredths of an inch through the afternoon and evening. That said, the forecast remains on track with no updates anticipated at this time. && .SHORT TERM... (Today and Thursday) Issued at 1252 AM PDT Wed Sep 18 2024 The next system is currently moving in, made noticeable by the influx of higher cloud cover through the evening. As of about midnight, the surface low was located just off the coast of Oregon. The low will move southward through this morning, bringing light rain chances to the Bay Area by mid-to-late morning. There is a slight chance (~15%) of thunder during this time period, mainly in the North Bay. As the low moves through, moisture wrapping around the back side will affect areas south of the Bay Area, including the Central Coast, by the middle of Thursday morning. There is also a slight chance of thunder here during this time. Though a small chance, there could be some terrain enhancement over the Santa Lucia, resulting in isolated, brief heavier rain than what will be seen elsewhere. Shower activity ends gradually Thursday evening as the low moves inland. && .LONG TERM... (Friday through Tuesday) Issued at 1252 AM PDT Wed Sep 18 2024 A warming trend will kick off Friday into the weekend as the upper low exits and confidence grows in an a broad upper level ridge situated off the west coast. Temperatures through the weekend are expected to be near seasonal normals. Warming continues into early next week where we will begin to see slightly above normal temperatures. && .AVIATION... (12Z TAFS) Issued at 452 AM PDT Wed Sep 18 2024 Mid-level clouds as well as IFR and MVFR CIGs are moving through the area and look to last through the morning with light rain expected in the mid to late morning. Pockets of drizzle and mist will affect the coast as well as the Bays and STS in the late night ahead of the rain chances and lingering slightly after. Winds stay light to moderate through the morning. Widespread VFR returns for the TAF sites into Wednesday afternoon, but status lingers on the immediate coast. Expect moderate winds to build into the afternoon and linger into the evening. Coastal cloud cover moves slightly early Wednesday evening, affecting both bays with IFR and MVFR CIGS, with low clouds becoming widespread later that night. Vicinity of SFO...MVFR CIGs and last into the late morning with some shower activity in the mid to late morning. Expect light winds to become more moderate in the afternoon. CIGs erode as winds build in the early afternoon. Winds will reduce slightly into Tuesday evening and MVFR CIGs return in the late evening and early night. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...MVFR/IFR CIGs with mist and drizzle ahead of light scattered showers in the to late mid morning. CIGs scatter and winds become more moderate into Wednesday afternoon as showers exit. MVFR CIGs return early Wednesday evening as winds reduce. && .MARINE... (Today through Monday) Issued at 924 AM PDT Wed Sep 18 2024 Northwesterly winds will become gusty across the outer waters by late Wednesday. Seas will be moderate, building to become rough in the outer waters by Thursday. Unsettled conditions will continue over the outer waters through the weekend. Showers continue over the coastal waters through this afternoon. There is up to a 12% chance for thunderstorms in the mid morning which could produce lightning, locally heavy rainfall, locally gusty winds. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 3 PM Thursday to 3 AM PDT Friday for Pt Arena to Pt Reyes 10-60 NM. && $$ UPDATE...RGass SHORT TERM...Behringer LONG TERM....Behringer AVIATION...Murdock MARINE...Kennedy 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