Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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011 FXUS66 KMTR 030650 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1150 PM PDT Sun Jun 2 2024 ...New AVIATION... .SYNOPSIS... Issued at 1254 PM PDT Sun Jun 2 2024 Cooler temperatures hang on through Monday with breezy daytime winds and marine layer stratus overnight. Tuesday sees a dramatic warmup with a Heat Advisory in effect for the inland areas through Thursday. Temperatures will moderate towards the latter part of the week. && .UPDATE... Issued at 842 PM PDT Sun Jun 2 2024 For the most part, another seasonably cool day around the Bay Area and Central Coast with highs topping out in the upper 50s to 70s along the coast/bays and 70s to mid 80s inland. Additionally, it was a mixed bag with some sites warmer and some sites colder than Saturday. The variability was likely tied to persistent onshore flow and increasing high level clouds. The bigger story for the day were the winds. The onshore gradient from SFO-SAC may have eased a little, but still saw some impressive winds today. A sampling of the peak winds had a few sites 50-55 mph in SF Peninsula and East Bay Hills. Other gaps and passes weren`t as strong, but still gusting 25-40 mph. No real update needed in the near term. A weak cold front currently spreading light rain across far NorCal continues to move slowly southward. The tail end of the feature will clip the North Bay late tonight and early Monday brining a low chance (15-20%) of 0.01 rain. The more likely scenario will be more widespread drizzle that may accumulate along the coast and coastal terrain. Otherwise, the marine layer lurking over the coastal waters and immediate coast will make its nightly march inland. MM && .SHORT TERM... (This evening through Monday) Issued at 1254 PM PDT Sun Jun 2 2024 Coastal stratus lingers over the western San Mateo Peninsula, with some cloud cover slipping through the San Bruno Gap, and in the southern Monterey Bay region. Expect the remaining cloud cover over the SF Bay region to dissipate through the rest of the afternoon and brief, if any, clearing for the coastal regions. Stratus returns inland tonight with the potential for gloomy skies through Monday, as the fringes of a cold front that impacts the Pacific Northwest come through the region. High resolution model output is showing some chance (10-20% PoP) for showers in the Sonoma coastal ranges, and coastal drizzle elsewhere, but accumulations are expected to remain very light, up to a few hundredths of an inch at most. Northwest winds are picking up around the region and gusts will top out at 20 to 30 miles per hour across the gaps and passes. These winds are expected to diminish tonight before picking up again on Monday. Today`s highs will be in the upper 50s to lower 60s along the Pacific coast, the mid 60s to lower 70s in the Bayshore, and generally in the upper 70s to lower 80s across the inland valleys. The North Bay and southern Monterey County valleys will see highs rising into the mid to upper 80s. Low temperatures tonight will hover in the mid 50s to lower 60s, and Monday`s highs should be similar to today`s, except in the North Bay where the frontal influence will drop high temperatures to the upper 70s to around 80. && .LONG TERM... (Monday night through next Saturday) Issued at 1254 PM PDT Sun Jun 2 2024 Tuesday sees a pattern change as a subtropical high building in the eastern Pacific comes into the region, warming temperatures to well above the seasonal averages. A Heat Advisory is in effect for Tuesday through Thursday for the interior North Bay and East Bay, and Wednesday through Thursday for the South Bay and interior mountains of the Central Coast, where high temperatures rise into the 90s to the lower 100s and lows hover in the low to mid 60s, perhaps around 70 in the warmest locations. There`s still a fair bit of uncertainty in how the warmth will translate to the coast, in particular how the marine layer and onshore winds will impact coastal temperatures. The current forecast calls for temperatures in the upper 70s to lower 80s along the Bayshore and the mid 60s to lower 70s along the Pacific coast. Moderate HeatRisk is expected for the inland North Bay, the East and South Bays, and the inland Central Coast through Thursday, meaning that there`s a moderate risk of heat-related illnesses for sensitive populations (children, the elderly, pregnant women, those with certain medical conditions, or