Technical NOAA Weather Discussion

FXUS66 KMTR 080434
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
934 PM PDT Mon Jul 7 2025

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1246 PM PDT Mon Jul 7 2025

 - Warmer temperatures return Wednesday through the weekend with 
   patchy Moderate Heatrisk across the Bay Area and Central Coast.

 - Localized elevated fire weather conditions Wednesday through 
   the weekend across portions of the Bay Area and Central Coast.

 - Slight risk (20-40%) of extreme heat for far interior portions
   of the Bay Area and Central Coast July 15th-17th.

&&

.SHORT TERM...
Issued at 1246 PM PDT Mon Jul 7 2025
(This evening through Tuesday)

High probability for low clouds to remain at the coast today and 
will then penetrate inland into the coastal valleys tonight. This is 
as an approximately 2,000 foot marine layer remain in place across 
the region and is expected to deepen slightly overnight and into 
Tuesday morning. As such, do expect coastal drizzle in the favored 
spots overnight into early Tuesday. 

With the cut off upper level low pressure centered just west off of 
the Bay Area/Central Coast, expecting another cooler than normal day 
for Tuesday. The interior will clear out by Tuesday afternoon with 
mostly sunny sky conditions. High temperatures on Tuesday will be 
in the mid 70s to 80s across the interior and upper 50s to 60s along 
the coastline (some 5 to 15 degrees below average). The cooler 
coastal areas is where clouds are forecast to persist though much of 
the day.

&&

.LONG TERM...
Issued at 203 AM PDT Mon Jul 7 2025
(Tuesday night through next Sunday)

Tuesday into Wednesday, the closed low offshore will start to 
weaken and shift northward before gradually moving inland along 
the Oregon/California border. At the same time, upper level 
ridging over the Four Corners Region will start to compress and 
spread into Southern California. The center of the high pressure 
will be located over Southern California, Southern Nevada, and 
Arizona where heat products are set to go into effect for those 
regions later this week. The forecast is a little more uncertain 
for the Central Coast and Bay Area. To start things off, a warming
trend is on track to begin Wednesday with most sites to see near 
seasonal temperatures as highs warm back into the 80s across most 
of the interior. While high pressure builds across Southern 
California Thursday and Friday, the upper level pattern shows a 
flatter, more zonal to slight troughing over the Bay Area. While 
we are expected temperatures to continue warming Thursday and 
Friday, the more zonal to slight troughing will help to keep 
temperatures slightly cooler than those to our south with highs in
the upper 80s to mid 90s. The hottest locations continue to be 
the southern most portions of the Interior Central Coast which is 
on the edge of the center of the high pressure over southern 
California. Temperatures across the interior Central Coast will be
in the mid 90s to low 100s Thursday and Friday. In terms of 
HeatRisk, pockets of moderate HeatRisk continue across urban in 
the Bay Area, interior North Bay Mountains, and far interior 
Central Coast. Remember to take breaks and drink plenty of water 
if participating in outdoors activities on Thursday and Friday. 
Temperatures cool slightly into the 80s to 90s over the weekend 
upper level troughing becomes slightly more distinct across 
Northern California. Temperatures across the interior Central 
Coast will remain fairly stable in the mid 90s to low 100s over 
the weekend as high pressure continues over Southern California. A
few isolated pockets of moderate HeatRisk will continue across 
urban areas and the North Bay Interior Mountains but will not be 
widespread enough to be very impactful. Winds remain light and 
onshore through this weekend with locally breezier winds across 
mountain gaps and passes (Altamont Pass, Salinas Valley). 

As mentioned in the short term, both small and large fuels are 
drying out with warmer temperatures increasing the likelihood of 
further drying Wednesday into the weekend. This does result in 
localized elevated fire weather concerns, particularly across the 
higher elevations above the marine layer, Wednesday through the 
weekend. While winds remain fairly light and onshore, small fuels 
have cured and larger fuels are drying out so extreme caution is 
needed if participating in any outdoor activities involving sparks 
or flames. Remember, most wildfires are started by human activities. 
One less spark, one less wildfire.

&&

.AVIATION...
(06Z TAFS)
Issued at 933 PM PDT Mon Jul 7 2025

IFR and MVFR CIGS are building along the coast and are filling 
around the Monterey Bay and look to fill over the terminals into the 
early evening. Winds reduce across the region into the evening and 
CIGs look to fall further and become more widespread later into the 
night, affecting the North Bay and SF Bay terminals as winds 
continue to reduce. Inland clearing begins in the mid morning with 
most TAF sites going VFR in the late morning. The exception will be 
HAF, which keeps CIGs through the TAF period. Winds look to stay 
light to moderate through the morning and increase into late Tuesday 
morning and afternoon. Expect winds to reduce into Tuesday evening 
as IFR/MVFR CIGs begin to move inland from the coast, filling over 
the SF Bay and Monterey Bay terminals, and the rest of the terminals 
later that night. 

Vicinity of SFO...VFR lasts into the late night. Light to moderate 
winds last through the night and much of the morning. Expect MVFR 
CIGs to fill over the terminal into the late night and erode into 
the late morning as moderate to breezy west winds arrive. These 
winds reduce into Tuesday evening as scattered IFR-level clouds 
enter the SF Bay which will fill over SFO later that night.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...MvFR CIGs Area building around the monterey 
Bay, filling at SNS and will fill over MRY into the evening. As 
winds reduce overnight, CIGs look to fall to IFR levels, with some 
pockets of mist and drizzle in the area. Winds become moderate into 
mid to late Tuesday morning as CIGs erode over the terminals, but 
expect cloud cover to linger over the Monterey Bay itself. Cloud 
cover beings to push inland as winds reduce into Tuesday evening 
with MVFR/IFR CIGs filling over the terminals.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 933 PM PDT Mon Jul 7 2025

Light to moderate southerly winds continue to affect the waters
along with moderate seas. Winds turn Northwest and increase into
Wednesday evening. The stronger winds will build rough seas by
Thursday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&

$$

SHORT TERM...RGass
LONG TERM....Kennedy
AVIATION...Murdock
MARINE...Murdock

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Prepared by Boulder-Creek.com Weather at: Tue Jul 8 00:30:03 PDT 2025
From the National Weather Service