Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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717 FXUS66 KMTR 282226 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 326 PM PDT Fri Jun 28 2024 ...New FIRE WEATHER... .SYNOPSIS... Issued at 251 AM PDT Fri Jun 28 2024 A well established marine layer and onshore flow will keep temperatures cool near the coast while inland areas warm to into the 90`s throughout the weekend. Pattern change causes a warm up early next week, with monitoring potential excessive heat for the second half of next week. && .SHORT TERM... (This evening through Saturday) Issued at 313 PM PDT Fri Jun 28 2024 Low clouds persist along the Monterey coastline with stratus expected to return inland overnight along the Central Coast and up the coast of the SF peninsula. Widespread minor heat risk and patches of moderate heat risk over the North and East Bay continue through Saturday. Overnight temperatures Friday into Saturday will largely be in the mid 50s to low 60s. A slight warming trend is expected to kick off Saturday and Sunday before the more substantial warming anticipated next week. High temperatures on Saturday will warm slightly (2 to 4 degrees on average) with inland highs largely in the 80s to low 90s. Favored hotspots in the North and East Bay may reach the mid 90s. Closer to the coast, cooler temperatures prevail with highs in the low to mid 60s. Given the long term trend for warmer, excessively dangerous heat next week - make the most out of these comparatively cooler temperatures and take care of any outdoors activities you may need to do this weekend. && .LONG TERM... (Saturday night through next Thursday) Issued at 313 PM PDT Fri Jun 28 2024 A weak warming trend continues through Sunday with temperatures similar to Saturday in the 80s to low 90s expected. The main story for our long term forecast: a strengthening surface high pressure system and a large upper level ridge will move inland and bring dangerously hot, well above average temperatures for all areas away from the coastline in the Bay Area and Central Coast. This will be a prolonged heat event beginning Monday and continuing through the end of the week with widespread major to extreme heat risk expected over the majority of the Bay Area and Central Coast. An Excessive Heat Watch has been issued beginning Tuesday morning (when widespread major to extreme heat develops) through Friday evening. Wondering what an Excessive Heat Watch is? An Excessive Heat Watch is issued when dangerous heat is possible in the coming few days. An Excessive Heat Warning is when dangerous heat is currently occurring or about to start occurring. For now, we are still in the watch phase but everyone should start preparing for the excessive heat next week by rescheduling any outdoors activities and having a way to access somewhere that has A/C (for more ways to prepare see Heat Safety and Impacts section below). Getting into the gritty details of what we know so far: High temperatures will warm into the upper 80s to upper 90s beginning Monday with moderate heat risk expected over much of the Bay Area and Central Coast. Tuesday will mark the beginning of widespread excessive, dangerous heat with high temperatures breaching the mid 90s to low 100s. Across favored hot spots in the North/East Bay and portions of interior Monterey and San Benito Counties high temperatures may reach up to 110 degrees with extreme heat risk forecast for these areas. Overnight temperatures are not spared from this warming trend with widespread overnight lows in the upper 50s to mid 60s. In areas where extreme heat risk is expected, overnight low temperatures will be in the upper 60s to in the 70s. Longer term guidance (beyond this forecast period) suggests that anomalously warm temperatures may persist past Friday into next weekend. We will continue to monitor this as we get closer to the event. Daytime relative humidity values will drop beginning Tuesday through the end of the week with widespread daytime RH values in the mid teens to mid twenties across the interior. For most areas there will be fair to good overnight relative humidity recoveries (60-70%) while portions of interior North/South/East Bay and interior Monterey/San Benito county may see locally poorer overnight relative humidity recoveries (20-40%). This will bring elevated fire weather concerns across interior portions of the North/East/South Bay with emphasis placed on the interior North Bay Mountains and far interior East Bay Hills. Remember, we have had several fires already this fire season so fine fuels (grass, shrubs, etc.) are already dry and ready to burn. Given that Fourth of July takes place in the middle of this heat wave take GREAT care with any outdoor activities involving barbecues, sparks, or any sort of flame. One last thing to note - we are entering the King Tide cycle beginning this week with minor coastal flooding possible in Bayside portions of the North Bay and along the Embarcadero in San Francisco. && .AVIATION... (18Z TAFS) Issued at 1011 AM PDT Fri Jun 28 2024 Widespread VFR returns into the afternoon and lasts into the night. Winds increase into the afternoon with gusty winds expected at SFO and along the coast, while other areas stay moderate to breezy. Winds reduce into the night as IFR/MVFR CIGs move over the coast and Monterey Bay terminals. These CIGS look to last into late Saturday morning as widespread moderate to breezy winds build. Vicinity of SFO...VFR through the TAF period. Expect breezy wot gusty winds this afternoon with gusts peaking around 24 kts. These winds last into the evening, reducing, but staying breezy into the late night. Breezes reduce into early Saturday, but pick up again that afternoon. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Lingering clouds at MRY erode into the afternoon with VFR expected afterward through the early night. Moderate to breezy westerly winds build this afternoon, with slightly stronger winds expected at the immediate coast. Winds reduce the early night as IFR CIGS move inland and fill over MRY, with SNS filling later into the night. && .MARINE... (Today through Wednesday) Issued at 1011 AM PDT Fri Jun 28 2024 Breezy to gusty northwest winds continue into the next work week before reducing to more moderate winds. Significant wave heights begin to build to 10-12 feet towards the beginning of the next work week. Light southerly swell continues to move through the waters alongside moderate northwesterly swell. && .FIRE WEATHER... Issued at 322 PM PDT Fri Jun 28 2024 Temperatures will hover right around seasonal averages through the weekend with relatively light onshore breezes. There is an Excessive Heat Watch in effect across our area for Tuesday through Friday of next week, encompassing the Fourth of July holiday. Confidence is increasing for an unusually strong dome of high pressure across our region that will produce daily maximum temperatures well above normal and subsequently, very low min RH values. The building heat will also result in poor overnight RH recovery. Please plan accordingly. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Excessive Heat Watch from Tuesday morning through Friday evening for CAZ502>504-506-508-510-512>518-528. PZ...Small Craft Advisory until 3 AM PDT Saturday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory from 9 AM Saturday to 9 AM PDT Sunday for Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory from 3 PM Saturday to 9 AM PDT Sunday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 9 AM PDT Sunday for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...RGass LONG TERM....Canepa AVIATION...Kennedy 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