Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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729 FXUS66 KMTR 302330 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 430 PM PDT Thu May 30 2024 ...New AVIATION... .SYNOPSIS... Issued at 220 PM PDT Thu May 30 2024 Weak ridging will bring a minor warming trend to the region through Friday. A trough will move into the Pacific Northwest this weekend though, which will help strengthen the onshore flow and deepen the marine layer, bringing a slight reprieve to the warmer conditions. However, high pressure will build back across the region by the middle of next week, bringing a much more pronounced warming trend to the region, especially across the inland areas. Inland areas could be upwards of 10 to 20 degrees above normal, with a moderate heat risk by Wednesday. && .SHORT TERM... (This evening through Friday) Issued at 220 PM PDT Thu May 30 2024 Water vapor imagery continues to show relatively zonal upper level flow across California this afternoon, with a few high clouds still moving across the far northern portion of the state. Meanwhile, patchy low clouds continue to linger along the Big Sur Coast and the Monterey Peninsula. Given the sunny skies this afternoon, temperatures are running similar or up to 5 degrees warmer than this time yesterday. This will make for pleasant afternoon and evening across the region. The low clouds will likely move back into the Monterey Bay tonight, with a clouds start to the day expected on Friday. Otherwise, the minor warming trend that we saw today will continue into the day on Friday, with most areas similar to or slightly warmer than where they peaked today. && .LONG TERM... (Friday night through next Wednesday) Issued at 220 PM PDT Thu May 30 2024 Things will begin to change on Friday night though as a series of systems take aim at the Pacific Northwest. As a result, this will bring the return of the marine layer to most areas as well as stronger onshore flow. Therefore, expect a cooling trend to develop, with inland temperatures seeing the greatest decrease. Low clouds may be hard to clear the coast each afternoon, with unseasonably cool conditions prevailing along the immediate coast. In fact, cannot rule out some late night or early morning drizzle each day this weekend. A more potent system will take aim at the Pacific Northwest and far Northern California on Sunday into Monday. While we are still not expecting any rain from this system this far south, expect quite a bit more cloud cover to spread across the region late Sunday and into Monday as well as some coastal drizzle. The primary concern for this forecast though is with the warming trend associated with the high pressure building over the West starting on Tuesday. While Tuesday will be warmer, expect significant warming to occur for Wednesday and Thursday as the ridge axis builds over the Four Corners and potentially even more westward than that. These days could be the hottest we have seen this year for our inland areas, with inland regions flirting with or even surging above 100 degrees. In fact, the probabilistic guidance is suggesting a 75% chance of inland areas reaching 95 degrees and a 40% chance of inland areas topping 100. Therefore, there is high confidence that the inland areas will be quite hot, ranging between 8 to 15 degrees warmer than normal and potentially upwards of 10 to 20 degrees above normal. CPC is even highlighting the potential for excessive heat in the Central Valley, especially for June 5th to 7th. While we may get some influence of the marine layer, believe that it will be quite shall, with inland areas seeing the greatest warm up and potential for significant heat and a moderate heat risk. As previously stated, the marine layer influence will be the biggest question for the coastal areas, with ensemble spreads for the coastal areas are upwards of 20 degrees. This high uncertainty really has to do with the placement of the ridge axis, and whether or not we can get some light offshore winds developing. Until the placement of the ridge axis becomes more clear, the uncertainty will remain high for the coastal areas. Therefore, we will continue to watch how this event develops over the next several days. CPC`s 8 to 14 day outlook also shows a better chance of above normal temperatures as well, so there is a chance that this heat turns into a minor heatwave, extending through the remainder of the work week. Palmer && .AVIATION... (00Z TAFS) Issued at 413 PM PDT Thu May 30 2024 Another round of breezy to gusty winds this afternoon, with stronger winds just offshore. Winds will ease somewhat later this evening and overnight. Clear skies by late morning through the afternoon on Friday, with winds increasing out of the west once again in the afternoon. Vicinity of SFO...Breezy to gusty winds this afternoon will ease later this evening but may remain breezy at times through the overnight. Mostly clear skies on Friday will keep VFR in place through the forecast period with more breezy winds in the afternoon. SFO Bridge Approach...Similar to SFO Monterey Bay Terminals...VFR will prevail through the evening and most of the overnight with IFR/LIFR stratus ceilings developing early tomorrow morning before eroding by mid-morning, becoming VFR for the remainder of the forecast period. && .MARINE... Issued at 841 AM PDT Thu May 30 2024 Breezy to gusty winds last in the outer waters into the weekend with gale force winds expected to return into Saturday morning. Significant wave heights offshore build to 12 feet tonight with but abating into Friday and through the weekend. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 3 AM PDT Friday for Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory from 3 PM Friday to 3 AM PDT Saturday for Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 3 PM PDT Friday for Pt Arena to Pt Reyes 10-60 NM. Gale Warning from 3 PM Friday to 3 AM PDT Saturday for Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory until 3 AM PDT Saturday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...Palmer LONG TERM....Behringer AVIATION...JM MARINE...Murdock 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