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Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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983 FXUS66 KMTR 011647 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 947 AM PDT Mon Jul 1 2024 ...New UPDATE, MARINE... .SYNOPSIS... Issued at 255 AM PDT Mon Jul 1 2024 The warm up begins today and will ramp up on Tuesday with excessive heat across the interior through the upcoming weekend. Increased fire danger this week as well with temperatures well above normal and dry conditions through out the forecast period. && .UPDATE... Issued at 937 AM PDT Mon Jul 1 2024 Starting off the day a few degrees cooler compared to 24 hours ago across lower elevations. That will quickly change going into tomorrow as the marine layer continues to compress under the strong high pressure aloft. These changes can already be seen in the higher elevations, as these areas are starting the day slight warmer than 24 hours ago. As such, will leave today`s forecast temps alone in anticipation of the strong warming aloft this evening into tomorrow. A notable change this morning...The City of San Francisco has been added to the Heat Advisory for Tuesday and Wednesday as forecast high temps are being nudged slightly higher. Current forecast for the city each day calls for highs in the mid-80s, but the 90th percentile high temp is around 89-91 each day. The higher temps being in the southern and eastern parts of the city. As such, HeatRisk is moderate for the eastern portion of the city Tuesday and Wednesday. && .SHORT TERM... (Today and tonight) Issued at 255 AM PDT Mon Jul 1 2024 The much anticipated warm up begins today with temperatures across the interior warming into the mid-to-upper 90`s with a few spots reaching the triple digits. Meanwhile, coastal areas will remain cool for another day with maximum temperatures warming into the 60`s and 70`s as a shallow marine layer remains in place. Elsewhere, look for high temperatures to be in the upper 70`s to lower 90`s just inland away from the coast. For tonight, expecting minimum temperatures to cool only into the mid 50`s to mid 60`s in most major urban areas with upper 60`s to mid 70`s in the hills and potentially lower 80`s in the peaks. && .LONG TERM... (Tuesday through Sunday) Issued at 255 AM PDT Mon Jul 1 2024 A more robust warming trend begins on Tuesday as a strong ridge of high pressure builds over the West Coast. This looks to continue through much of the week if not into next week under the influence of the high pressure. No major changes to the Heat Advisory or Excessive Heat Warning other than to extend it out into Saturday evening. Inland areas within the Warning, especially the higher terrain, will see limited overnight relief with temperatures remaining in the 70`s to 80`s while lower elevations cool more sufficiently. Heat Safety and Impacts: By now youre well aware that it is going to be extremely hot this week with well-above normal temperatures; now lets talk about the impacts of excessive heat and actions we can take to minimize those impacts: With extreme heat, and especially prolonged heat events, it is a marathon, and not a sprint. Our bodies, infrastructure, pets, and livestock will be under duress from heat over the span of days as opposed to just a day or two. Given that there is little overnight relief expected throughout this event, this is where it really becomes a marathon, and precautionary measures are necessitated in order to prevent adverse results such as heat exhaustion and stroke. This is not just for individuals sensitive to heat, but rather, the entire population. Heat for this duration and at these temperatures can be dangerous for everyone. Do your body a favor and if you can, suspend outdoors activities between the hours of 10am and 7pm on days where Heat Advisories or Excessive Heat Warnings are in effect. Remain in air conditioning if you have that available to you in your residence, or seek out air conditioned environments such as stores, movie theaters, restaurants, libraries, and cooling shelters. If you cannot access air conditioned environments, must be outside, work outdoors, or otherwise, there are other precautionary measures you can take to keep yourself and your loved ones safe (including pets!) during excessive heat. Take frequent breaks in the shade and ensure that you are drinking plenty of cool water, or other hydrating beverages such as sports drinks with electrolytes. Avoid DEHYDRATING drinks such as alcohol or caffeinated beverages. That aside, visiting your city public pool or a lake, river, or ocean can also help keep you cool, but dont forget the life jacket! If planning on swimming, stick to where there is a lifeguard, and know the ocean or river conditions before you get in. Although outside of our area, its worth repeating: rivers can run fast and cold with snowmelt in the Sierra Nevada mountains, and cold water shock can set in quickly, which can