926
FXUS66 KMTR 231642
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
842 AM PST FRI JAN 23 2026
..NEW UPDATE, MARINE
KEY MESSAGES
UPDATED AT 401 AM PST FRI JAN 23 2026
- MORNING FOG ACROSS SOME BAY AREA VALLEYS AND AROUND MONTEREY
- GUSTY OFFSHORE WINDS ACROSS HIGHER TERRAIN OF THE NORTH BAY
SATURDAY
- POTENTIAL WEAK STORM SYSTEM IN THE MIDDLE OF THE NEXT WORK
WEEK
UPDATE
ISSUED AT 841 AM PST FRI JAN 23 2026
A DEEPER MARINE LAYER AROUND 1500 FEET IN DEPTH HAS RETURNED TO THE
REGION WHILE RESULTING IN WIDESPREAD LOW CLOUDS. MEANWHILE, TULE FOG
IS SPREADING WESTWARD RESULTING IN DENSE FOG ACROSS THE EAST BAY
VALLEYS. THESE CONDITIONS ARE FORECAST TO IMPROVE WITH CLOUDS
LIFTING AND EVENTUALLY CLEARING OUT BY MID-TO-LATE AFTERNOON, LAST
TO BE ACROSS THE CENTRAL COAST. OFFSHORE WINDS WILL INCREASE LATE
TONIGHT AND CONTINUE INTO SATURDAY IN THE HIGHER TERRAIN OVER THE
NORTH BAY AND EAST BAY. THE ONGOING FORECAST REMAINS ON TRACK WITH
NO UPDATES ANTICIPATED AT THIS TIME.
RGASS
SHORT TERM
ISSUED AT 401 AM PST FRI JAN 23 2026
(TODAY AND TONIGHT)
REDUCING PRESSURE HAS BROUGHT A STRONGER RETURN OF THE MARINE LAYER
TONIGHT. THIS ALONG WITH A REDUCTION OF HIGH CLOUDS, SOME MOISTURE
FROM THE CENTRAL VALLEY, AND A SLIGHT FEED OF MOISTURE FROM THE
SOUTH HAS ALLOWED FOR A GOOD SPREAD OF STRATUS AND DEVELOPING
POCKETS OF FOG. TEMPERATURES HAVE SLOWED THEIR COOLING AND ARE
ALMOST PLATEAUING FOR THE AREAS AFFECTED BY THE MARINE LAYER.
HIGH-RESOLUTION SHORT TERM MODELS SHOW THAT THESE CLOUDS AND POCKETS
OF FOG WILL BE SLOW TO ERODE. THE NEXT DEVELOPING RIDGE WILL BEGIN
TO PUSH WEAK NORTHERLY FLOW INTO THE NORTH BAY BY THE THE LATE
MORNING. THE SLIGHTLY DRIER AIR WILL HELP TO CLEAR THE NORTH BAY,
WHILE CLOUD COVER FARTHER TO THE SOUTH LINGERS INTO THE AFTERNOON.
HIGH TEMPERATURES WILL BE SLIGHTLY COOLER THAN PREVIOUS DAYS BECAUSE
OF THE PROLONGED CLOUD COVER, BUT ONLY BY A FEW DEGREES.
THE APPROACHING RIDGE WILL COMPRESS THE MARINE LAYER AND REDUCE THE
ADDITIONAL FEEDS OF MOISTURE TONIGHT, LEADING LESS LOW CLOUD COVER
AND FOG ACROSS THE AREA. HOWEVER THE MORE FOG-PRONED VALLEYS (SONOMA
CO, SALINAS VALLEY ECT) WILL STILL HAVE GOOD CHANCES FOR FOG
RETURNING TONIGHT.
LONG TERM
ISSUED AT 401 AM PST FRI JAN 23 2026
(SATURDAY THROUGH THURSDAY)
THE EASTERN PORTION OF THE DEVELOPING RIDGE WILL CONTINUE TO BUILD
INTO THE REGION INTO EARLY SATURDAY, CALLING FOR STRONGER NORTHERLY
TO NORTHEASTERLY (OFFSHORE) FLOW. THE CHANGE IN WINDS WILL LEAD TO
WIDESPREAD DRYING INTO SATURDAY, AND A MIXING OUT OF THE MARINE
LAYER. MORNING CLOUDS AND FOG WILL BE MUCH QUICKER TO ERODE ACROSS
THE REGION AND THAT EARLIER CLEARING ALONG WITH THE GENERALLY DRIER
AIRFLOW WILL CAUSE SLIGHTLY WARMER TEMPS FOR SATURDAY.
HIGHER ELEVATIONS LOOK TO SEE BREEZIER AND GUSTIER WINDS AS THE
OFFSHORE FLOW INCREASES INTO SATURDAY MORNING AND THROUGH THE DAY.
EXTRA ADJUSTMENTS WERE ADDED TO THE OVERNIGHT FORECAST PACKAGE TO
BETTER CAPTURE THE FLOW AND SPEED CHANGES, ESPECIALLY IN THE HIGHER
PEAKS OF THE NORTH BAY. LOCALIZED GUSTS AROUND 50 MPH WILL BE
POSSIBLE ON SOME OF THE PEAKS, BUT LUCKILY IT WON'T BE WIDESPREAD.
