Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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824 FXUS66 KMTR 300833 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 133 AM PDT Sun Jun 30 2024 ...New SYNOPSIS, SHORT TERM, LONG TERM, FIRE WEATHER... .SYNOPSIS... Issued at 129 AM 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... (Today and tonight) Issued at 129 AM PDT Sun Jun 30 2024 An upper level trough is currently impacting the region and will result in near to slightly above seasonal average temperatures this afternoon. Mostly sunny conditions are expected once any low clouds that do develop dissipate. Tonight, expecting temperatures to cool into the 50`s across much of the region while the higher elevations remain in the 60`s to lower 70`s. 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... (Monday through Saturday) Issued at 129 AM PDT Sun Jun 30 2024 On Monday ridging will begin to build over the region from the west and continue to shift eastward throughout the week. Monday kicks off the first day in a stretch of well above average temperatures with far interior areas (e.g. Pinnacles National Park and Lake Berryessa) likely to reach 100F. Tuesday and Wednesday (as currently forecast) are expected to be the warmest days of the week with afternoon highs expected to be well into the 100s for inland areas, nearing 110F for areas such as northern Napa and Sonoma counties, eastern Contra Costa and Alameda counties, and southern Monterey and San Benito counties. As such, we have upgraded the watch to an Excessive Heat Warning for interior parts of the North Bay, East Bay, South Bay, Santa Cruz Mountains, and interior portions of Monterey and San Bentio counties. Locations in and around the San Francisco Bayshore, Northern Monterey Bay, and Northern Salinas Valley are in a Heat Advisory as temperatures are expected to range from the lower 80`s to mid 90`s (especially around the San Francisco Bayshore). Coastal areas will continue to see temperatures ranging from the upper 60s to the mid 80`s. As such, coastal areas including the City of San Francisco are not included in any advisories or warnings (this is subject to change as we move through this heat event). Overnight minimum temperatures will be an issue with this event as well, with elevations above about 1000 feet struggling to cool below about 75- 80F starting Tuesday morning. Lower elevations will still see some degree of marine influence, but by Thursday morning will only cool into the 60s. 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 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... (06Z TAFS) Issued at 1024 PM PDT Sat Jun 29 2024 IFR-LIFR ceilings along a patch of the northern Monterey Bay coastline, with moderate to high confidence that it expands into the Monterey Bay terminals through the night. Otherwise, generally high confidence of VFR into Sunday evening, with breezy and gusty onshore winds developing in the afternoon. Marginal LLWS concerns continue in the overnight hours as surface winds decouple from flow aloft, but the magnitude is not severe enough to note in the TAFs. Ensemble model output is starting to suggest stratus coming through the San Mateo peninsula into the northern SF Bay terminals late Sunday night and Monday morning, but confidence is low at this time. Vicinity of SFO...VFR through at least Sunday evening. Northwest winds remain breezy overnight before strengthening Sunday afternoon. Gusts could reach 30 knots, but low confidence that they will reach 35 knots or above at this time. Some model output suggests some IFR- LIFR stratus will flow over the San Mateo peninsula and impact the terminal late SUnday night into Monday morning, but confidence is low the TAF remains VFR throughout. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...IFR-LIFR ceilings are expected over the terminals at some point tonight but confidence in timing is low to moderate. Current thinking is for the stratus deck currently blanketing the northern Monterey Bay coast to expand over the terminals sometime after midnight, then mix out through Sunday morning. Breezy onshore winds develop Sunday afternoon, and diminish into the evening as stratus returns to MRY. && .MARINE... (Tonight through next Friday) Issued at 1024 PM PDT Sat Jun 29 2024 Surface high pressure over the Eastern Pacific Ocean will be the driving feature through the period. Northwesterly breezes with occasional gale force gusts will prevail through the weekend. As the aforementioned surface high pressure builds on Monday, the pressure gradient will tighten and 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 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 from 3 PM this afternoon to 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 from 3 PM this afternoon to 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 from 9 AM this morning to 9 PM PDT this evening for Pigeon Pt to Pt Pinos 0-10 nm. Small Craft Advisory from 9 AM this morning to 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 9 AM PDT Monday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...RGass LONG TERM....RGass/Behringer/Clouser AVIATION...DialH 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