Technical NOAA Weather Discussion

FXUS66 KMTR 201230
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
341 AM PST Fri Feb 20 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 303 AM PST Fri Feb 20 2026

 - Cold to very cold conditions during the overnight periods
   Thursday night and Friday night

 - Unsettled weather with periods of rain and wind through the
   long term forecast period

&&

.SHORT TERM...
Issued at 303 AM PST Fri Feb 20 2026
(Today and tonight)

Isolated rain showers continue across the marine zones and Central 
Coast with the help of surface troughing. These rain showers will be 
unimpactful and are expected to wane by sunrise. It is going to be a 
cold start to the morning, so be sure to grab some extra layers on 
your way out the door! The 00Z sounding observed an 850 millibar 
temperature of -1.75 degrees Celsius which is below the tenth 
percentile (-0.5 degrees Celsius) for the date and time. While it is 
going to be cold, we are not expecting any records to be tied or 
broken. Probably of more interest (and relief) in the short term is 
that it is going to be dry as high pressure noses in from the 
Eastern Pacific Ocean. Maximum temperatures will warm to 10 degrees 
below normal today with another cold night on tap. Precautions 
should be taken to protect people, pets, and plants.

&&

.LONG TERM...
Issued at 303 AM PST Fri Feb 20 2026
(Saturday through Thursday)

Unsettled weather will return this weekend as the region gets 
skirted by a couple passing low pressure systems in the Pacific 
Northwest. Light rain showers will return to the North Bay Saturday 
morning with drizzle possible for locations farther south. More 
impactful will be the wind with southerly gusts up to 45 mph 
possible along the coast and in the higher terrain. Probabilities 
are low to moderate (less than 50% chance) and are across a small 
area, thus a Wind Advisory is not warranted at this time. The 
weekend will be your best bet to clean up any damage that occurred 
this week and prepare for next week's weather. Global ensemble 
clusters are in agreement of upper-level ridging across the 
Intermountain West and upper-level troughing off the Pacific 
Northwest Coast with heights rising at least through Monday. Another 
developing surface low pressure system off the Pacific Northwest 
will source moisture from the tropics with ECMWF and GEFS IVT 
ensemble mean peaking near 500 kg/ms by Tuesday. Southwesterly flow 
(from the tropics) will allow for efficient rainfall due to the 
fetch of moist, warm air. As a result, southwest facing terrain will 
have the highest accumulation with the help of orographic lift with 
the lee side valleys experiencing the rain shadow effect. 
Fortunately, the trend has been our friend with all of the above 
systems trending farther north between forecasts which will allow 
for a reprieve between the deluge that we have experienced the past 
week. As the forecast looks right now, the Monday into Tuesday 
system will bring widespread rainfall. Minor flooding of low-lying, 
poor drainage, and urban areas will be possible with ponding and 
slick roadways a guarantee. Mainstem river flooding is not expected 
with a low probability (less than 20%) of occurrence.

&&

.AVIATION...
(12Z TAFS)
Issued at 341 AM PST Fri Feb 20 2026

A few lingering isolated showers continue to reach the north
Central Coast this morning, otherwise VFR is forecast.

Vicinity of SFO...VFR. Light northwest to northeast wind today, 
light and variable tonight.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. Southeast winds 5 to 12 knots today, 
becoming northwest 5 to 10 knots mid to late afternoon then light
and variable to southeast 5 to 10 knots tonight.

&&

.MARINE...
(Today through Wednesday)
Issued at 303 AM PST Fri Feb 20 2026

Winds will shift to southerly and increase over the weekend, the
strongest winds across the northern waters. Rough to very rough
seas redevelop by late weekend into early next week. Rain chances
return Saturday and continue into early to mid next week.

&&

.CLIMATE...
Issued at 1047 PM PST Tue Feb 17 2026

The following are the record low temperatures at the long term sites 
for Friday, Feb 20th.

Location          Record Low

Santa Rosa        26 in 1913
Kentfield         27 in 1913
San Rafael        32 in 2018, 2006 
Napa              27 in 2018
Richmond          35 in 1990
Livermore         27 in 2018
San Francisco     38 in 1897
SFO Airport       36 in 2018
Redwood City      30 in 1933
Half Moon Bay     28 in 2018
Oakland Museum    36 in 2011
San Jose          30 in 1897
Salinas Airport   28 in 1953

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Cold Weather Advisory until 9 AM PST this morning for CAZ502-503-
     505-508-512-513-528-529.

     Extreme Cold Warning until 9 AM PST this morning for CAZ504-506-
     510-514>518.

PZ...Small Craft Advisory from 3 PM to 9 PM PST Saturday for Mry Bay.

     Small Craft Advisory from 3 AM to 3 PM PST Saturday for Pt Arena 
     to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

     Gale Warning from 3 PM to 9 PM PST Saturday for Pigeon Pt to Pt 
     Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt 
     Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt 
     Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory from 9 AM to 3 PM PST Saturday for Pigeon 
     Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt 
     Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 9 AM PST this morning for Pigeon Pt 
     to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos 
     to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory from 9 PM this evening to 3 AM PST Saturday 
     for Pt Arena to Pt Reyes 10-60 NM.

     Gale Warning from 3 AM to 9 PM PST Saturday for Pt Arena to Pt 
     Reyes 10-60 NM.

&&

$$

SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...Canepa
MARINE...Canepa

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Prepared by Boulder-Creek.com Weather at: Fri Feb 20 08:30:03 PST 2026
From the National Weather Service