Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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273 FXUS66 KMTR 181811 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1111 AM PDT Sat May 18 2024 ...New AVIATION... .SYNOPSIS... Issued at 300 AM PDT Sat May 18 2024 Quiet weather persists. Stratus coverage expected to dissipate by mid-to-late morning with clearer, sunnier conditions expected during the afternoon. Temperatures cool down slightly Saturday before a weak warming trend begins Sunday. For coastal areas, stratus will return during the evening hours but shouldn`t extend too far inland. && .UPDATE... Issued at 854 AM PDT Sat May 18 2024 Low clouds spread well inland into the region`s valleys overnight and persist this morning. They even made it into the North Bay! These low clouds will retreat to the coast by late morning or early afternoon. However, many coastal locations will remain in the clouds throughout a good portion of the day and may only see the sun for brief periods of time. That said, have lowered forecasted high temperatures by a few degrees for the day as a weak, dry frontal boundary moves across the region. && .SHORT TERM... (Today and tonight) Issued at 300 AM PDT Sat May 18 2024 Stratus coverage is increasing over the Central Coast, North Bay, and portions of the rest of the Bay Area. Inland stratus coverage is a little patchier tonight than last night with the lowest clouds staying closer to the coast. Friday`s high temperatures were limited in areas where widespread stratus lingered through the late morning hours and prevented increased surface warming from occurring. In the case of Monterey, airport observations showed unbroken stratus coverage throughout the entirety of Friday with the recorded high 6 degrees cooler than average. A similar scenario may occur along the coast again today and help keep coastal temperatures slightly cooler than originally forecast. Stratus coverage is expected to dissipate for along the coast and inland by mid to late morning with sunny skies returning during the afternoon. Chances for coastal drizzle are lower than yesterday but cannot rule out the possibility of a trace to a few hundredths of an inch accumulating. An additional influence on today`s high temperatures is a weak surface cold front that will move through the Bay Area today. This will bring slightly cooler (3-4 degrees) temperatures inland where stratus coverage is less widespread and has a less dominant influence. Precipitation is not expected to occur with this system. Despite temperatures being slightly cooler, highs should still be in the mid to upper 70`s inland and upper 50`s to low 60`s along the coast. All together, should be a pleasant day with seasonally warm temperatures and sunny skies in the afternoon. Take some time to get outside today and enjoy it! && .LONG TERM... (Sunday through Friday) Issued at 300 AM PDT Sat May 18 2024 Upper level zonal flow will gradually deepen as a longwave upper level trough moves into the Western United States over the weekend. A weak warming trend will take place Sunday through the middle of the work week with inland highs in the mid 70`s to low 80`s. Minor heat risk is expected for individuals who are extremely sensitive to heat Monday and Tuesday. Ensemble consensus largely shows inland highs in the mid 70`s to low 80`s through mid-week with higher end scenarios showing highs up to 85-87 degrees. Tuesday looks to be the warmest day with probabilistic guidance showing a 50-60% chance of portions of the North Bay and South Bay breaching the low to mid 80`s. Highs become more uncertain Thursday and Friday with ensembles agreeing that temperatures will cool down but they did not reach an agreement as to how significant this cool down will be. Upper level troughing looks to persist through the week with shortwave ridging building Friday into next weekend. Persistence is key for this stratus forecast wherein stratus will continue to develop along the coast overnight, clear out by mid to late morning, and return during the early evening hours. A deeper marine layer is expected to persist which will help keep stratus more confined to coastal areas and not move as far inland. && .AVIATION... (18Z TAFS) Issued at 1111 AM PDT Sat May 18 2024 Stratus this morning is bringing IFR/MVFR conditions to many terminals. However, as stratus continues to recede and clearing begins later this morning, expect VFR conditions to return for most terminals. Winds to be onshore and breezy to moderate, reaching to around 12-15 knots for most terminals this afternoon. Winds weaken into the late night to become light, and stratus returns to a select few coastal terminals (predominantly Monterey Bay) bringing MVFR/IFR conditions. Terminals further inland are not expected to see much in the way of impacts from stratus. However, the North Bay is likely to see fog development in the early morning of Sunday, leading to IFR/LIFR conditions. Vicinity of SFO...VFR conditions return late this morning as stratus recedes. Winds increase out of the west this afternoon to around 13 knots. At this time, low confidence in CIGs returning this evening as a result of stratus. Highest confidence is in the development of FEW-SCT low clouds filtering in through the Golden Gate and San Bruno gaps, but maintaining VFR conditions through the overnight. Winds light overnight, increasing Sunday afternoon to become breezy once more. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...MVFR conditions linger into the early afternoon today until stratus clears briefly to allow for VFR conditions. VFR is likely to last only a few hours with a few low clouds continuing to dot the sky despite clearing. Winds breezy and onshore around 15 knots. Stratus pushes inland to bring a return of MVFR CIGs in the early evening. Through the overnight, CIGs are expected to lower to become IFR. && .MARINE... (Today through Thursday) Issued at 854 AM PDT Sat May 18 2024 Winds out of the north strengthen to become strong and slowly spread over the outer waters through the weekend. These stronger winds are expected to last through most of the upcoming work week. Gale force gusts build in the far northern waters today and are expected to last through at least Monday. Expect hazardous conditions and steeper wind waves from these building winds. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 3 PM this afternoon to 3 AM PDT Sunday for Pt Arena to Pt Reyes 0-10 nm. Gale Warning from 3 AM Sunday to 3 AM PDT Monday for Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory from 9 AM Sunday to 3 AM PDT Monday for Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory from 3 PM Sunday to 3 AM PDT Monday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm. Gale Warning until 3 AM PDT Monday for Pt Arena to Pt Reyes 10- 60 NM. Small Craft Advisory from 9 PM this evening to 3 AM PDT Monday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...Kennedy LONG TERM....Kennedy AVIATION...AC MARINE...AC 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