Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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674 FXUS66 KMTR 080451 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 951 PM PDT Tue May 7 2024 ...New UPDATE... .SYNOPSIS... Issued at 116 PM PDT Tue May 7 2024 A warming trend begins Wednesday as offshore winds develop, with a Wind Advisory for the interior North Bay on Wednesday morning. Warmest temperatures are expected Thursday and Friday before a slight cooldown into the early part of next week. && .UPDATE... Issued at 946 PM PDT Tue May 7 2024 The short term forecast remains on track. There is some consideration to broadly reduce the high temperatures on Thursday and just keep the favorable hot spots where they are. Areas such as the San Lorenzo Valley may stay the same, but our forecast is above all GFS and ECMWF ensemble members in several areas of the North and East Bay. These temperatures will be massaged on the night shift. The wind forecast is holding on to marginal wind advisory thresholds and the advisory remains in effect. && .SHORT TERM... (This evening through Wednesday) Issued at 116 PM PDT Tue May 7 2024 Clear skies throughout the day today with little to no stratus development this evening and overnight. High temperatures today range from the mid 50s to low 60s on the coast, the upper 60s to lower 70s on the Bayshore, and into the mid to upper 70s in the interior valleys. Breezy northwest winds will develop this afternoon, gusting up to 20 to 25 miles per hour in the ridgelines and passes. Overnight lows will generally range from the mid 40s to the lower 50s, with some of the most interior regions seeing lows in the lower 40s. A warming trend begins Wednesday, with a ridge building over the northeast Pacific expanding into the Pacific Northwest, interacting with a piece of an upper level low over the Northern Plains that regresses over the Rocky Mountains and breaks off into a weak cut- off low over the Great Basin. The end result is that offshore flow will start to develop through Wednesday, with the higher elevations and North Bay being the first to experience the wind shift. A Wind Advisory is now in effect for the North Bay interior mountains and valleys from 1 AM to 11 AM on Wednesday, for sustained winds of 20 to 30 miles per hour and gusts up to 45 miles per hour in the higher elevations. The rest of the region should see wind gusts topping out around 20 to 25 miles per hour. High temperatures on Wednesday range from the low to mid 60s along the coast to the upper 70s to lower 80s in the interior valleys. Despite the breezy offshore winds and the warming trend, very little fire danger is expected, with moist fuels mitigating fire weather concerns throughout the region. && .LONG TERM... (Wednesday night through next Monday) Issued at 116 PM PDT Tue May 7 2024 The warming trend continues into the early part of the weekend, with Thursday and Friday expected to be the warmest days of the event. High temperatures range from the upper 60s to lower 70s near the coast, to the upper 80s to lower 90s inland. With northeasterly offshore flow continuing through Thursday, and with prior pattern recognition of warmer temperatures in downslope areas as a result, have increased temperatures on Thursday from the previous forecast. The seasonably warm temperatures are causing a minor to moderate HeatRisk, meaning that a low to moderate risk for heat related illnesses exists for vulnerable populations (children, the elderly, pregnant women, or those without adequate shelter or cooling), with moderate HeatRisk values concentrated in the interior regions of the North, East, and South Bays. For some context: downtown San Francisco, which sees highs around the mid 60s this time of year, is expected to top out at 81; Santa Rosa, where the seasonal average high is in the mid 70s, is facing a high temperature of 89; and Salinas is forecast to reach a high of 80 versus a seasonal average high of 68. With the significant warm up expected for the rest of the week, here`s a reminder of some heat safety tips: * Stay hydrated and drink plenty of fluids. * Wear lightweight, light-colored clothing. * Reduce time spent outdoors or stay in the shade. * Never leave people or pets unattended in vehicles. * Use sunscreen if going to the coast or the pool. The heat should start to abate on Sunday as onshore flow returns to the region, but temperatures warmer than the seasonal averages are expected to continue for the foreseeable future, with CPC products stating that temperatures above seasonal averages continue into the third week of May. && .AVIATION... (00Z TAFS) Issued at 438 PM PDT Tue May 7 2024 VFR through the TAF period. Winds diminish overnight and increase again to become breezy Wednesday morning. Most terminals can expect N/NW winds 10-15 kts with gusts 20-25 kts during the late morning to afternoon, and diminishing once again Wednesday night. High confidence in CLR skies across most of the area tonight, with the exception of FEW stratus along the Monterey Bay and Central Coast. Vicinity of SFO...VFR through the period. Gusty N/NW winds Wednesday afternoon to 20 kts and high confidence in CLR skies through the period. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Medium-high confidence in VFR through the period. A few locations along the immediate coast have a low chance of see some brief FG overnight into Wednesday morning. Otherwise, high confidence in CLR skies from sunrise onward. && .MARINE... (Today through Sunday) Issued at 1053 AM PDT Tue May 7 2024 Strong northerly winds continue through the midweek, with gale- force gusts expected over the outer waters and near the Big Sur coast. Towards the early Thursday morning, winds slowly ease to become fresh to moderate. However, as a result of strong winds in the early portion of the week, significant wave heights will build to heights of 15 to 16 feet over the outer waters by mid- week. Sea conditions will be hazardous Tuesday and Wednesday with gale warnings issued for portions of the coastal waters. By the late week into the weekend, winds ease to become gentle, significant wave heights gradually diminish to 5 to 7 feet, and dry weather continues as high pressure dominates. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory from 1 AM to 11 AM PDT Wednesday for CAZ504-506. PZ...Small Craft Advisory from 9 AM to 3 PM PDT Wednesday for SF Bay N of Bay Bridge. Small Craft Advisory 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 Wednesday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm. Gale Warning until 3 PM PDT Wednesday for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...DialH LONG TERM....DialH AVIATION...Behringer 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