Technical NOAA Weather Discussion

FXUS66 KMTR 192039
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
139 PM PDT Fri Jun 19 2026

...New SHORT TERM, LONG TERM, MARINE...

.KEY MESSAGES...
Updated at 112 PM PDT Thu Jun 18 2026

 - Hazardous beach conditions with increased risk of sneaker waves
   and strong rip currents continue through the extended forecast

 - Minor HeatRisk through the end of the week with below normal 
   temperatures expected this weekend

 - Temperatures warm and Moderate HeatRisk concerns return by 
   midweek across the interior

&&

.SHORT TERM...
Issued at 1248 PM PDT Fri Jun 19 2026
(This evening through Saturday)

Interesting weather setup across the region today and it's a tale
of the upper and low portions of the atmosphere. Let's first talk
about the lower and more impactful to the Bay Area and Central 
Coast. A solid marine layer, nearly 3,000 feet, this morning was 
loaded with ample low level moisture. Orographic lift and subtle
broad ascent aloft led to drizzlefest. This was well advertised
for several days and this morning was the real deal. Automated 
gages around the region picked a few hundredths over the last 12 
hours, most notably along the coast and coastal mts. As for the 
upper level portion of the atmosphere: a jet max, a weak 
shortwave/upper low, and abnormally high PWATs led to showers and 
thunderstorms north of the Bay Area. We did see a few high clouds
clip the N Bay, but better forcing and moisture was to the north.

Given the deep nature of the marine layer and persistent onshore 
flow several a few spots are struggling to see ample sunshine
this afternoon, especially along the coast and N bay. Elsewhere 
across the interior is seeing sun this afternoon. Despite the sun,
general consensus across the region shows a slight cooler trend 
across the region. One final highlight for the nearterm are the 
winds. The thermal difference from the cloudy coast and inland sun
will lead to another afternoon of gusty onshore flow. Gusts of 
20-30 mph seems plausible with local gusts up to 40 mph 
(gaps/passes).

Tonight through Saturday: Upper level trough along the West Coast
and low level onshore flow will usher the marine layer back in.
Just like this morning, coastal drizzle will be possible. Saturday
day will be very similar to Friday: morning clouds clearing back
to the coast, below average temps, and breezy to gusty onshore
flow in the afternoon.

&&

.LONG TERM...
Issued at 135 PM PDT Fri Jun 19 2026 
(Saturday night through next Thursday)

By the end of the weekend we begin to see a shift in the longwave
pattern over the West. The upper level trough finally begins to
lose its grip and is initially replaced with shortwave ridging
Sunday into Monday. Monday and beyond the large upper level ridge
currently shunted into Mexico begins to surge north. Therefore
500mb heights begin to rise and 850mb temps warm. What does all of
this mean for the Bay Area and Central Coast? The marine layer
will begin to compress and temperatures will begin to warming. The
trend will be more subtle Sunday into Monday, but therefore after
a more marked warming trend will develop. By the middle of next 
week interior locations will see some packets of Moderate 
HeatRisk with temps soaring into the 90s. As of now, the forecast 
does bring some nighttime relief limiting overall HeatRisk 
concerns. This could change between now and then.

This was noted on the previous discussion and worth noting again.
As the upper ridge builds over over the Desert SW next week it
then shifts eastward slightly. The eastward shift allows a plume 
a moisture to surge north on the western periphery of the ridge.
Longer range guidance brings the moisture north along Baja on
Tuesday and CA Wednesday/Thursday. Good way to describe this
scenario is low chance high impact. We don't have anything
officially in the forecast for thunderstorms, but we'll need to
keep an eye on it. 


&&

.AVIATION...
(18Z TAFS)
Issued at 1242 PM PDT Fri Jun 19 2026

The marine stratus will take a bit longer to clear out this morning 
with most sites maintaining MVFR ceilings until 21Z at the latest. 
Widespread VFR conditions with moderate SW to W breezes (11-15kt) 
prevail thereafter into the late afternoon. Most terminals will 
experience gusts in excess of 15-20kt through the day as the W-E 
pressure gradient strengthens. STS and OAK seem to be the only 
terminals spared from these gusty conditions. Gusts diminish and 
onshore winds ease by sunset. Staying true to June gloom, the marine 
layer will return later this evening resulting in widespread MVFR 
ceilings across the region. Coastal sites may see some drizzle 
around sunset time through midnight. Any accumulating precipitation 
is expected to remain very light, between 0.02-0.03 inches, and may 
cause a slight reduction in visibility.

