Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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237 FXUS66 KMTR 010357 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 857 PM PDT Tue Apr 30 2024 ...New UPDATE, MARINE... .SYNOPSIS... Issued at 133 AM PDT Tue Apr 30 2024 High pressure brings quiet weather and slowly warming temperatures this week. Breezy onshore winds will keep temperatures along the coast cooler however. Cooler and more unsettled conditions return this weekend into next week with light rain chances in the forecast. && .UPDATE... Issued at 856 PM PDT Tue Apr 30 2024 Relatively quiet weather as we transition from April into May. HREF continues to indicate minimal cloud cover overnight which will allow overnight temperatures to cool into the mid to low 40`s. Tomorrow`s temperature forecast looks to remain on track with inland highs in the low to mid 70`s and coastal highs in the upper 50`s to low 60`s. Gusty northwest winds gradually becoming more northerly will continue through the end of the work week. No updates needed to the forecast. This concludes April 2024. && .SHORT TERM... (This evening through Wednesday) Issued at 106 PM PDT Tue Apr 30 2024 Overnight temperatures are forecast to cool into the 40`s across much of the region with less cloud cover. However, areas around the Monterey Bay have the potential to see low clouds develop once again. Once any low clouds that do develop dissipate, temperatures will begin to warm and are likely to reach into the 60`s near the coast (70`s in places such as Santa Cruz) with mid-to-upper 70`s inland. && .LONG TERM... (Wednesday night through Monday) Issued at 203 AM PDT Tue Apr 30 2024 Dry conditions prevailing through mid-week. A slowly retrograding long wave trough along the West Coast varies in strength late week and early next week. There is a large difference between recent GFS (wet) and ECMWF (not nearly as wet as the GFS) in calculating the trajectory/progression of a low pressure system moving through the long wave trough, now well within 120 hours (5 days) forecast. QPF differences are showing up in the GEFS and EPS as well, though recent EPS have increased a little. As of current, it remains a low confidence forecast from a global model forecast perspective. Given the model forecast trajectory of the low pressure system is from near the Bering Sea/Aleutians southeastward across the Pacific (and surface high pressure over the Pacific retrogrades) where below normal sea surface temperatures exist including a negative phase Pacific Decadal Oscillation (PDO) i.e. the potential forward slowing due to local surface heating is reduced therefore the quicker arriving QPF in the GFS solution may not be that far off if development much closer to our forecast area verifies. The northern hemispheric pattern remains active with the current number of long wave troughs reflecting a winter-like circulation. Stay tuned to latest forecast updates, as currently advertised the official forecast shows potential for showery, cool weather this weekend. Planning travel to the mountains? This pattern has potential for snow accumulations, it`s a good idea to monitor the latest forecasts. Per 30 year climatology we are of course past peak cool season rainfall, however it can still rain in May in the Bay Area and north Central Coast. Recalling a Lead Forecaster here years ago mentioned it`s always a good idea to carry chains in case needed (for Sierra Nevada travel) through Memorial Day. July climatologically is our driest time of year since by then the jet stream has reliably weakened and returned northward and high pressure often sets up. && .AVIATION... (00Z TAFS) Issued at 500 PM PDT Tue Apr 30 2024 VFR through the TAF period. Strong and gusty surface winds continue into the early night. Winds slowly ease near the surface into the night, but winds winds aloft turn more northerly and increase to around 25-40 kts from roughly 1500ft to 2000ft AGL. This will introduce directional and speed shear for most terminals tonight, especially the North Bay. It is not until the mid to late morning of Wednesday that wind shear diminishes. Breezy winds build in Wednesday afternoon. Vicinity of SFO...VFR through the TAF period. Strong northwest winds with around 30 kt gusts linger into the late evening before becoming lighter. Expect winds around 2000ft AGL to become more northerly and gain strength, leading to LLWS concerns. These concerns ease into mid Wednesday morning as winds a loft decrease. Breezy northwest winds build into Wednesday afternoon and last into the night. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR through the TAF period. Breezy winds last into the night before reducing. Winds aloft over MRY stay strong and turn more Northerly overnight, leading to LLWS concerns, while SNS looks to stay sheltered. Expect shear concerns to ease into mid Wednesday morning, followed by a breezy afternoon. && .MARINE... (Tonight through next Monday) Issued at 856 PM PDT Tue Apr 30 2024 Breezy and gusty winds last through Friday, with gale force gusts of 40 to 45 knots possible in the outer waters through much of the week. The strong winds will result in hazardous seas and steep wind waves with significant wave heights reaching 10 to 14 feet in the outer waters. Conditions will gradually improve over the weekend and into next week as winds begin to ease. Chances of rain begin early Saturday as a trough descends over the region. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 3 AM PDT Wednesday for Mry Bay. Small Craft Advisory from 9 AM to 9 PM PDT Wednesday for Mry Bay. Gale Warning until 3 AM PDT Wednesday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Gale Warning until 3 AM PDT Thursday for Pt Arena to Pt Reyes 10- 60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm. Gale Warning until 9 AM PDT Thursday 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