Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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444 FXUS66 KMTR 090606 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1106 PM PDT Wed May 8 2024 ...New AVIATION... .SYNOPSIS... Issued at 1241 PM PDT Wed May 8 2024 Warming trend begins today with the warmest temperatures expected Thursday and Friday. Offshore winds continue through Thursday with a Wind Advisory in effect for the North Bay interior mountains through Thursday morning. A slight cooldown will begin this weekend and continue into the early part of next week. && .UPDATE... Issued at 936 PM PDT Wed May 8 2024 The wind advisory remains in effect for the interior North Bay mountains. While winds have come down in the valleys, a couple PGE stations in the Mayacamas are reporting wind gusts above 50 mph. Otherwise the forecast remains on track with dry and warm conditions expected tomorrow. The temperatures have actually been pretty slow to come down this evening, which may influence the high temps tomorrow as the high resolution guidance adjusts before the overnight forecast is issued. && .SHORT TERM... (This evening through Thursday) Issued at 1241 PM PDT Wed May 8 2024 Summary: * Warming trend begins today and peaks Thursday and Friday * Minor HeatRisk throughout the region, Moderate HeatRisk in the interior Bay Area * Breezy northerly winds continue today * Wind Advisory for the North Bay interior mountains through 8 AM Thursday * Gradual cooldown begins this weekend through early next week The warmup has begun as temperatures across the region are generally running around 5 to 10 degrees above the same time yesterday. A ridge is building over the eastern North Pacific, building into British Columbia and the Pacific Northwest through the next couple of days. At the same time, an upper level low centered over the northern Plains is elongating along a generally east-west axis, the trough regressing into the Great Basin and breaking off into a weak cut-off low. The combination of these two systems is leading to north to northeast flow aloft, a situation that generally leads to warmer temperatures in the area. Forecast highs are generally reflecting today`s warming trend, with interior locations seeing highs into the lower 80s, the Bayshore seeing highs in the upper 70s, and mid to upper 60s expected along the coast. Breezy north winds continue to develop with wind gusts up to 20-25 miles per hour across the valley regions. The higher elevations, especially in the North Bay, are in a lull through the afternoon, but gusts up to 45 to 55 miles per hour are expected to resume later this evening and continue through Thursday morning. Thus, the Wind Advisory for the North Bay interior mountains continues through 8 AM on Thursday. Overnight lows will be quite warm across the Bay Area, with temperatures on Thursday morning in the mid to upper 50s. The Central coast will see somewhat cooler lows overnight in the upper 40s to low 50s. The heat event starts to peak on Thursday, with interior highs in the mid to upper 80s and coastal highs in the low to mid 70s. Of note, downtown San Francisco is currently expected to reach 81 on Thursdsay; if the forecast verifies, it would be the first 80-degree day in the city since last October. Winds are expected to diminish through the day Thursday. This section from yesterday continues to apply today: 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. 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. && .LONG TERM... (Thursday night through next Tuesday) Issued at 1241 PM PDT Wed May 8 2024 Friday will be the second day of the peak heat event, and while areas closer to the coast might see temperatures drop by a few degrees, the interior areas should expect temperatures to rise even further, as high as the lower 90s in the warmest locations. Cooling begins Saturday, as a decaying ridge allows onshore flow to reassert itself. Coastal regions will see the most cooling, and by Sunday, should return to seasonal temperatures for this time of year (generally, the low to mid 60s). At the same time, the interior will continue to see highs in the low to mid 80s, warmer than the seasonal average, through the early part of next week. Ensemble models and clusters are showing that another ridge approaches the West Coast next week, which could help maintain temperatures above the seasonal averages. CPC products are showing temperatures above seasonal averages continuing into the third week of May. && .AVIATION... (06Z TAFS) Issued at 1106 PM PDT Wed May 8 2024 VFR through the TAF period, though stratus will begin to hug the central coast in the early morning of Thursday as it begins to travel northwards along the coast of California. At this time, not expecting any intrusions of stratus over area terminals within the current TAF period. Winds will remain elevated somewhat throughout the night tonight for most terminals remaining above 7 knots. Winds slowly turn throughout the morning and afternoon of Thursday to go from NE to a more N/NW flow and increase to become breezy. By the late evening of Thursday, winds will ease to become light. Vicinity of SFO...VFR. Surface winds expected to ease to become light tonight, though winds aloft will remain somewhat elevated, so have included LLWS in the TAF to reflect this. In the afternoon of Thursday, breezy N/NW winds return, but ease to become light and variable into the late night. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR through the TAF period, though a southerly surge of stratus will slowly creep its way up the coast, hinting at the development of CIGs just beyond the current TAF period. Otherwise, light winds overnight tonight and early Thursday morning, though KSNS will see breezy southerly drainage winds in the early morning. Come the afternoon, breezy onshore winds return. && .MARINE... (Today through Monday) Issued at 908 AM PDT Wed May 8 2024 High pressure to the north and low pressure to the south will maintain moderate to locally strong northerly winds over the coastal waters and bays through tonight. The stronger northerly winds will result if fresh steep swell today. By Friday, winds are largely light to moderate across much of the waters. Wave heights gradually diminish to around 5 to 7 feet by late week. Dry weather continues through the forecast period as high pressure dominates. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory until 8 AM PDT Thursday for CAZ504. PZ...Small Craft Advisory until 3 AM PDT Thursday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...DialH LONG TERM....DialH AVIATION...AC MARINE...MM 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