Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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870 FXUS66 KMTR 180551 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1051 PM PDT Mon Jun 17 2024 ...New AVIATION... .SYNOPSIS... Issued at 153 PM PDT Mon Jun 17 2024 Dry and breezy conditions continue into Monday night. Better onshore flow and moisture return by midweek. Another warming trend on the way for the upcoming weekend. && .UPDATE... Issued at 836 PM PDT Mon Jun 17 2024 The Red Flag Warning that was in effect for the North Bay Interior Mountains was allowed to expire at 8 PM this evening as relative humidity values over the region increase to 35-45 percent overnight and wind speeds reduce. However, while some moistening will occur tomorrow, there remains an elevated fire weather threat through Tuesday away from the immediate coastline/bayshore as breezy onshore flow persists. Smoke from the Sites Fire Colusa County is moving over the North Bay and part of the Bay Area this evening as transport winds over that region are out of the northeast. The ongoing forecast remains on track with no updates anticipated at this time. && .SHORT TERM... (This evening through Tuesday) Issued at 153 PM PDT Mon Jun 17 2024 Gusty northwest winds continue to mix down toward the surface this afternoon, as high as 30 mph in some of our higher locations over the interior coastal ranges and passes. The gusty winds combined with a dry air mass producing min RH values as low as 10 percent will persist for the remainder of this afternoon into the evening hours. A Red Flag Warning remains in effect until 8pm for the North Bay Interior Mountains in Napa county. A positively tilted upper level trough will keep winds elevated with respect to the normal diurnal trend overnight into Tuesday. Embedded weak shortwave ridging will help to ease surface winds Tuesday, especially inland away from the coast, however the Salinas Valley will reamin breezy as onshore northwest surface flow channels inland. Temperatures will remain near seasonal averages through midweek. && .LONG TERM... (Tuesday night through next Sunday) Issued at 145 PM PDT Mon Jun 17 2024 A warm up continues to highlight the extended forecast. Persistent upper level troughing over our region begins to shift east and flatten late Thursday into early Friday, continuing into the weekend. A weak ridge begins to build with the ridge axis just to our east over the Sierra Mountains Friday afternoon. An increase in heights and thickness will allow another round of heat to build, especially the farther you move inland from coastal areas. Elevated areas of southern Monterey and San Benito county may see triple digit heat, along with portions of Contra Costa and Alameda county to the north on Saturday, which should be the peak of this round of heat. && .AVIATION... (06Z TAFS) Issued at 1034 PM PDT Mon Jun 17 2024 VFR through the TAF period. Winds weaken into the late night becoming light. Winds stay light into the late morning before moderate to breezy winds arrive into Tuesday afternoon. Smoke from fires to the north could cause some haze and smoke to filter into the North Bay and around the SF Bay, but visibilities don`t look to be greatly affected. Winds will reduce into Tuesday evening. Vicinity of SFO...VFR through the TAF period. Winds reduce into the night becoming light to moderate. Another round of breezy to gusty winds starts building in the early afternoon with peak gusts expected to be around 28 kts. These stronger gusts last into the night. Gusts stop but moderate winds last into late Tuesday night. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR through the TAF period. Light to moderate winds last through the late morning before more moderate westerly winds arrive. Winds at the terminals reduce into Tuesday night. && .MARINE... (Tonight through next Sunday) Issued at 836 PM PDT Mon Jun 17 2024 Widespread strong northerly/northwesterly breezes with near gale- force gusts will persist through Wednesday. Gusty winds will diminish overall beginning Thursday with strong breezes remaining exclusive to the outer waters through the weekend. Significant wave heights will build to 9-11 feet today, abate through Friday, and build back up to 10-12 feet towards the end of the the weekend. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 3 PM to 9 PM PDT Tuesday for SF Bay N of Bay Bridge. Small Craft Advisory from 9 AM Tuesday to 3 AM PDT Wednesday for Mry Bay. Small Craft Advisory until 3 AM 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 Reyes to Pigeon Pt 0-10 nm. Gale Warning from 3 PM Tuesday to 3 AM PDT Wednesday for Pt Pinos to Pt Piedras Blancas 0-10 nm. Gale Warning until 3 AM PDT Tuesday for Pt Arena to Pt Reyes 10- 60 NM. && $$ SHORT TERM...JM LONG TERM....JM AVIATION...Murdock MARINE...SO 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