Point Arena to Pigeon Point between 60 and 150 NM Offshore Forecast
FORECAST FOR PZZ825 CURRENTLY UNAVAILABLE
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Area Forecast Discussion National Weather Service San Francisco CA 1047pm PDT Sat Oct 12 2024 Issued at 905pm PDT Sat Oct 12 2024 Forecast remains on track, with rainfall across Sonoma and Napa County expected to taper off by midnight. Thus far the highest total measured is just south of Occidental with 0.60", and some elevated locations farther inland receiving up to 0.40". The next few days will be slightly warmer, before the next upper low brings chances for more widespread rainfall by Wednesday. The Blue Angels are expected to try and fly around 3PM PDT tomorrow, which is the best window of time in our current forecast, though certainly not a guaranty with patchy fog and low stratus expected to be lingering in the vicinity. .SHORT TERM... (This evening through Sunday) Issued at 201pm PDT Sat Oct 12 2024 Scattered light rain showers continue across the North Bay and portions of the SF Peninsula through the remainder of today as a weak cold front passes through. The highest totals so far have been in the coastal North Bay Mountains with Sea Ranch reporting 0.43" and the Hawkeye Raws site reporting 0.32" in the last 12 hours. Precipitation totals are lower in southern Sonoma and northern Marin county with totals ranging from a few hundredths of an inch to a little over a tenth of an inch. The bulk of the rain has passed but sites within the interior North Bay may see a few hundredths of an inch this afternoon while coastal Sonoma county may see an additional 0.10" this afternoon. As the cold front departs, the marine layer will remain fairly deep with widespread low level clouds expected overnight into tomorrow morning. Overnight low temperatures will largely be in the 50's to low 60's across the board. High temperatures tomorrow return to seasonal to slightly below average for most sites. Inland highs will largely be in the mid to upper 70s with the hottest locations in interior North Bay, East Bay, and southern Monterey County reaching the low 80s. Temperatures remain much cooler directly along the coast with highs largely staying in the low to mid 60s while highs slightly inland from the coast will reach the upper 60s to low 70s. While rain chances diminish by this evening, drizzly conditions remain a possibility tonight into tomorrow morning due to increased atmospheric moisture and widespread low level clouds. For those enjoying fleet week, conditions should improve by late morning but be prepared for some light drizzle if you are out and about in the early morning hours. Long Term (Sunday night through next Friday) Issued at 201pm PDT Sat Oct 12 2024 The synoptic pattern this week will be fairly progressive and gives us a variety of things to talk about. Starting with the early work week, shortwave ridging will develop Sunday and persist through Tuesday. This results in a slight warming trend (1-2 degrees) Monday and Tuesday with inland highs mainly in the mid to upper 70s while the hottest inland areas may see the low 80s. Coastal temperatures will remain on the cooler side in the 60s while locations slightly inland from the coast will reach the low 70s. Beginning late Tuesday into early Wednesday, another upper level low will start to move inland and bring with it widespread potential for light rain across the Bay Area and Central Coast. High temperatures will cool down slightly into the upper 60s to mid 70s across the interior and into the 60s along the coast Wednesday and Thursday. By late week, high temperatures start to build again into the upper 70s to low 80s across the interior as upper level ridging returns moves inland late next weekend. For the second low pressure system there are two main uncertainties we need to address: forecast precipitation totals and the strength/progression of the low pressure system. First, our current forecast shows most sites will stay less than 0.10" everywhere except the Santa Cruz Mountains and across the North Bay where a few tenths of an inch (0.1-0.3") are possible. Ensemble guidance primarily agrees with this range, but, the GFS (Global Forecast System) ensemble continues to show a few outliers that are consistently pushing for much higher totals (up to an inch of rain in the wettest locations). These totals are considered outliers given that the European ensemble and the majority of the GFS ensemble members are in agreement with our current forecast. However, given that this event is still a few days out we will continue to monitor and adjust our forecast totals as it grows closer. The second uncertainty has to do with how much this upper level low will strengthen and what will happen as it progresses eastward. The European and GFS deterministic model both show fairly similar initial progressions of the upper level low as it moves inland. However, by Friday, the GFS shows the low strengthening/deepening and, eventually, becoming a cut off low over the four corners region. In this scenario, dry conditions and gusty offshore winds (near gale force wind gusts over the marine environment and between 25 to 35 mph wind gusts across mountain gaps/passes) may lead to elevated fire weather concerns across our CWA (County Warning Area) beginning Friday into the weekend as an "inside slider" pattern develops. However, the European model disagrees with this and does not show the upper level low strengthening quite as much or becoming cut off over the Four Corners. Current ensemble cluster analysis agrees more with the upper level low progression described by the European model but, given the scenario described by the GFS, it is worth being aware of and paying attention to the potential for elevated fire weather concerns next weekend. Marine (Tonight through next Friday) Issued at 1047pm PDT Sat Oct 12 2024 Seas will continue to abate over the next 24 hours before building to become rough again by Monday afternoon. Long, moderate swell with a period of 13-17 seconds is forecast through Tuesday. A strong storm system will bring near gale force gusts by Wednesday. Beaches Issued at 1133am PDT Sat Oct 12 2024 Long period northwesterly swell of around 12 to 15 seconds with wave heigheights approaching 10 feet will briefly translate to a moderate risk of sneaker waves. This will mainly, though not limited to, be for areas across coastal Sonoma and Marin counties late Monday afternoon/early evening. Those planning on heading to beaches should be cognizant of the potential dangers. Check with local officials and lifeguard personnel before recreating in the water. NOAA San Francisco Bay Area Office: Watches - Warnings - Advisories CA...None. PZ...None. |
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