Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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835 FXUS66 KMTR 120010 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 510 PM PDT Sat May 11 2024 ...New AVIATION, MARINE... .SYNOPSIS... Issued at 245 PM PDT Sat May 11 2024 Warm temperatures persist through the weekend, with mostly clear skies expected. Stratus will create cloudy conditions for areas near the Bay and coastline. Patchy fog possible near the Monterey Bay and San Mateo coastlines early tomorrow morning. Warm temperatures and low heat risk persist through the upcoming work week. && .SHORT TERM... (This evening through Sunday) Issued at 245 PM PDT Sat May 11 2024 Its another beautiful May day with warm temperatures in the upper 80s expected throughout most inland areas today (perhaps a few low 90s scattered here and there), with mid to upper 60s expected for highs along the coast through the weekend. Clear skies prevail through much of the forecast period, though coastal stratus and fog will impact much of the coastline overnight as stratus trickles inland. Areas around the Monterey Bay, Salinas Valley, SF Bay, and Sonoma coast are likely to see overcast skies tonight as a result of this stratus, thereby reducing any chances of aurora viewing. Yep, that`s right, you heard that correctly! Another chance for viewing the Aurora Borealis will be possible tonight for areas that remain clear, namely areas further inland away from the coastline or higher in elevation above the fog and stratus if you live in a more coastal zone. However, keep in mind that it is only a chance! Although the ongoing increased solar activity increases our chances of seeing the auroras this far south, it is not by any means a guarantee. So cross your fingers and hope for the best! That being said, how about a few aurora-viewing tips? -Look to the northern horizon. -Go to a very dark area where there is little cloud cover and little light pollution. Ideally, a more rural area away from city lights. -Take a few minutes to sit in the darkness and let your eyes adjust. If the auroras are to be seen, you`ll spot them best after waiting 5- 10 minutes as your eyes will be better attuned to pick up any dim lights, such as the auroras. -If you still cannot see them after letting your eyes adjust, try using a long exposure camera, or a phone camera on the nighttime setting. If your eyes don`t pick it up first, your iphone (or android) surely will! Although we in this particular office do not predict space weather (just Earth weather!), for further information about what is causing these auroras, we can point you to the right people to answer those questions. For further information about the chances of seeing the Aurora Borealis and the current geomagnetic storm, please take a look at the Space Weather Prediction Center`s social media pages (@NWSSWPC) or visit their web page at spaceweather.gov . && .LONG TERM... (Sunday night through next Friday) Issued at 245 PM PDT Sat May 11 2024 Warm temperatures continue through much of the upcoming work week, though cool off towards the latter half by a few degrees to reach more seasonable temperatures. Expect high temps to be predominantly in the low to mid 80s for interior regions, with upper 50s and lower 60s along the coast line. Heat Risk is expected to be low for most regions, with only the most sensitive populations at risk for any heat-related illnesses. Nighttime lows will be comfortable in the low to mid 50s for most regions. Current CPC outlook places our region the next 6-10 days leaning slightly above normal for temperatures. && .AVIATION... (00Z TAFS) Issued at 510 PM PDT Sat May 11 2024 VFR transitioning to MVFR-LIFR overnight. Widespread stratus is expected to return inland at all sites except LVK overnight. Similar to last night, the marine layer will be fairly shallow with forecast vertical wind profiles generally showing more moist air below 1500 feet and drier air above it. SFO, OAK, and SJC are leaning towards MVFR with stratus heights between 1000-1500 feet. STS, APC, MRY, and SNS are leaning more towards LIFR to IFR heights between 300-700 feet with LIFR heights becoming more likely by mid-morning around 12Z. At this time, weaker, variable winds and higher RH values are expected by mid-morning which could support fog development particularly at STS, MRY, and SNS. VFR conditions will return by late morning with most guidance suggesting 17-19Z as the general timeframe for clearing. Moderate NW winds will return during the afternoon with stratus looking to return just after the end of this TAF period. Vicinity of SFO...VFR transitioning to MVFR overnight. Moderate NW winds will weaken and become more westerly overnight. Widespread stratus is expected to move inland tonight with MVFR conditions expected by mid-morning. Most models show stratus moving in along the coast and into the SF Bay earlier in the morning before filling in over SFO. Continued stratus arrival at 12Z due to this pattern but if stratus fills in faster an arrival time closer to 09-10Z may be possible. Moderate confidence that stratus farther inland will be closer to 1000-1500 feet but, given the shallow nature of the marine layer, a lower ceiling developing is not out of the question. Will continue to monitor and adjust as needed for the next TAF issuance. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR transitioning to LIFR overnight. Similar to last night, a shallow marine layer will keep stratus ceilings fairly low with heights between 300-700 feet possible. Fog becomes more likely heading into the mid-morning hours (11-12Z) as weaker, variable winds and increased RH values prevail. If fog does develop, visibilities are likely to drop below 1SM. Conditions will improve by late morning with moderate NW winds and VFR through the end of the TAF period expected. && .MARINE... (Tonight through next Friday) Issued at 510 PM PDT Sat May 11 2024 Widespread stratus continues over the inner coastal waters and is expected to spread over the majority of the inner and outer coastal waters overnight into tomorrow morning. Fair weather and moderate northwesterly breezes and the occasional fresh gusts continue through the end of the weekend. Winds begin to increase Monday as surface high pressure over the Eastern Pacific Ocean builds and moves east, keeping things dry with northwest winds increasing to a fresh breeze, particularly over the outer waters, North Bay Coast, and Big Sur Coast. For the Big Sur Coast, a coastal jet looks to develop beginning Sunday through the mid work week. Significant wave heights will also begin building as a result at the start of next week, reaching maximum heights of 12-15 feet, before diminishing by the late work week. && .BEACHES... Issued at 719 PM PDT Fri May 10 2024 Long period southwest swell will lead to slightly elevated chances for sneaker wave and rip current development this weekend. Conditions are expected to stay below Beach Hazards Statement criteria as swell height will only be between 1-2 feet. However, in light of anomalously warm temperatures and increased likelihood of people traveling to the coast, visitors to the beach should remember to take safety precautions to prevent being caught by an unexpected large wave and to never turn your back on the ocean. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ SHORT TERM...AC LONG TERM....AC AVIATION...Kennedy MARINE...Kennedy 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