lead to loss of muscle control, and ultimately, drowning. Cold water shock can also set in for ocean- goers. Have fun at the water, but be smart, be safe, and Know Before You Go! Finally, if you do not have air conditioning or cannot access it, and also cannot access a body of water to stay cool: consider taking cold showers or baths, turn on those sprinklers or garden hose and have a fun time in your own makeshift water park, or lay a damp, cool towel across your head or body. Even just dipping your hands and feet in cool water can help to abate feelings of excessive heat. For pets and livestock, make sure they have access to shade structures or areas, and have clean water freely available to them at all times. They do not have the same resources or ability to notify of feeling heat-stressed as we do, so check in on them! If theyre permanently outdoors, consider giving them a quick rinse- down with the hose or set up misters, as the evaporation will help to keep them cool as well. && .AVIATION... (12Z TAFS) Issued at 417 AM PDT Mon Jul 1 2024 IFR-LIFR ceilings persist at the immediate coast south of the Golden Gate, the Monterey Bay region, and down the Salinas Valley, expected to retreat to the coast after sunrise. Confidence in models showing stratus at SFO and OAK this morning remains low. Breezy onshore winds will develop this afternoon, continuing into the evening as stratus returns to the Monterey Bay region. Low confidence for stratus development tonight through Tuesday morning into the SF Bay and Napa Valley. Marginal LLWS concerns continue during the overnight periods, especially at the coast and in the North Bay. Vicinity of SFO...Moderate to high confidence of VFR through the TAF period. Breezy west-northwest winds will continue through the morning before building again Monday afternoon as gusts reach 20-25 knots. Winds diminish in the evening. Very low confidence for stratus at the terminal tonight into Tuesday morning. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...IFR-LIFR ceilings continue to impact the terminals, clearing late Monday morning. Breezy northwest flow develops this afternoon with gusts up to 20 knots at SNS, with stratus building back into the coastal regions this evening, expanding inland later through the night. && .MARINE... (Today through Saturday) Issued at 937 AM PDT Mon Jul 1 2024 Strong northwesterly breezes continue over the outer waters through the midweek. Winds become more northerly this afternoon and gale force to near gale force gusts become more widespread over the outer waters as high pressure builds. Winds will gradually weaken by mid to late week and become moderate to fresh. Significant wave heights generally build to 10-12 feet through mid-week before abating by the late week. Portions of the northern outer waters may see peak wave heights between 12-16 feet through mid-week. && .FIRE WEATHER... Issued at 901 PM PDT Sun Jun 30 2024 ...A Red Flag Warning is in effect from Monday evening through Tuesday evening for the East Bay Hills, Marin and Sonoma Coastal Ranges, and the North Bay interior mountains Monday evening through late Wednesday afternoon. A Red Flag Warning has been added to the list of hazards along with the Excessive Heat Warning which remains in place for most of our interior locations, and a Heat Advisory for some locations closer to the shoreline that may still see minimal influence of the Marine Boundary Layer. Minimum RH values inland for the upcoming week and beyond will mostly be in the teens, with some single digit values in areas of higher elevation. Overnight RH recover will be poor to non-existent as the heat wave persists through the week, and potentially into next weekend. The hot and dry conditions continue to move ERCs into the 70-80 percent range. With the long holiday weekend, and the many outdoor activities expected, people need to be careful with any campfires, and fireworks should not be used. Any wildfire that ignites will have the potential for rapid spread. Lightning is the only natural ignition for wildfires and there are no thunderstorms in the forecast. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Heat Advisory from 11 AM Tuesday to 7 PM PDT Wednesday for CAZ006. Red Flag Warning from 11 PM this evening to 11 PM PDT Tuesday for CAZ502-503-515. Excessive Heat Warning from 11 AM Tuesday to 8 PM PDT Saturday for CAZ502>504-506-510-512>518. Red Flag Warning from 11 PM this evening to 5 PM PDT Wednesday for CAZ504. Heat Advisory from 11 AM Tuesday to 8 PM PDT Saturday for CAZ508- 528-529. PZ...Small Craft Advisory until 3 AM PDT Tuesday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory until 9 PM PDT this evening for Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena to Pt Reyes 10-60 NM. Gale Warning from 3 PM this afternoon to 3 PM PDT Tuesday for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...RGass LONG TERM....RGass AVIATION...DialH 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