Technical NOAA Weather Discussion

FXUS66 KMTR 190455
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
855 PM PST Wed Feb 18 2026

...New UPDATE, MARINE...

.KEY MESSAGES...
Updated at 422 PM PST Wed Feb 18 2026

 - High elevation snow continues early Thursday morning with the
   highest snow accumulations over the Central Coast

 - Strong, gusty winds, moderate to heavy rain, and slight 
   potential for thunderstorms expected around the time of frontal
   passage early Thursday morning

 - Below February normal cold continues with overnight lows and
   damp conditions making it feel even colder impacting people 
   without adequate shelter

 - Near record breaking cold temperatures Thursday night into
   Friday morning

 - Active weather continues with additional chances for rain into
   next week 

&&

.UPDATE...
Issued at 837 PM PST Wed Feb 18 2026

No real notable change in the near term forecast. KMUX radar
imagery remains active this evening. Cold and unstable atmosphere
remains over the region leading to scattered showers across the
region. KOAK sounding showed weak instability and lower freezing
levels near 3700 feet. As such, the showers are more convective,
but not seeing any lightning observed. However, we've had reports
of heavy rain and small hail. ADditionally, the low freezing
level is resulting in some snow falling across the higher peaks. 

Since the afternoon update another Winter Weather Adv was issued
for the Central Coast. Forecasting snow across the higher peaks 
of the Central Coast is very nuanced and a few hundred feet of 
snow level drift can make all the difference. Updated the snow 
amounts downward to adjust for the snow level drift. Thinking 
that the higher snow ration (10:1 or higher on some guidance) is 
overdone. The next system, currently upstream, will make its way 
southward tonight. The jet max up north will phase with a jet near
the Central Coast created a rather dynamic setup. See details 
below. As this happens, there appears to be a warm nose with snow 
levels drift upward for a few hours then dropping back down. That 
will definitely eat some snow totals. Regardless, a few inches 
will be possible above 4000-4500 ft and just fits in Advisory 
criteria. Additionally, the snow will fall with some robust winds 
with blizzard like conditions.

No other updates this evening.

MM


&&

.SHORT TERM...
Issued at 422 PM PST Wed Feb 18 2026
(This evening through Friday)

Scattered showers continue through this evening across the region 
before the next storm system arrives tonight. Widespread moderate to 
heavy rain will return tonight as our third system approaches. Rain 
intensity will pick up overnight with the heaviest precipitation 
expected between 3AM to 7AM Thursday morning. Frontal passage will 
occur between 4AM to 10AM (likely closer to 4AM-6AM period) with 
high resolution guidance showing a squall line moving through the 
Southern San Mateo Peninsula into the South Bay and Central Coast. 
This is supported by a strong 925 mb low level jet with a jet max 
near 70 knots (80 mph) moving into the Monterey Bay. This jet max is 
consistent across several high resolution models (NAM, RRFS, HRRR) 
and would support strong but short-lived gusts directly along the 
coastline. Highest confidence in widespread gusts between 30 to 40 
mph with locally stronger gusts between 45 to 50 mph directly along 
the coastline and across the higher elevations possible. Portions of 
the Big Sur Coastline and where terrain promotes wind funneling (low 
probability Salinas Valley, Golden Gate Gap) may see gusts in excess 
of 50 mph. Short-lived gusts in excess of 50 mph are likely as the 
squall line moves through with winds to drop after frontal passage 
occurs. Forecast soundings show low level 0-1 km wind shear between 
20 to 25 knots and 0-3 km wind shear in excess of 40 knots 
(particularly along the Big Sur Coast). High resolution guidance 
shows decent MUCAPE (100-450 J/KG) in the marine environment 
offshore of Santa Cruz down through Monterey County. The combination 
of strong low level shear and decent MUCAPE will result in a High 
Shear Low CAPE setup early tomorrow morning. Embedded rotation is 
possible within the squall line, particularly offshore over the 
marine environment, with the potential to impact coastal areas as 
the squall line moves ashore. Currently the SPC has a general 
mention of thunderstorms in effect for Thursday across our entire 
CWA. In addition, accumulating small hail is possible as the squall 
line moves through due to the cold airmass (850mb temperatures are 
below freezing across much of the CWA around the time of frontal 
passage). There is the potential for locally heavy downpours as the 
squall line moves onshore which may result in flooding particularly 
within coastal areas. Early morning commuters on the Central Coast 
be aware - this system will arrive around the time of the morning 
commute. Check the weather before you leave, allow extra time to 
reach your destination, and go slow. It would be advisable to avoid 
driving as this squall line moves ashore.

Rain chances and wind speeds diminish by late morning after frontal 
passage occurs. Widespread showers will become more scattered in 
nature (similar to today) by late morning/afternoon. High 
temperatures will not be particularly warm on Thursday with most 
locations staying in the upper 40s to low 50s. Across the higher 
elevations temperatures may not get out of the upper 30s to low 40s. 
As cloud cover dissipates late Thursday, overnight temperatures 
Thursday into Friday will drop rapidly into the upper 20s to low 30s 
across the region. A combination of Cold Weather Advisories and 
Extreme Cold Warnings will be needed Friday morning.

&&

.LONG TERM...
Issued at 422 PM PST Wed Feb 18 2026
(Friday night through next Wednesday)

Conditions briefly dry out on Friday as we get a break between 
systems but this will be short lived as another upper level trough 
and system arrives Saturday into Sunday. High temperatures on Friday 
will still be chilly in the low to mid 50s but if you need to make 
any outdoor preparations before the rain returns this is your 
chance. Rain returns Saturday with light rain spreading across the 
region during the afternoon/evening. Saturday night into Sunday will 
see the return of widespread moderate to at times heavy rain. The 
heaviest rain is expected Sunday and Monday as a possible 
atmospheric river develops. While the previous system (this week) 
originated from the Gulf of Alaska, this upcoming system has a more 
tropical moisture source with PWAT values in excess of an inch. 
While the heaviest rain is Sunday and Monday, light to at times 
moderate rain will continue through the rest of the week. From 
Saturday to next Wednesday - we are looking at an additional 4-6" 
across the North Bay Mountains, 3-5" across the Santa Cruz Mountains 
and Santa Lucia Range, and 1-3" across the lower elevations. A 
return of strong winds is expected late Saturday night into early 
next week. Temperatures will warm next week with highs in the upper 
50s to low 60s across the region starting Monday. Morning low 
temperatures rise into the upper 40s to 50s by Monday morning. This 
is an active period of weather. Make sure you have multiple ways to 
receive warnings this week and stay up to date on the weather 

&&

.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 low 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.

     Winter Weather Advisory from midnight tonight to 7 AM PST Friday 
     for CAZ517-518.

PZ...Gale Warning from 3 AM to 9 PM PST Thursday 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 Thursday for Mry Bay.

     Small Craft Advisory until 3 AM PST Thursday 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 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...Kennedy
LONG TERM....Kennedy
AVIATION...Murdock
MARINE...Murdock

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Prepared by Boulder-Creek.com Weather at: Wed Feb 18 22:30:03 PST 2026
From the National Weather Service