HUMIDITIES IN THESE ELEVATIONS WILL SUFFER FROM THESE INCREASED AND
DRIER WINDS, LEADING TO SOME FIRE WEATHER CONCERNS WITH A FEW AREAS
FALLING BELOW 20% HUMIDITY. WINDS LOOK TO REDUCE INTO THAT NIGHT,
BUT HUMIDITIES WILL STRUGGLE TO RECOVER ON THE HIGHER PEAKS. LOW
CLOUD COVER AND FOG WILL STRUGGLE TO FORM SUNDAY MORNING BECAUSE OF
THE DRY FLOW, BUT HIGH CLOUDS ENTER THE AREA INTO THAT AFTERNOON,
LEADING TO COOLER HIGH TEMPS.
THE RIDGE LOOKS TO FLATTEN INTO SUNDAY EVENING, WITH A ZONAL
JETSTREAM PATTERN TAKING ITS PLACE, AND OFFERING MORE ONSHORE FLOW.
HOWEVER THE JETSTREAM LOOKS TO SNAP BACK TO A QUICK RIDGE INTO THE
NEXT WORK WEEK. THIS MEANS TEMPERATURES WILL AND SOME BOUNCES UP AND
DOWN BY A FEW DEGREES, AND LOW CLOUD FORMATION WILL BE SPOTTY.
DESPITE THE QUICK RIDGE DEVELOPMENT, HIGH CLOUDS LOOK TO MOVE
THROUGH THE REGION AS A TROUGH DEVELOPS TO THE WEST. THE TROUGH
FORMATION IS WELL-ARGEED UPON BETWEEN THE LONGER TERM MODELS, BUT
THE TRAJECTORY IS A MATTER OF DEBATE. MORE MODELS POINT TO A COLD
FRONT, AND MAYBE A WEAK LOW PUSHING THROUGH THE AREA, BRINGING GOOD
CHANCES FOR WIDESPREAD MODERATE RAINS BY THE MID WEEK. HOWEVER, THE
GFS AND ITS ENSEMBLE MEMBERS SEEM KEEN ON THIS TROUGH GETTING PUSHED
UP AGAINST THE RIDGE AHEAD OF IT, AND PLACING ALL THE MOISTURE WELL
TO THE NORTH. THE GFS OUTPUT LOOKS A BIT LESS FIRM THAN OTHER MODELS
AND THE NATIONAL BLEND, BUT IS SOMETHING TO KEEP IN MIND AS THE
LONGER TERM MODELS UPDATE. FOR NOW, THE OFFICIAL FORECAST PLACES
RAIN CHANCES IN THE MIDDLE OF THE NEXT WORK WEEK ALONG THE INITIAL
FRONT WITH ADDITIONAL CHANCES POSSIBLE BEYOND THE FORECAST PERIOD.
AVIATION
(12Z TAFS)
ISSUED AT 416 AM PST FRI JAN 23 2026
STRATUS AND FOG /LIFR-IFR-MVFR/ WILL GRADUALLY MIX OUT TO VFR BY
LATE MORNING OR EARLY AFTERNOON. TULE FOG FROM THE CENTRAL VALLEY
MAY ALSO EXTEND INTO THE EAST BAY THIS MORNING. STRATUS AND FOG
REDEVELOP TONIGHT AND SATURDAY MORNING PER RECENT HREF OUTPUT.
VICINITY OF SFO...CURRENTLY IT'S VFR HOWEVER STRATUS /IFR/ WILL
DEVELOP DURING DAYBREAK THEN LIFT TO MVFR BY LATE MORNING. VFR-MVFR
TONIGHT AND SATURDAY MORNING. MAINLY LIGHT AND VARIABLE WIND.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...STRATUS /LIFR-IFR/ LIFTING TO MVFR BY
LATE MORNING. IFR STRATUS CEILINGS TONIGHT AND SATURDAY MORNING.
MAINLY LIGHT AND VARIABLE WINDS EXCEPT LIGHT ONSHORE WINDS IN THE
AFTERNOON.
MARINE
(TODAY THROUGH WEDNESDAY)
ISSUED AT 841 AM PST FRI JAN 23 2026
FRESH TO STRONG NORTHERLY BREEZES WILL PREVAIL TODAY WITH NEAR
GALE FORCE GUSTS IN THE NORTHWEST WATERS. ELSEWHERE, GENTLE TO
FRESH NORTHERLY WINDS PREVAIL. SEAS WILL BUILD TO 8-12 FEET
ACROSS EXPOSED WATERS TODAY THROUGH EARLY SATURDAY. CONDITIONS
WILL IMPROVE THIS WEEKEND WITH A GENTLE BREEZE AND MODERATE SEAS.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PST SATURDAY FOR PT ARENA TO PT
REYES 10-60 NM.
SHORT TERM...MURDOCK
LONG TERM....MURDOCK
AVIATION...CANEPA
MARINE...KR
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