Technical NOAA Weather Discussion

FXUS66 KMTR 230350
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
750 PM PST Sun Feb 22 2026

...New UPDATE...

.KEY MESSAGES...
Updated at 643 PM PST Sun Feb 22 2026

 - Dry and warmer for Monday.

 - Unsettled weather with periods of rain and wind for Monday
   night through Wednesday.

 - Warming and drying trend kicks off Thursday with the return of
   above normal temperatures.

&&

.UPDATE...
Issued at 643 PM PST Sun Feb 22 2026

Water vapor imagery shows a beautiful and complex weather pattern
over the Eastern Pacific this evening, with two storm force lows 
near 49.3 North / 135.2 West and 38.1 North / 144.5 West, 
respectively. Meanwhile, a transitory ridge of high pressure is 
building into Northern California, ahead of another developing low
near 27.8 North / 142.3 West.

Most areas today saw warmer temperatures in response to the 
building ridge and clear skies, and in fact are still trending up 
4 to 8 degrees warmer at this hour than this time last night. 
However, the North Bay remain under the influence of the moisture
plume, just enough to keep light warm air advection rain going 
across a good portion of Sonoma County. The coastal mountains of 
Sonoma County have seen the brunt of the rainfall, with 24 hour 
totals ranging between 0.60 and 1.21 inches and with Venado being
the top performer with 1.21 inches. Some of this rain did spread into
Santa Rosa as well, with the airport reporting 0.09 inches. 
Current radar also continues to show some light returns, with 
hourly rainfall rains of just a few hundredths at this time. As 
the moisture plume shift north tonight, expect these light showers
to taper off, with drier conditions developing. These drier 
conditions will prevail through most of Monday, before the rain 
returns tomorrow evening.

The main story for tomorrow though will be with the warmer
conditions across the region. In fact, 850 mb temperatures 
increase between 3 and 6 degrees across the Bay Area and Central 
Coast, and despite the increasing high cloud cover, and this 
increase should translate to the surface as well. Therefore, 
expect a pretty mild February day out there, with most locations 
seeing day time highs in the mid 60s to lower 70s. Coastal areas
will be the coolest in the lower to mid 60s. Meanwhile, the warmest
temperatures will be in the Salinas Valley and up into South Bay.

As the moisture plume re-establishes itself across the North Bay
Monday evening, light warm advection rain will redevelop. Expect
rain and gusty winds to develop across the region, spreading from
north to south Monday night and into Tuesday. Rain will linger 
across the region through Wednesday. At this point in time, it 
really looks like more beneficial rain for the region. North Bay 
will see the brunt of the rainfall, with between 0.5 and 1.5 
inches possible, with upwards over 2.5 inches in the coastal 
range. Across the Bay Area proper, expect amounts to be between 
0.25 and 0.66 inches. As you come even farther south to the 
Monterey Bay, a quarter inch or less is possible. Palmer

&&

.SHORT TERM...
Issued at 122 PM PST Sun Feb 22 2026
(This evening through Monday)

Not much change from the prior forecast, as the first round of rain 
showers traverse cross the North Bay. Rainfall amounts so far, as of 
12:30pm range from 0.0-0.17" for the valleys of Sonoma County and 
between 0.15-0.55" for the mountains with the higher amounts being 
found across the coastal side. Showers will linger through at least 
the evening hours, before lifting north into Eureka's service area 
overnight hours. Showers may skirt by the North Bay on Monday, but 
the more likely scenario is that rain holds off until late Monday 
evening or into the overnight hours. That means much of the region 
will be left with partly to mostly cloudy skies and temperatures in 
the 60s for most of the region, perhaps the low 70s for the valleys 
of the South Bay and interior Central Coast. 

&&

.LONG TERM...
Issued at 122 PM PST Sun Feb 22 2026
(Monday night through next Saturday)

The bulk of the rain will arrive on Tuesday, as a surface low sets 
up and taps into moisture from the southwest/tropics. This will 
bring periods of rain and gusty winds on Tuesday, with chances for 
rain dwindling late Tuesday night into Wednesday morning. PWATs 
across the region look to be between 1.2-1.4", which combined with 
orographic lift may lead to some heavier bands of rain and nuisance 
flooding across the North Bay or San Francisco Peninsula and into 
the Santa Cruz Mountains. Valleys may be rainshadow a bit in these 
regions, with rainfall amounts decreasing as you move south and into 
the Central Coast. In terms of thunderstorm chances, they look to be 
null as CAPE is either extremely low or zero depending on the model, 
and lapse rates are stable. 

As we begin to dry out on Wednesday, upper level ridging builds in 
from the south and will take hold of the forecast. A warming and 
drying trend begins on Thursday and continues into the weekend. 
Ensembles show ridging holding, but a low developing in the Eastern 
Pacific, perhaps trying skirt over or push it eastward by the 
beginning of March. PoP chances are low, but still reflect that non 
zero, more like 10-20% chance of rain. The CPC outlook for this 
period favors the drier scenario with leaning below normal (33-50%) 
chances for rain and likely above normal (60-80%) chances for above 
normal temperatures. 

&&

.AVIATION...
(00Z TAFS)
Issued at 352 PM PST Sun Feb 22 2026

It's VFR with exception of low clouds /MVFR-IFR/ and light rain
across Sonoma County. Forecast is near persistence tonight with a
drying trend returning to Sonoma County Monday then rain redevelops
over the North Bay and spreads southward Monday night and Tuesday. 

Vicinity of SFO...VFR. Southwest wind 12 knots becoming light
southeasterly to easterly tonight and Monday. Light southwest 
wind redevelops Monday evening with vicinity showers.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. Onshore winds 10 knots becoming 
southeasterly 5 to 10 knots tonight and Monday morning. Winds 
shifting to onshore 5 to 10 knots Monday afternoon.

&&

.MARINE...
(Tonight through next Friday)
Issued at 342 PM PST Sun Feb 22 2026

Southerly winds and seas diminish across the coastal waters except
across the far northwestern waters. Rain chances continue across
the northern waters then spread farther south Monday night through
Tuesday night. Winds and seas increase Tuesday then ease by
Wednesday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PST this evening for Pt Arena to 
     Pt Reyes 0-10 nm.

     Small Craft Advisory until 3 AM PST Tuesday for Pt Arena to Pt 
     Reyes 10-60 NM.

&&

$$

SHORT TERM...KR
LONG TERM....KR
AVIATION...Canepa
MARINE...Canepa

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Prepared by Boulder-Creek.com Weather at: Sun Feb 22 20:30:03 PST 2026
From the National Weather Service