anyone working outside without cooling or hydration). In addition, we`re also starting to see major HeatRisk in some areas of the North Bay valleys and far eastern Contra Costa county on Tuesday, corresponding to a major risk of heat-related illnesses to anyone without effective cooling, adequate hydration, or both. Here are some heat safety tips: * Stay hydrated and drink plenty of fluids. * Wear lightweight, light-colored clothing. * Reduce time spent outdoors or stay in the shade. * Never leave people or pets unattended in vehicles. * Use sunscreen if going to the coast or the pool. A gradual cooling trend is expected to begin later in the week as the high starts to crawl towards the east, with the large scale pattern hinting at a possible southerly wind reversal. By the upcoming weekend, high temperatures are expected to moderate to the low to mid 80s for the inland valleys and the upper 50s to mid 60s closer to the coast. && .AVIATION... (06Z TAFS) Issued at 1150 PM PDT Sun Jun 2 2024 Coastal stratus will continue to push inland through much of the night, bringing low IFR CIGs for many terminals. Models do suggest CIGs even dipping into LIFR territory, though confidence on this is only moderate for the SF Bay region. However, with an approaching ridge, this could lead to compression, thereby lowering CIGs, so it is not entirely out of the question that CIGs could go LIFR. Therefore, have decided to include LIFR CIGs in select TAF sites for now, though this will be something to keep an eye on through the night. Into the afternoon tomorrow, moderate westerly winds return, though gusts will likely be isolated to coastal terminals, reaching about 20-25 knots. Clearing to VFR is expected to be late for most, occuring in the afternoon as winds begin to increase. Vicinity of SFO...Currently IFR. Moderate confidence in becoming LIFR into the later overnight hours. High clouds will also be present through the morning. Late clearing of stratus is expected in the afternoon time, VFR but with SCT low clouds as winds increase and gust to around 30 knots out of the west. Clouds are anticipated to continue to dissipate through the end of the TAF period leading to widespread VFR. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...IFR conditions persist through much of the night, becoming LIFR in the early morning of Monday. Stratus will begin to lift again near sunrise, eventually becoming MVFR in the late afternoon. Not expecting clearing to VFR tomorrow, so have left CIGs in the TAF. Westerly winds breezy in the afternoon tomorrow, then easing into the late night. && .MARINE... (Tonight through next Friday) Issued at 442 PM PDT Sun Jun 2 2024 The gradient between subtropical high pressure over the Pacific and lower pressure over the Intermountain West is maintaining a fresh to strong NW breeze. Buoys are reporting wind gusts as high as 30 kts, on an increasing trend this evening. These conditions will last well into the night. Moderate wave heights will persist through Monday night before rough seas arrive mid-week. && .CLIMATE... Issued at 127 AM PDT Sat Jun 1 2024 Record high temperatures at the long term climate stations for June 4th and 5th: Station June 4th June 5th Santa Rosa 98 in 1949 102 in 1926 Kentfield 101 in 1981 102 in 1926 Napa 102 in 1981 105 in 1903 Richmond 90 in 1955 86 in 1983 Livermore 105 in 1960 104 in 1926 San Francisco 92 in 1949 95 in 1883 SFO Airport 92 in 1955, 1949 89 in 1972 Redwood City 100 in 1981 97 in 2002, 1972 Half Moon Bay 71 in 1955 74 in 1958 Oakland downtown 96 in 1981 87 in 2002 San Jose 98 in 1904 100 in 1926 Salinas Airport 92 in 1949 87 in 1949 King City 102 in 1981, 1957 105 in 1926 && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Heat Advisory from 8 AM Tuesday to midnight PDT Thursday night for CAZ503-504-506-510-515. Heat Advisory from 8 AM Wednesday to midnight PDT Thursday night for CAZ513-514-518. PZ...Small Craft Advisory from 3 PM to 9 PM PDT Monday for Mry Bay. Small Craft Advisory until 3 AM PDT Monday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory from 3 PM Monday to 9 AM PDT Tuesday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm- Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory from 3 PM Monday to 3 AM PDT Tuesday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 3 AM PDT Tuesday for Pt Pinos to Pt Piedras Blancas 0-10 nm. && $$ SHORT TERM...DialH LONG TERM....DialH AVIATION...AC MARINE...Flynn 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