390
FXUS66 KMTR 230541
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
941 PM PST THU JAN 22 2026
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 213 PM PST THU JAN 22 2026
- MORNING FOG ACROSS SOME BAY AREA VALLEYS AND AROUND MONTEREY
- GUSTY OFFSHORE WINDS ACROSS HIGHER TERRAIN OF THE NORTH BAY
LATE FRIDAY INTO SATURDAY
- POTENTIAL WEAK TO MODERATE STORM SYSTEM NEXT WEEK AROUND
WEDNESDAY
UPDATE
ISSUED AT 753 PM PST THU JAN 22 2026
THE BIG FOCUS TONIGHT IS FOG. THE HIGH CLOUDS HAVE CLEARED,
ALLOWING FOR ENHANCED RADIATIONAL COOLING TONIGHT. THE SURFACE DEW
POINTS ARE ALSO IN THE MID 40S TO LOW 50S, PLENTY MOIST ENOUGH
FOR RADIATION FOG. IN ADDITION TO THE RADIATION FOG FORMING IN THE
VALLEYS, ADVECTION FOG IS POSSIBLE FROM BOTH THE MARINE LAYER TO
THE WEST AND TULE FOG TO THE EAST. WITH THIS PERFECT STORM OF
RADIATION AND ADVECTION FOG INGREDIENTS, HIGH RESOLUTION MODELS
ARE INDICATING A HIGH PROBABILITY OF FOG AND LOW CLOUDS FORMING
BELOW 1,000 FEET IN ELEVATION ACROSS THE BAY AREA AND CENTRAL
COAST, PARTICULARLY ALONG THE COAST AND IN THE VALLEYS. WE WILL
CLOSELY MONITOR THE SITUATION AND ISSUE DENSE FOG ADVISORIES AS
NEEDED.
SHORT TERM
ISSUED AT 213 PM PST THU JAN 22 2026
(THIS EVENING THROUGH FRIDAY)
THE CLOSED LOW THAT BROUGHT SHOWERS TO THE AREA LAST NIGHT AND
THIS MORNING IS SPINNING FURTHER AWAY TO THE SOUTH. AN INSIDE
TRACKING LOW PRESSURE SYSTEM (INSIDE SLIDER) WILL QUICKLY DIG INTO
NEVADA LATE FRIDAY. AS A RESULT, TEMPERATURES WILL NOT RECOVER AND
REMAIN AROUND NORMAL, SOME ISSUES WILL CONTINUE, AND NORTH TO
NORTHEAST WINDS WILL START TO DEVELOP.
FOR THE LOW CLOUDS AND FOG, COVERAGE SHOULD BE FAIRLY SIMILAR TO
THIS MORNING, WITH THE NORTH HILLS, SOUTHERN BAY AREA, AND
MONTEREY AREAS LIKELY TO SEE SOME. VISIBILITIES COULD DROP TO
BELOW 1 MILE IN SOME SPOTS.
FOR THE WINDS, SPEEDS WILL BE FAIRLY LIGHT THROUGH MID-DAY FRIDAY,
THEN NORTHERLY WINDS WILL START TO PICK UP. BY FRIDAY EVENING,
GUSTS OF 25 TO 35 MPH WILL DEVELOP MAINLY OVER THE INTERIOR
MOUNTAINS OF THE NORTH BAY AREA. THE WINDS WILL TURN NORTHEASTERLY
AND SPREAD BY EARLY SATURDAY (SEE LONG TERM SECTION).
