FXUS66 KMTR 190920
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
120 AM PST Thu Feb 19 2026
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 1256 AM PST Thu Feb 19 2026
- Thunderstorms capable of producing lightning, erratic/gusty
winds, locally heavy rainfall, accumulating small hail, and
waterspouts will be possible this morning with the cold frontal
passage
- Rain showers and thunderstorms will remain possible in the
post-frontal environment
- Accumulating snow is possible in the higher terrain, especially
for the Central Coast
- Cold to very cold conditions return tonight
- Hazardous beach conditions for Pacific Coast beaches through
Friday morning
&&
.SHORT TERM...
Issued at 1256 AM PST Thu Feb 19 2026
(Today and tonight)
A gale force low pressure system just outside of our marine zones
will continue to strengthen as it approaches the Pacific Coast. The
attendant cold front is expected to bring at least briefly hazardous
conditions in terms of thunderstorms and wind. The three ingredients
needed for a thunderstorm are lift, instability, and moisture.
Multiple lifting mechanisms are in place with upper-level support.
The instability can be characterized by conditionally unstable low-
level lapse rates and low CAPE. Today's 00Z sounding observed a PWAT
value of 0.52 inches (daily mean 0.59 inches) with the moisture
confined to the low and mid levels. While not necessary for
development, shear is another thing to look at for thunderstorms,
especially for severe potential. Forecast soundings have 30 knots of
0-1 km shear, 50 knots of 0-3 km shear, and 90 knots of 0-6 km
shear. This environment as a whole can be characterized as a high
shear, low CAPE environment: 500 J/kg or less of SBCAPE, 1000 J/kg
or less of MUCAPE, and 0-6 km shear of 35 knots or more. This
environment will be capable of producing thunderstorms with
lightning, locally strong to damaging gusts, accumulating small
hail, and waterspouts. Strong southerly winds will develop ahead
of the cold front and quickly veer after its passage to become
northwesterly. Gusts up to 50 mph are likely across the Pacific
Coast and in the higher terrain with 30-40 mph expected in low-
lying interior locations. If you must drive this morning:
keep your headlights on, keep your cruise control off, leave
plenty of following distance between the car in front of you, and
allow extra time to reach your destination. Post-frontal rain
showers are expected with a low potential for thunderstorms. Post-
frontal clearing will allow for widespread cold to very cold
conditions to settle in Thursday night. These conditions will be
impactful to people, pets, and plants - please take the necessary
precautions for each. Damp conditions will have it feeling colder
than the thermometer reads as well as pose the risk for black ice.
The warm front associated with the surface low is adding some
complexity to the snow forecast; nonetheless, high elevation snow
remains possible, especially for the Central Coast where
accumulation up to 10 inches is possible.
&&
.LONG TERM...
Issued at 1256 AM PST Thu Feb 19 2026
(Friday through Wednesday)
Friday will be cold and dry with temperatures well below normal.
Rain returns Saturday as a rapidly intensifying storm force low
pressure system encroaches the West Coast. Fortunately, it looks to
stay in the Pacific Northwest which will keep our region merely on
the periphery of it. Still, an increase in rainfall coverage and
intensity and wind can be expected. The parent low in the Gulf of
Alaska will persist, allowing for the entrainment of tropical
moisture in the Sunday into Monday timeframe. Minor flooding in low-
lying, poor drainage, and urban areas should be expected as a
result. There's a low probability (20% chance or less) of mainstem
river flooding; however, if the QPF forecast trends higher and/or
the heaviest rainfall sets up over a watershed, probabilities will
increase.
&&
.AVIATION...
(00Z TAFS)
Issued at 521 PM PST Wed Feb 18 2026
Spotty light to moderate showers are moving through the area, but
shower activity is expected to reduce into the night. Mostly mid-
level clouds are moving through the area, but these showers could
offer short-lived MVFR CIGs. Winds stay westerly for most of the
region into the evening but some areas look to turn more northerly
overnight as winds reduce. Shower activity increases into Thursday
morning with widespread rain and stronger winds arriving along a
front. Gusts will approach 30 kts and above for most areas along the
front and rain rates will reduce visibilities. Expect winds to turn
westerly to northwesterly in the wake of the front. Storm chances
will build in the post frontal environment and last into the
afternoon. Rain chances reduce that evening, but showers linger into
that night.
Vicinity of SFO...Shower activity continues with mostly mid-level
clouds. Winds turn southwest overnight and reduce, but become
southeasterly and breezy later into the night. The next band of
moderate to heavy rain arrives int he late night bringing strong
gusts above 30 kts form the southeast that will turn westerly as the
band moves through. Shower activity reduces behind the rain band,
but thunderstorms will be possible. Winds remain strong into the
afternoon but will reduce as showers become more scattered.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Spotty showers last through the night with
moderate winds turning southerly. The next rain band arrives into
the late night and early morning with stronger winds building ahead
of it. Gusts will peak above 30 kts and rain rates will reduce
visibilities. Winds reduce slightly behind the rain band, but shower
activity will continue through the afternoon. Chances for storms
will increase behind the rain band, especially in the bay itself and
along the Big Sur coast.
&&
.MARINE...
(Tonight through next Tuesday)
Issued at 837 PM PST Wed Feb 18 2026
Expect light showers to move through the waters with moderate to
breezy winds through the night. Winds quickly become strong in
the late night with widespread gale force gusts returning as
moderate to heavy rains move through the waters. Chances for
thunderstorms increase through the early morning on Thursday, but
these chances reduce that afternoon. Rough to very rough seas will
prevail through the week. Rain chances in general exit early
Friday, but the next system begins to arrive Saturday afternoon.
&&
.CLIMATE...
Issued at 1047 PM PST Tue Feb 17 2026
The following are the record loConfidence on the location and occurrence
of thunderstorms is loww temperatures at the long term sites for
Friday, Feb 20th.
Location Record Low
Santa Rosa 26 in 1913
Kentfield 27 in 1913
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...High Surf Advisory until 9 AM PST Friday for CAZ006-505-509-529-
530.
Cold Weather Advisory from 1 AM to 9 AM PST Friday for CAZ502-
503-505-508-512-513-528-529.
Extreme Cold Warning from 1 AM to 9 AM PST Friday for CAZ504-506-
510-514>518.
Winter Weather Advisory until 7 AM PST Friday for CAZ517-518.
PZ...Gale Warning until 9 PM PST this evening for Mry Bay-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 Arena to Pt Reyes 10-60 NM-Pt Pinos
to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm-
SF Bay N of Bay Bridge.
Small Craft Advisory until 3 AM PST early this morning for Mry
Bay-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 Arena to Pt Reyes 10-
60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to
Pigeon Pt 0-10 nm.
&&
$$
SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...Murdock
MARINE...Murdock
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Prepared by Boulder-Creek.com Weather at: Thu Feb 19 02:30:04 PST 2026
From the National Weather Service
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