Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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154 FXUS66 KMTR 012356 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 456 PM PDT Wed May 1 2024 ...New AVIATION, MARINE... .SYNOPSIS... Issued at 107 PM PDT Wed May 1 2024 A ridge of high pressure will keep conditions mild to warm across the region throughout late week. Breezy onshore winds will keep temperatures cooler near the coast. Wet, unsettled conditions returning Friday night into Saturday, much cooler inland Saturday. Unseasonably cool daytime highs continuing into early next week then gradually warming by the middle of the week. && .SHORT TERM... (This evening through Thursday) Issued at 107 PM PDT Wed May 1 2024 Dry weather conditions prevail tonight with temperatures falling into the mid-to-upper 40`s to lower 50`s regionwide. Only expecting low clouds near the Monterey Peninsula, if at all, as dry conditions remain aloft. By sunrise, any low clouds that do develop with quickly dissipate. Thursday will see stronger northerly winds out over the ocean, peaks near the coast, and inland higher terrain with gusts up to 45 mph (gale force out over the ocean). Temperatures will likely reach the 60`s near the coast with mid-to-upper 70`s to near 80F inland. Again, clear sky conditions are expected to persist. && .LONG TERM... (Thursday through Tuesday) Issued at 133 AM PDT Wed May 1 2024 Dry Thursday and Friday, increasing clouds Friday night with rain developing over the North Bay, rain spreading southeastward across much of the rest of the forecast area Saturday. It`ll turn noticeably cooler especially inland Saturday with daytime highs Saturday 10F to 18F cooler inland compared to Friday`s forecast highs. In the last 12-24 hours global and mesoscale models are more in line focusing on the arrival of a cold core low pressure system from the Bering Sea/Aleutian Islands arriving in northern California Friday night and Saturday. The southeastward trajectory takes it across cooler than normal sea surface temperatures (negative phase PDO) at least somewhat minimizing maritime thermal modification along the way and for maintenance/development it`ll travel through a long wave trough on the West Coast. The low will brush by and tap higher levels of water vapor extending far north of Hawaii, however the low is forecast to move through our forecast area retaining a strong mid-latitude influence. Recent precipitable water values on the GFS have been 1.00" to 1.10" for Saturday, not far from the max moving average on Oakland upper air sounding climatology in early May. Model forecast rainfall amounts vary from 0.25" to 0.70" North Bay, 0.15"-0.25" low elevations to 0.40" hills/mountains elsewhere across the Bay Area to around 0.10" interior north Central Coast to 0.33" Big Sur Coast. Wet and cooler weather Saturday, gusty northwest winds over the coast temporarily subsiding with the passage of a surface cold front/trough. Dry weather returns Sunday. The surface pressure pattern looks favorable for gusty northwest winds redeveloping over the coastal waters beginning next Tuesday. Daytime highs gradually warming by the middle of next week. && .AVIATION... (00Z TAFS) Issued at 455 PM PDT Wed May 1 2024 VFR through the TAF period. Breezy and gusty surface winds continue into the early night. Winds slowly ease near the surface into the night, for APC and LVK winds aloft turn more northerly and increase to around 30-35 kts from roughly 2000ft AGL. This will introduce directional and speed shear for those terminals overnight. It is not until the mid to late morning of Thursday that wind shear diminishes. Gusty northwest winds build in Thursday afternoon. Vicinity of SFO...VFR through the TAF period. Gusty northwest winds with around 25 kt gusts linger into the late evening/early night before becoming lighter. Stronger northwest winds build into Wednesday afternoon, peaking around 18 kts and gusting to around 30 kts. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR through the TAF period. Breezy winds last into the late evening before reducing. Winds stay light to moderate through the night before breezy to gusty westerly winds arrive Thursday afternoon. && .MARINE... (Tonight through next Monday) Issued at 455 PM PDT Wed May 1 2024 Expect breezy and gusty winds continue through Friday, with gale force gusts of 40 to 45 knots possible in the outer waters. Strong winds will result in hazardous seas and steep wind waves with significant wave heights reaching 12 to 18 feet in the outer waters. Conditions gradually improve over the weekend and into next week as winds begin to ease. Rain chances begin early Saturday as a trough descends over the region. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay. Small Craft Advisory from 9 AM Thursday to 3 AM PDT Friday for Mry Bay. Gale Warning until 3 AM PDT Thursday for Pt Arena to Pt Reyes 0- 10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm. Gale Warning until 9 PM PDT this evening for Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 3 AM PDT Friday for Pigeon Pt to Pt Pinos 0-10 nm. Gale Warning until 3 PM PDT Thursday for Pt Arena to Pt Reyes 10- 60 NM. Gale Warning until 3 AM PDT Friday for Pigeon Pt to Pt Pinos 10- 60 NM. && $$ SHORT TERM...RGass LONG TERM....Canepa AVIATION...Murdock MARINE...Murdock 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