LONG TERM
ISSUED AT 213 PM PST THU JAN 22 2026
(FRIDAY NIGHT THROUGH NEXT WEDNESDAY)
AS THE COLD AIR FROM THE INSIDER SLIDER SETTLES INTO IDAHO AND
NEVADA ON SATURDAY, THE OFFSHORE LEANING SURFACE PRESSURE
GRADIENTS WILL STRENGTHEN. THE WINDS ALOFT WILL ALSO BECOME
OFFSHORE FROM THE SURFACE THROUGH AND ABOVE 10,000 FEET, RESULTING
IN A DEEP LAYER OF 25 TO 35 KNOT FLOW. THE COMBINATION OF THIS
SURFACE PATTERN AND MODERATE UPPER LEVEL SUPPORT WILL ALLOW THE
WINDS AT THE GROUND TO SHIFT TO NORTH TO NORTHEASTERLY AND EXPAND
ON SATURDAY, THEN PERSIST INTO SUNDAY. THE WINDS WILL AFFECT MUCH
OF THE WIND PRONE AREAS, BUT BE FOCUSED OVER THE NORTHERN
MOUNTAINS AND HILLS WHERE WIND GUSTS OF 25 TO 35 MPH WILL BE
COMMON, AND ISOLATED GUSTS OF 45 MPH ARE POSSIBLE. THE AIR WILL
ALSO GET VERY DRY, BUT FIRE WEATHER CONCERNS ARE LOW DUE TO THE
STATE OF THE FUELS.
THE OFFSHORE FLOW WILL SHUT DOWN BY MONDAY AS WEAK RIDGING ALOFT
WILL BRING FAIRLY QUIET CONDITIONS INTO TUESDAY. SOME LOW CLOUDS
AND FOG WILL LIKELY FORM OVER THE COASTAL AREAS AS THE MARINE
LAYER REESTABLISHES ITSELF.
THEN BIG QUESTION MARKS START TO POP UP AFTER THAT. ABOUT HALF OF
THE ENSEMBLE PROJECTIONS SHOW A RAIN MAKING COLD FRONT MOVING
DOWN THE COAST AROUND WEDNESDAY OR THURSDAY, WITH SOME GUSTY SOUTH
WINDS. THE OTHER HALF DO NOT. IF IT DOES RAIN, THE AMOUNTS WILL
BE LIGHT AS NONE OF THE INDIVIDUAL RUNS HAVE ANYTHING OVER AN
INCH.
AVIATION
(06Z TAFS)
ISSUED AT 939 PM PST THU JAN 22 2026
FOG AND/OR LOW CEILINGS ARE EXPECTED AT ALL TERMINALS TONIGHT.
THE COMBINATION OF ENHANCED RADIATIONAL COOLING OF THE SURFACE
UNDER CLEAR SKIES, MARINE LAYER ADVECTION FROM THE WEST AND TULE
FOG ADVECTION FROM THE EAST CREATE A VERY FAVORABLE ENVIRONMENT
FOR AVIATION IMPACTS THROUGH THE MORNING HOURS. SKIES WILL CLEAR
IN THE MID TO LATE MORNING.
VICINITY OF SFO...THE MARINE LAYER IS FORMING, AND IS EXPECTED TO
ADVECT OVER THE PENINSULA WITH A DEPTH OF AROUND 1,000 FEET. THAT'S
DEEP ENOUGH TO GET OVER SAN BRUNO MOUNTAIN AND IMPACT THE TERMINAL,
BUT MAY BE TOO DEEP FOR DENSE FOG TO FORM AT THE SURFACE. THE MOST
LIKELY OUTCOME IS IMC CONDITIONS DUE TO CEILINGS, WITH POSSIBLE
VISIBILITY DROPS IF THE WIND DIES DOWN.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...CEILINGS HAVE ALREADY BEGUN TO FORM AT
MRY, WITH AN EARLY BASE OF 1,000 FEET. THESE WILL SURELY LOWER
AND EXPAND TO SNS THROUGH THE LATE NIGHT AND EARLY MORNING HOURS.
DESPITE THE MODERATE DRAINAGE FLOW AT SNS, MODELS ARE BULLISH ON
FOG IMPACTS AT THE TERMINAL.
MARINE
(TONIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 939 PM PST THU JAN 22 2026
A MODERATE NORTHERLY BREEZE WILL INCREASE TO STRONG THROUGH THE
DAY FRIDAY WITH NEAR GALE FORCE GUSTS IN THE NW WATERS. SEAS WILL
BUILD TO 8-12 FEET ACROSS EXPOSED WATERS FRIDAY 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...RK
LONG TERM....RK
AVIATION...FLYNN
MARINE...FLYNN
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