Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

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000 FXUS66 KMTR 021735 AFDMTR Area Forecast Discussion National Weather Service San Francisco Bay Area 935 AM PST Tue Mar 2 2021 .SYNOPSIS...Dry and mild weather conditions continue with slight cooling late in the week. Rain chances increase late Friday into Saturday with the potential for unsettled conditions to persist into early next week. && .DISCUSSION...as of 09:30 AM PST Tuesday...A chilly start for some of our interior valleys as early morning temperatures dipped into the mid 30s with a few spots in the low 30s. Luckily, morning sunshine has warmed up many of those colder areas and most of our current temps are in the upper 40s to mid 50s. Forecast is still on track so no updates this morning. Will be concentrating on the system that is forecast to move into northern and central CA Friday evening through Saturday and adjust the forecast as needed with respect to rain and winds. && .PREV DISCUSSION...as of 03:23 AM PST Tuesday...A mid/upper level low pressure system and associated trough remains well off of the West Coast early this morning. It`s only impact to the region is mid/high level clouds advecting inland across California as dry weather conditions prevail at the surface. This system is forecast to remain well enough offshore to maintain dry conditions over the region before eventually dropping southward and then across southern California on Wednesday. Day-to-day fluctuations in temperatures are expected to be minimal through midweek, yet will be at or above seasonal averages. Generally speaking, look for upper 50s to lower 60s at the coast with more widespread 60s to near 70 inland. Meanwhile, overnight lows will range from the mid/upper 30s in the colder interior valleys with 40s elsewhere. As the aforementioned system shifts inland over the Desert Southwest through midweek, a mid/upper level trough will deepen over the eastern Pacific late in the week. This system is then forecast to shift eastward toward the West Coast late in the week potentially bringing widespread precipitation to the region Friday night into Saturday. However, the deterministic and most ensemble members only indicate light precipitation for our region. Temperatures late in the week and into the upcoming weekend will also cool as a result. Beyond the upcoming weekend, the ensembles favor unsettled weather conditions across our region heading into next week as troughing persists over the eastern Pacific and along the West Coast. However, this pattern would likely only result in light precipitation amounts for our region. Seasonably cool conditions are also likely given this pattern. && .AVIATION...
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as of 9:35 AM PST Tuesday...For the 18Z TAFs. VFR conditions through the period. Satellite imagery shows some high clouds over land and low clouds still well offshore over the ocean. Still do not expect these clouds to impact the terminals, though FEW-SCT cigs may reach some of the coastal taf sites. Latest high res models have backed off on low level moisture overnight, therefore have not added in BKN low cigs into the 18z taf package. Expect increasing high clouds from the upper low offshore as it continues to move towards southern California. Generally light winds at or under 10 kt, onshore this afternoon. Vicinity of KSFO...VFR, light and variable wind increasing to 10 knots W/NW in the afternoon and early evening. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...VFR, continued SE winds this morning around 5 to 10 kt should turn onshore this afternoon and evening. Latest models have backed off on low level moisture along the coast and over the Monterey Bay tonight/tomorrow morning. Elected to keep BKN low cigs out of the tafs for now, but some SCT low clouds still possible overnight.
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&& .MARINE...as of 08:57 AM PST Tuesday...A low pressure system over the eastern Pacific will move across the waters into tomorrow, though winds will remain generally light to locally moderate. Building northwest swell will cause hazardous seas conditions for smaller vessels later today into the evening. Winds will gradually increase and turn southerly on Thursday ahead of the next frontal system set to arrive Friday and Saturday. Moderate northwest swell will over the next couple of days before a longer period northwest swell arrives late this week. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tday...SCA...Pt Arena to Pigeon Pt 10-60 nm from 12 PM SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm from 4 PM && $$ PUBLIC FORECAST: RGass AVIATION: AS MARINE: AS 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

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