Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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772 FXUS66 KMTR 292306 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 406 PM PDT Sat Jun 29 2024 ...New AVIATION, MARINE... .SYNOPSIS... Issued at 1226 PM PDT Sat Jun 29 2024 Significant warm up still on the way for next week after near normal temps this weekend. Increased fire danger next week as well with temps well above normal and dry conditions through into next weekend. && .SHORT TERM... (This evening through Sunday) Issued at 1226 PM PDT Sat Jun 29 2024 Warm today and tomorrow with temps near to slightly above normal. Good onshore flow into Sunday as a weak trough sits over the West Coast. Still warm over the next couple of days, but this weekend will be a great time to finish up outdoor chores if you live in interior areas before the warm up begins on Monday. && .LONG TERM... (Monday through next Friday) Issued at 1226 PM PDT Sat Jun 29 2024 By late in the weekend, the weak trough begins to break down and becomes replaced by a robust upper ridge that parks itself over the western US through late week. Monday kicks off the first day in a stretch of well above average temps. Locations far inland may see the 100 degree mark on Monday, with an even more significant increase on Tuesday. An Excessive Heat Watch is in effect for inland areas away from the coast beginning Tuesday and lasting through Friday. The whole period will be hot, but it looks like Wednesday may be the peak just by a few degrees based on the current forecast. Afternoon highs Wednesday are expected to be well into the 100s for inland areas, nearing 110 for areas such as northern Napa and Sonoma counties, eastern Contra Costa and Alameda counties, and southern Monterey and San Benito counties. Other urban areas can expect temps ranging from 90-100, and closer to 80-85 for areas along the immediate Bay shoreline. Coastal areas will continue to see temps ranging from the upper 60s to the upper 70s. Overnight lows will be an issue with this event as well, with elevations above about 1000 feet struggling to cool below about 75-80 starting Tuesday morning. Lower elevations will still see some degree of marine influence, but by Thursday morning will only cool into the 60s. Climatologically, this event is significant in that the forecast 850mb temps and 500mb heights are well above the the percentile and near daily records for this time of year based on KOAK soundings. For July 4, which is when these values are expected to peak based on the current forecast, the daily record max 850mb temp and 500mb height are 27.4 C and 597 dm, respectively. The forecast mean from the ECMWF ensemble for each of these is about 28 C and 598 dm. There is considerable uncertainty regarding the pattern after Friday, but the possibility remains that the ridge hangs out for even longer, thus will prompt the need to extend heat-related messaging into next weekend. Heat Safety and Impacts: By now youre well aware that it is going to be extremely hot next 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 Excessive Heat Watches or 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. AC && .AVIATION... (00Z TAFS) Issued at 403 PM PDT Sat Jun 29 2024 Currently VFR at all terminals with stratus hugging a majority of the coastline. High confidence in VFR through the TAF period except at the Monterey Bay terminals of MRY and SNS. Winds will remain onshore through the TAF period. While below LLWS criteria, it may be bumpy getting out of the region through tomorrow morning as winds aloft are more northerly. Vicinity of SFO...Currently VFR with northwesterly flow. High confidence in VFR through the TAF period. Winds will prevail out of the west through the TAF period with gusts up to 30 knots to be expected through the day today as well as tomorrow afternoon and evening. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Currently VFR with westerly flow at MRY and VFR with northwesterly flow at SNS. Winds will prevail out of the west for MRY and out of the northwest for SNS through the TAF period. Moderate to high confidence in low-end IFR ceilings returning to both terminals overnight. SNS is expected to clear by mid-morning with MRY following suit by the afternoon. && .MARINE... (Tonight through next Thursday) Issued at 403 PM PDT Sat Jun 29 2024 Strengthening surface high pressure over the Eastern Pacific Ocean will be the dominating feature through the period. Northwesterly breezes with occasional gale force gusts will prevail through the weekend. As the pressure gradient tightens Monday, breezes will become northerly with gale force gusts to be expected over the outer waters through Wednesday. Significant wave heights build to 10-15 feet through Tuesday before beginning an abating trend towards the end of the period. && .FIRE WEATHER... Issued at 302 PM PDT Sat Jun 29 2024 Fire weather concerns will elevate this upcoming week. An Excessive Heat Watch remains in effect for most of our area away from the coastline for Tuesday through Friday. ERCs are quickly shifting into the 70ish percentiles and higher in areas prone to grass fires. The high heat and subsequent low RH values, poor overnight RH recovery and the associated risks of fireworks with the Fourth of July - all makes for a combustible situation, please plan accordingly. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Excessive Heat Watch from Tuesday morning through Friday evening for CAZ502>504-506-508-510-512>518-528. PZ...Small Craft Advisory from 3 PM to 9 PM PDT Sunday for Mry Bay. Small Craft Advisory until 3 PM PDT Sunday for Pt Arena to Pt Reyes 0-10 nm. Gale Warning from 3 PM to 9 PM PDT Sunday for Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory until 3 AM PDT Monday for Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory from 9 AM to 9 PM PDT Sunday for Pigeon Pt to Pt Pinos 0-10 nm. Small Craft Advisory from 9 AM Sunday to 9 AM PDT Monday for Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 9 AM PDT Monday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Behringer LONG TERM....Behringer AVIATION...Sarment MARINE...Sarment 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