Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
294 FXUS66 KMTR 131813 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1113 AM PDT Thu Jun 13 2024 ...New AVIATION, MARINE... .SYNOPSIS... Issued at 247 AM PDT Thu Jun 13 2024 Quiet through the rest of the week with slight warm up on Friday across the interior. Near normal temperatures by the weekend. Increasing confidence for high wind potential and increased fire danger Sunday into early next week. && .SHORT TERM... (Today through Friday) Issued at 247 AM PDT Thu Jun 13 2024 Temperatures this afternoon will be similar to those yesterday as zonal flow conditions north of the region while an upper level low remains parked off of southern California. Temperatures this afternoon will range from the upper 50`s to 60`s near the coast and bayshore, 70`s to near 80 degrees just inland and into the East Bay, Santa Clara Valley, and southern Salinas Valley. The regions farthest interior will reach into the upper 80`s to low 90`s. Tonight, expecting less widespread stratus to penetrate inland as the marine layer begins to compress. Overnight low temperatures are forecast to be in the upper 40`s across the North Bay and San Francisco Peninsula with low/mid 50`s elsewhere. Friday will be slightly warmer in response to increased sunshine, northerly winds, and weak ridging aloft. Coastal/bayshore areas will remain cool but the interior will see more upper 80`s to low 90`s. && .LONG TERM... (Friday night through Wednesday) Issued at 247 AM PDT Thu Jun 13 2024 Heading into the weekend will be relatively quiet as temps cool a bit again down to around seasonal normals. The real story will be later in the weekend and into early next week. A deep upper low currently up in the Gulf of Alaska becomes dislodged and moves into the Pacific Northwest, kicking off another deep disturbance sliding into the West Coast/Great Basin. Well advertised by ensemble cluster analysis, there is high confidence in this pattern change taking place Sunday into Tuesday. Placement of the upper level trough axis is key when determining where the strongest winds will be and their direction. There is higher confidence that the strongest winds will remain over the waters and near coastal areas, including more inland coastal gaps such as the Petaluma Gap, San Bruno Gap, and other NW-SE oriented valleys. While we aren`t expecting any widespread offshore winds as of this forecast, the positioning of the trough will ultimately be the deciding factor, so stay tuned to future updates as confidence gradually increases. With grasses and fine fuels drying out rapidly, it looks like the Sunday-Monday timeframe is one to watch when it comes to elevated fire danger, particularly in the North Bay where fine fuels are drier than elsewhere around the Bay Area and Central Coast. For now, moisture recovery looks decent going into the weekend as winds should remain onshore, but we are keeping a close eye on the positioning of the trough and will update messaging accordingly. && .AVIATION... (18Z TAFS) Issued at 1113 AM PDT Thu Jun 13 2024 Stratus coverage continues over MRY and SNS while satellite shows stratus coverage dissipating over STS, APC, and OAK. The marine layer is expected to compress tonight with less widespread stratus than last night. Current thinking is that stratus will generally stick closer to the coast and SF bay. Low confidence that stratus will reach STS and APC but models indicate some lower level clouds may be possible. Forecast vertical wind profiles show RH values generally 50 to 60 percent so leaning towards the side that any clouds that do develop will be on the FEW to SCT side. Light to moderate west to northwesterly winds continue through the afternoon with gustier conditions returning through the afternoon into the evening. Light west to southwesterly winds return overnight for most sites before moderate winds return after the end of this TAF period. Vicinity of SFO...Moderate west to west-northwest winds continue through the afternoon before lighter westerly winds return overnight. Some uncertainty remains in wind direction but models are in higher agreement that winds stay more W to NW. Moderate confidence that MVFR conditions will return overnight with low confidence that a more compressed marine layer will push ceiling heights down into IFR territory. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Currently MVFR at MRY and SNS. Moderate confidence that ceilings at MRY will not clear as satellite shows a thicker layer of clouds over the area. Clearing at SNS is a little more uncertain with models split on if ceilings will clear this afternoon. Based on satellite trends showing stratus dissipating in the vicinity of SNS - leaning towards stratus clearing for at least a few hours this afternoon. Stratus will return early this evening at SNS with MVFR to IFR CIGs expected overnight. Winds will generally stay west to northwest with strong, gustier winds expected during the afternoon and early evening. && .MARINE... (Today through Tuesday) Issued at 1113 AM PDT Thu Jun 13 2024 A small craft advisory has been issued for the San Francisco Bay north of the Bay Bridge through the San Pablo Bay, Suisun Bay, and the West Delta for gusts up to 25 knots. Fresh to strong northwesterly winds continue over the northern waters through the end of the week with strong to near gale force gusts possible by Friday. Heading into the weekend, strong north to northwesterly winds will spread southwards over much of the coastal waters with gale-force winds increasing in likelihood. Significant wave heights up to around 12 to 15 feet in the outer waters and 10 to 13 feet in the inner waters continues into the weekend. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 9 PM PDT this evening for SF Bay N of Bay Bridge. Small Craft Advisory until 9 AM PDT Friday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory from 3 PM this afternoon to 9 AM PDT Friday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...RGass LONG TERM....Behringer AVIATION...Kennedy MARINE...Kennedy 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