Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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773 FXUS66 KMTR 302037 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 137 PM PDT Sun Jun 30 2024 ...New SYNOPSIS, SHORT TERM, LONG TERM... .SYNOPSIS... Issued at 1235 PM PDT Sun Jun 30 2024 Significant warm up still on the way for next week after near normal temperatures this weekend. Increased fire danger next week as well with temperatures well above normal and dry conditions through next weekend. && .SHORT TERM... (This evening through Monday) Issued at 1235 PM PDT Sun Jun 30 2024 A gorgeously warm day across the region today, and a great day to be outside. Temps warm up a few degrees going into Monday as a weak upper level trough degrades and moves inland. Highs Monday look to be in the 90s across the interior, 80s for much of the Bay shoreline, and 70s along coastal areas. If you live in the interior, now is the time for any outdoor chores you may need to get done before the warm up begins on Monday. && .LONG TERM... (Tuesday through next Saturday) Issued at 1235 PM PDT Sun Jun 30 2024 Significant warmup really begins Tuesday as the very strong ridge settles in across the West Coast. Not much change in the forecast through the middle part of the week. Excessive Heat Warning goes into effect Tuesday morning for interior areas, while lower elevation locations that were once in the Watch have been converted to a Heat Advisory given that they will cool off a little more efficiently at night. Inland and high elevation areas in the Warning will not see as much overnight relief through the end of the week. Compressional heating under the ridge will warm the airmass to near daily record territory above what little will be left (if anything at all) of the marine layer. Guidance continues to advertise 850 mb temps around 28 C, peaking Wednesday. The daily max moving average this time of year is about 26.7 C, and we will be well above the 90th percentile, which is about 23 C. Did nudge high and low temperatures up by a couple of degrees Wednesday into the weekend as of this afternoon forecast package. Far inland areas may actually end up with triple digits into the weekend and the start of the next week. Left the timing of the heat hazards as is for now (expiring Friday night), but will definitely need to look into extending the Excessive Heat Warning through the weekend. Cluster analysis still shows rather high uncertainty regarding the breakdown of the ridge into next week, hence the decision to wait on extending the hazards until we become more confident over the next couple of days. 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. && .AVIATION... (18Z TAFS) Issued at 1154 AM PDT Sun Jun 30 2024 VFR through the TAF period for the majority of terminals, the exception being Monterey Bay. W/NW moderate and gusty winds persist through the afternoon and evening today. Gusts are generally expected to be in the 20-25 knot range. Gusty winds slowly ease into the late night to become light for most terminals. Vicinity of SFO...VFR through the TAF period. Moderate W/NW winds will persist through the late night accompanied by strong gusts into the 30-35 knot range. Although gusts will eventually diminish into the late night tonight, winds will remain breezy into Monday morning. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR through the late evening today, with breezy onshore winds and occasional gusts near 20 knots. Models indicate the return of stratus late this evening, however, with building high pressure, and light offshore winds overnight, there remains some question as to whether the marine layer and stratus will be eroded from the coastline, preventing a return of CIGs overnight at KMRY and potentially KSNS. As it currently stands, have IFR/LIFR CIGs developing at KMRY overnight though confidence on this development is only moderate. What is confident is CIG altitudes (should they develop), as high pressure should keep CIGs "squished" and confined with only a few hundred feet of the surface. Any stratus that does form over the terminals is expected to clear by the late morning of Monday. && .MARINE... (Today through Friday) Issued at 1154 AM PDT Sun Jun 30 2024 The sea state continues to be largely wind driven today with only light northwesterly and southerly swell present throughout the waters. Strong northwesterly breezes with occasional gale force gusts will continue today and through the mid-week. As high pressure builds on Monday, the pressure gradient will tighten leading to more widespread near-gale force gusts across the waters. Breezes will also turn to become slightly more northerly. Significant wave heights build to 10-12 feet generally through the mid-week before beginning an abatement trend. && .FIRE WEATHER... Issued at 129 AM PDT Sun Jun 30 2024 ...Critically low relative humidity expected across the interior and in higher terrain this upcoming week, especially Tuesday and Wednesday... Fire weather concerns will elevate this upcoming week. A Heat Advisory and Excessive Heat Warning 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 Warning from 11 AM Tuesday to 11 PM PDT Friday for CAZ502>504-506-510-512>518. Heat Advisory from 11 AM Tuesday to 11 PM PDT Friday for CAZ508- 528-529. PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay. Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena to Pt Reyes 0-10 nm. Gale Warning until 9 PM PDT this evening 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 until 9 PM PDT this evening for Pigeon Pt to Pt Pinos 0-10 nm. Small Craft Advisory until 9 PM PDT Monday for Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 3 PM PDT Monday for Pt Arena to Pt Reyes 10-60 NM. Gale Watch from Monday afternoon through Tuesday morning for Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory until 3 AM PDT Tuesday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...Behringer LONG TERM....Behringer AVIATION...AC 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