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
299 FXUS66 KMTR 240930 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 230 AM PDT Tue Sep 24 2024 ...New SYNOPSIS, SHORT TERM, LONG TERM, MARINE... .SYNOPSIS... Issued at 229 AM PDT Tue Sep 24 2024 Heat Advisory in effect for interior East Bay through this evening. Temperatures on Wednesday cool to near the seasonal averages, slightly warming by Friday. && .SHORT TERM... (Today and tonight) Issued at 229 AM PDT Tue Sep 24 2024 Another warm day in store across the region this afternoon, yet slightly cooler than yesterday. As such, a Heat Advisory remains in effect for the interior East Bay until 8 PM this evening due to widespread moderate HeatRisk with temperatures in the mid 90`s to near 100 degrees. Elsewhere, expecting temperatures to range from the low-to-upper 90`s in the region`s warmest interior spots, mid 80`s to lower 90`s around the San Francisco Bay Shoreline, and upper 60`s to mid 80`s as you get closer to the coast. Here`s a reminder about heat safety: * 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. Tonight, expecting a significant cool-down especially in the higher terrain as high pressure aloft shifts east with lows dropping into the 60`s. In the lower elevations, generally expecting temperatures in the 50`s to lower 60`s in the warmer interior valleys. Low clouds will also spread inland as the marine layer deepens to around 1,000 feet. && .LONG TERM... (Wednesday through Monday) Issued at 229 AM PDT Tue Sep 24 2024 A more robust cool-down is anticipated for Wednesday as the ridge moves farther east and troughing builds over the West Coast. Temperatures on Wednesday cool to or slightly below seasonal averages. A gradual warming trend is then expected through Friday as a zonal pattern sets up to our north and weak upper level troughs move through to our south and southwest. The CPC outlooks leans toward above average temperatures and below average precipitation through the first week in October. && .AVIATION... (06Z TAFS) Issued at 1139 PM PDT Mon Sep 23 2024 The marine layer remains compressed and varied in depth from 400 to 600 feet along the north Central Coast to sea level along the San Mateo county coastline northward to the coastal North Bay. A coastally trapped southerly wind reversal recently developed with the SMX-SFO pressure gradient varied between 1 mb and 2 mb. Satellite imagery shows coastal stratus and fog /VLIFR-IFR/ advancing northward and advancing into the northern Salinas Valley. In general forecast models are under-forecasting the SMX-SFO gradient at the present time and indicate the SMX-SFO strengthening Tuesday. A coupling to the mid- upper level low to our southwest may help speed up the southerly wind reversal pattern overnight through Tuesday. Vicinity of SFO...VFR. Light and variable wind becoming northwest 10 to 14 knots Tuesday afternoon and evening. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Coastal stratus and fog /VLIFR-IFR/ are advancing into the northern Salinas Valley while it`s VFR in the vicinity of KMRY. A coastally trapped southerly wind reversal is developing, however the light northwest wind (transporting stratus and fog) to KSNS may be briefly offset by a light southeast wind overnight. In general since meso-scale models are currently under- forecasting the SMX-SFO gradient (and SNS-SJC gradient) and forecast a strengthening in that respect Tuesday, expect a general increase in coverage of stratus and fog /VLIFR-IFR/ moving inland overnight and Tuesday morning. Diurnal mixing Tuesday will help lift conditions to MVFR-VFR with an early return of stratus ceilings first to KSNS then KMRY, typically the timing for southerly wind reversals. && .MARINE... (Today through Sunday) Issued at 229 AM PDT Tue Sep 24 2024 Mainly light northwesterly breezes continue through Wednesday, then increase with seas building in the outer waters by Thursday. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Heat Advisory until 8 PM PDT this evening for CAZ510-515. PZ...None. && $$ SHORT TERM...RGass LONG TERM....RGass AVIATION...Canepa MARINE...Canepa 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