Vicinity of SFO...Currently MVFR, but conditions will shift to VFR 
by 20Z today. SW moderate winds with strong gusts in excess of 22 kt 
prevail through the afternoon. As the marine layer deepens to around 
2500 feet overnight, MVFR ceilings are expected to impact the 
terminal as early as 08Z Saturday and persist through 19Z Saturday. 
Medium to high confidence in the forecast.

SFO Bridge Approach...SW wind and gusty pattern is similar to SFO. 
MVFR ceilings will develop slightly after SFO (09-10Z) and dissipate 
to SCT before SFO does (17-18Z). Will remain patchy through the late 
morning and become fully VFR by 19Z.

Vicinity of OAK and SJC...VFR paired with moderate breezes through 
the afternoon. Gusts around 18 kt increase by 01Z Saturday at SJC. 
OAK may experience gusts close to 20 kt, though there is a 20-30% 
chance of exceedance. MVFR ceilings will impact OAK first around 07Z 
Saturday followed by SJC a couple hours later (09Z Saturday). Winds 
ease overnight before increasing again Saturday morning when the 
stratus begins to scatter out of their respective areas.

Monterey Bay Terminals...The remaining stratus is beginning to 
scatter out of the area. VFR conditions expected by 20-21Z as the 
stratus layer retreats to the coastline. Moderate onshore winds are 
expected to increase through the afternoon with gusts in excess of 
20 kts. Another round of MVFR ceilings return this evening, 
impacting SNS first around 03Z and MRY by 05Z Saturday. Medium 
confidence on the timing of stratus at MRY as it may be intermittent 
at times. There also might be some light drizzle associated with the 
marine layer as it comes onshore, similar to this morning, but 
confidence is too low to include in the TAF. 

&&

.MARINE...
(Tonight through next Wednesday)
Issued at 1248 PM PDT Fri Jun 19 2026

Winds will increase this afternoon, becoming fresh to strong out
of the west into the early evening hours. Hazardous conditions for
small craft are expected across the San Francisco Bay, Suisun
Bay, San Pablo Bay and Monterey Bay. Long period southwest swell
will persist into the weekend with moderate W/SW winds across the
outer waters. Winds will briefly ease Saturday but will  increase
again across the outer northern water early Sunday into  the
beginning of next week.

&&

.BEACHES...
Issued at 1245 AM PDT Fri Jun 19 2026

Long period southerly swell at around 15 to 17 seconds will persist 
through early Sunday as energetic storms in the Southern 
Hemisphere continue to affect the California coast, especially for
south and southwest facing beaches. Hazardous beach conditions 
are advertised, specifically for moderate to steeply sloped 
beaches along the Pacific Coast of the North Bay, San Mateo, Santa
Cruz counties. A Beach Hazards Statement for Pacific Coast 
beaches continues through late Saturday night. Be sure to check 
beach conditions before you head out. Sneaker waves will run up 
the beach much farther than other waves, potentially catching 
beachgoers by surprise and resulting in people being swept into 
the water. Rip currents are strong enough to pull the strongest 
swimmers away from shore. Swim near a lifeguard if possible. Stay 
back from the beach, and away from jetties, piers, beachside 
rocks, and other infrastructure near the water. Never turn your 
back to the ocean! 

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through late Saturday night for CAZ006-
     505-509-529-530.

PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-SF 
     Bay N of Bay Bridge.

     Small Craft Advisory from 9 PM Saturday to 3 AM PDT Monday for 
     Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...Navarrete
MARINE...DH

Visit us at www.weather.gov/sanfrancisco

Follow us on Facebook, X, and YouTube at:
www.facebook.com/nwsbayarea
x.com/nwsbayarea
www.youtube.com/nwsbayarea


  
Prepared by Boulder-Creek.com Weather at: Fri Jun 19 14:30:02 PDT 2026
From the National Weather Service