Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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915 FXUS66 KMTR 050555 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1055 PM PDT Thu Jul 4 2024 ...New AVIATION... .SYNOPSIS... Issued at 1217 AM PDT Thu Jul 4 2024 Day 3 of the heat wave. Extremely hot conditions will continue through the middle of next week for inland areas. Excessive Heat Warnings, Heat Advisories, and Red Flag Warnings are in effect. && .UPDATE... Issued at 819 PM PDT Thu Jul 4 2024 Once again, records were either tied or broken this afternoon at San Rafael and the San Francisco International Airport (see below). However, slight cooling was observed across the board this afternoon. Low clouds and/or fog are widespread off of the entire Bay Area and Central Coast and are likely to spread locally inland tonight given the shallow marine layer. Tonight, temperatures will lower into the mid 50`s to lower 60`s in coastal areas and cooler interior valleys, mid 60`s in the warmer valleys (such as the southern Santa Clara Valley), and upper 60`s to mid 80`s in the higher terrain. Again, this will provide very little relief from today`s heat. ...RECORD HIGH TEMPERATURES THURSDAY, JULY 4, 2024... LOCATION HIGH PREVIOUS RECORD --------------------------------------------------------------- SAN RAFAEL 98 (TIED) 98 IN 2013 SAN FRANCISCO AIRPORT 87 85 IN 1973 These data are preliminary and have not undergone final quality control by the National Centers for Environmental Information. Therefore, these data are subject to revision. Final and certified climate data can be accessed at www.ncei.noaa.gov. && .SHORT TERM... (This evening through Friday) Issued at 207 PM PDT Thu Jul 4 2024 The center of the dome of high pressure responsible for our extended heat wave has begun moving onshore and will continue to gradually shift east and south over the coming days. Today will be the `coolest` day until possibly the middle of next week, but will offer no relief as the high heat keeps on building, and the impacts will only continue to compound. Elevated locations away from the immediate shoreline are seeing little to no relief wrt overnight temperatures with lows in the 80s, even some higher spots in the 90s. This is something campers and hikers need to be aware of as we continue through the holiday weekend. Temperatures at or just along the immediate shoreline will offer the best chance at beating the heat with highs in the 60s and 70s, otherwise do everything you can to reduce your heat risk. Read below at the bottom of the Long Term forecast for more on how to keep yourself safe. && .LONG TERM... (Friday night through next Wednesday) Issued at 207 PM PDT Thu Jul 4 2024 Saturday appears to be the peak of the heat wave wrt maximum temperatures, but will still be days away from marking the end of the event. Elevated areas across southern Monterey and San Benito Counties will be at or slightly above 115 degrees. There is no end in sight to heat wave in the official extended forest out to next Thursday (July 11th), but looking out at next weekend, troughing is established along the West Coast on the back side of the meandering high as it moves farther inland. As heights and thickness values gradually decrease, so will temperatures, but until then please take note of the following information to keep yourself, family, friends and pets safe from this historic heat wave. Heat is the number 1 weather related killer in the United States. Unfortunately lives will be lost during this heat wave. Follow these tips to protect yourself, your loved ones, and your animals. -Stay inside in an air conditioned environment between 10am and 7pm. -Suspend unnecessary outdoor activities during the extreme heat, but if you must be outdoors, take frequent breaks in the shade or AC and drink cool water. -Know the signs and symptoms of Heat Exhaustion vs. Heat Stroke! Heat Stroke can be deadly if not treated immediately by a medical professional. Call 911 if you suspect someone is suffering from Heat Stroke. -Wear a lifejacket, swim near a lifeguard, and check conditions before entering the water if going to a river or ocean to cool off. Rivers and the ocean are extremely cold, and Cold Water Shock can turn into paralysis and drowning if you are not careful. -Use a cool and damp towel on your body if you do not have AC and are feeling hot. Or, take a cool shower or bath. -Do not leave kids or pets in a parked car. -Ensure pets and livestock have access to shade and water. && .AVIATION... (06Z TAFS) Issued at 1047 PM PDT Thu Jul 4 2024 VFR through the TAF period for all but the immediate coast and the Monterey Bay. High pressure aloft is causing a very shallow marine layer. The good news is this will only affect the coastal terminals overnight, the bad news is the the terminals that do have a ceiling roll in will see very low ceilings in the 200 ft range and possible fog. These CIGS look to last into late Friday morning but erode as widespread moderate to breezy winds return. Winds reduce again into Friday evening. Vicinity of SFO...VFR through the TAF period. Moderate winds last into the night before reducing. Moderate westerly winds return Friday afternoon with some infrequent breezes, but these winds weaken into the night. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Winds reduce into the night as LIFR CIGS move inland and fill over MRY, with SNS filling later into the night. These CIGs erode in the mid to late morning as westerly winds build. Winds reduce again into the evening with CIGs returning later Friday night. There is also some visibility reduction due to a combination of firework smoke and high pressure that may get worse as the temperature drops and fog starts to form. && .MARINE... (Tonight through next Wednesday) Issued at 919 PM PDT Thu Jul 4 2024 Light to moderate winds persist for most areas until the end of the week. Waves continue to reduce before breezy to gusty winds build into Friday in the southern waters, causing hazardous conditions for small craft. && .FIRE WEATHER... Issued at 819 PM PDT Thu Jul 4 2024 Red Flag Warnings are in effect for the Marin and Sonoma Coastal Range until 5 AM Friday. Red Flag Warnings are in effect for the North Bay Interior Mountains, East Bay Hills, and Santa Cruz Mountains until 9 PM Saturday. Red Flag Warnings are in effect for the Santa Lucia Mountains, San Benito County, and the Southern Salinas Valley from 9 AM Friday through 9 PM Saturday. Winds have calmed since yesterday, and are now gusting in the 15-25 mph range at higher elevations. Despite the wind improvement, this prolonged heat wave will continue to bring very low RH that will cure and dry the fuels. ERC values are exceeding or approaching the max moving average for a number of regions. Conditions are dangerous, and we urge extreme caution. Please rethink the use of any fireworks this year, including the safe and sane, or even those seemingly-innocuous sparklers and pop-its. Perhaps consider not lighting them off at all this year, and instead enjoy a professional display in your community, or even on TV. Its not worth the risk. Don`t Be the Spark! && .BEACHES... Issued at 1224 AM PDT Wed Jul 3 2024 Beaches will be a popular destination over the Holiday and as one of the few places to escape the oppressive inland temperatures. Fortunately the waves are relatively low energy, but that doesn`t alleviate all beach safety concerns. Ocean temperatures are in the mid-50s. This cold water may catch some off-guard. Cold water shock can set in very quickly. Wear a life jacket, dress appropriately, limit time in the water, swim near a lifeguard and follow their instructions. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Coastal Flood Advisory until 5 AM PDT Friday for CAZ006-506-508. Excessive Heat Warning until 11 PM PDT Wednesday for CAZ502>504- 506-510-512>518. Red Flag Warning until 5 AM PDT Friday for CAZ502-503. Red Flag Warning until 9 PM PDT Saturday for CAZ504-512-515. Heat Advisory until 11 PM PDT Wednesday for CAZ508-528-529. Red Flag Warning from 9 AM Friday to 9 PM PDT Saturday for CAZ516>518. PZ...Small Craft Advisory from 3 AM Friday to 9 AM PDT Saturday for Pt Pinos to Pt Piedras Blancas 0-10 nm. && $$ SHORT TERM...JM LONG TERM....JM AVIATION...Flynn MARINE...Murdock 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