Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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819 FXUS66 KMTR 251058 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 358 AM PDT Tue Jun 25 2024 ...New AVIATION, MARINE... .SYNOPSIS... Issued at 315 AM PDT Tue Jun 25 2024 Elevated thunderstorms, with isolated to scattered coverage may produce lightning strikes capable of igniting grass fires today into the early evening hours. && .SHORT TERM... (Today and tonight) Issued at 315 AM PDT Tue Jun 25 2024 Lift associated with an upper level low approaching the Pacific Northwest over the next couple of days, is producing scattered showers over the open water to our west. Lightning even farther west and closer to the base of the trough can currently be seen tracking northeast overnight. The persistent ridging over the desert southwest will deflect the strongest energy associated with the trough to our north over the next twenty four hours. Scattered showers that develop this afternoon in an area of upper level diffluent flow (mainly across Monterey Bay and points north) will be capable of producing primarily elevated thunderstorms with limited coverage. There is some concern for any elevated storms producing lightning strikes across the northern half of our area being capable of igniting a grassfire. However, instability is weak with little to no CAPE evident. Later tonight into early Wednesday, upper level flow across our latitude becomes more zonal as the upper level low moves onshore into Washington state. Normal to slightly above normal max temperatures inland today will cool a few degrees tomorrow. && .LONG TERM... (Wednesday through Monday) Issued at 315 AM PDT Tue Jun 25 2024 The southern extent of an upper level trough axis will shift east across our area Thursday morning, as upper level flow shifts from zonal to northwest and shortwave ridging over the Pacific Northwest takes shape in the wake of the trough. The more amplified portion of the upper ridge will remain north of our area and another upper trough moves onshore over the weekend. Temperatures will cool nicely from today`s peak, for the end of the week into the weekend as cooler temperatures aloft spread over our region. A warmup looks likely for the beginning of next week as broad troughing is established across western CONUS. && .AVIATION... (12Z TAFS) Issued at 355 AM PDT Tue Jun 25 2024 The low chance-high impact threat remains for high-based convection through this evening. The latest lightning strikes were seen 300 miles off the coast of Point Piedras Blancas. Currently VFR at all terminals. VFR through the TAF period for APC, LVK, SJC, and STS. Overnight the Bay Area terminals of OAK and SFO will deteriorate to low-end MVFR while the Monterey Bay terminals of MRY and SNS will deteriorate to IFR. Winds will remain onshore through the TAF period. Vicinity of SFO...Currently VFR with westerly flow. Winds will prevail out of the west through the TAF period. A low-end MVFR ceiling will return to the terminal in the early morning hours of Wednesday, scattering out towards the end of the TAF period. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Currently VFR and calm at both terminals. Winds will prevail out of the west/northwest through the TAF period. Low confidence on if LIFR stratus will return to the terminals this morning, but moderate confidence in IFR stratus returning to both terminals overnight. && .MARINE... (Today through Sunday) Issued at 355 AM PDT Tue Jun 25 2024 Fair weather and moderate to fresh northwesterly breezes will prevail today. By Wednesday, surface high pressure over the Eastern Pacific Ocean builds, tightening the pressure gradient, resulting in strong northwesterly breezes through the end of the period. Significant wave heights will continue to abate below 10 feet through the period. && .FIRE WEATHER... Issued at 315 AM PDT Tue Jun 25 2024 There is a slight chance of thunderstorms this afternoon, with limited coverage. Given the elevated nature of any storms that may develop, any rainfall amounts, if any, will be light with some VIRGA possible and subsequent gusty winds. Any strikes that do occur may cause a fire start in the fine fuels. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 3 PM to 9 PM PDT Wednesday for Mry Bay- Pt Arena to Pt Reyes 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory from 9 AM to 9 PM PDT Wednesday for Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0- 10 nm. Small Craft Advisory until 9 AM PDT this morning for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...JM LONG TERM....JM AVIATION...Sarment MARINE...Sarment 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