Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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511 FXUS66 KMTR 301117 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 417 AM PDT Tue Apr 30 2024 ...New AVIATION, 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. && .SHORT TERM... (Today and tonight) Issued at 203 AM PDT Tue Apr 30 2024 Dry conditions prevailing with high pressure from the offshore waters to far northern California and the Pacific Northwest. Gusty northwest winds continue over the coastal waters. Forecast highs today 60s near the coast and bays to the 70s inland. && .LONG TERM... (Wednesday 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... (12Z TAFS) Issued at 416 AM PDT Tue Apr 30 2024 Generally VFR through the TAF period with patchy stratus in the higher elevations. Breezy westerly winds building through the day with gusts somewhat less intense than seen yesterday. LLWS concerns start to emerge early Wednesday morning, towards and after the end of the TAF period, primarily for the East Bay and eastern North Bay. Vicinity of SFO... VFR through the TAF period. Breezy west-northwest winds building through the day. As of now, winds expected to gust up to 30 knots this afternoon and evening. Not expecting gusts above 35 knots at this time, but will monitor the evolution of the situation. SFO Bridge Approach... Similar to SFO. Monterey Bay Terminals... Not expecting any more ceilings to develop at MRY for the rest of the morning, and a low confidence (10-20% probability) that a patch of MVFR stratus forms over the northern Santa Lucias late this evening into Wednesday morning and then impacts the terminal. Otherwise, generally VFR through the region with breezy onshore flow developing this afternoon and evening. && .MARINE... (Today through Sunday) Issued at 416 AM PDT Tue Apr 30 2024 A strong northerly pressure gradient continues to produce hazardous gale force wind gusts through early Friday. Gale force gusts of 40 to 45 knots are possible over the outer waters and portions of the immediate coast near Point Reyes and Point Sur. The strong winds will result in fresh steep wind waves with heights reaching 10 to 12 feet. Conditions will gradually improve late in the week into next week. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 3 PM this afternoon to 3 AM PDT Wednesday for SF Bay N of Bay Bridge. Small Craft Advisory from 9 AM this morning to 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 Pt Arena to Pt Reyes 0- 10 nm. Small Craft Advisory until 3 AM PDT Wednesday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory from 3 PM to 9 PM PDT Wednesday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Gale Warning until 9 PM PDT Wednesday for Pt Pinos to Pt Piedras Blancas 0-10 nm. Gale Warning until 3 AM PDT Thursday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Canepa LONG TERM....Canepa AVIATION...DialH MARINE...DialH 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