514
FXUS66 KMTR 221832
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1132 AM PDT FRI MAY 22 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1200 AM PDT FRI MAY 22 2026
- DIURNALLY DRIVEN ONSHORE WINDS DURING THE AFTERNOON AND EARLY
EVENING
- WARM AND DRY WEATHER TODAY LEADS TO ELEVATED FIRE WEATHER
CONCERNS FOR THE INTERIOR BAY AREA AND CENTRAL COAST
- GRADUAL COOLING TREND BEGINS TODAY WITH SEASONAL TEMPERATURES
FOR THE UPCOMING WEEKEND AND COOLER TEMPERATURES EARLY NEXT
WEEK
UPDATE
ISSUED AT 838 AM PDT FRI MAY 22 2026
COOLED TEMPERATURES DOWN FOR THIS AFTERNOON BY A FEW TO SEVERAL
DEGREES AS WIDESPREAD STRATUS IS FORECAST TO LINGER INTO MID-TO-
LATE MORNING BEFORE RETREATING TO THE COASTLINE BY THIS
AFTERNOON. THIS IS AS A 1000-1500 FT MARINE LAYER IS IN PLACE AND
IS FORECAST TO LINGER THROUGHOUT MUCH OF THE DAY. HOWEVER, AWAY
FROM THE COAST, SUNNY CONDITIONS ARE EXPECTED THIS AFTERNOON WHICH
WILL ALLOW FOR DAYTIME HEATING.
RGASS
SHORT TERM
ISSUED AT 1200 AM PDT FRI MAY 22 2026
(TODAY AND TONIGHT)
THE STRATUS DECK HAS COMPLETELY COVERED THE COAST AND IS FLOWING
THROUGH THE PETALUMA GAP INTO THE SONOMA COUNTY VALLEYS, THROUGH THE
GOLDEN GATE INTO THE BERKELEY AREA, AND ACROSS THE MONTEREY BAY
REGION AND UP THE SALINAS VALLEY. THE BODEGA BAY PROFILER REPORTS A
MARINE LAYER AROUND 1000-1500 FT THICK, WHICH WOULD ALLOW STRATUS TO
FILL INTO THE NORTH BAY VALLEYS, THE EAST BAY WEST OF THE BERKELEY-
SAN LEANDRO HILLS, THE SANTA CLARA VALLEY, AND PERHAPS IMPACTING THE
AREA AROUND HOLLISTER OVER THE COURSE OF THE NIGHT BEFORE STRATUS
RETREATS TO THE IMMEDIATE COAST THROUGH THE POST-SUNRISE HOURS THIS
MORNING.
AN UPPER LEVEL RIDGE OVER THE NORTHERN PACIFIC THAT EXTENDS INTO THE
PACIFIC NORTHWEST IS CONTINUING TO FLATTEN UNDER THE INFLUENCE OF A
TROUGH CENTERED OVER ALASKA, ALLOWING A GRADUAL COOLING TREND TO
BEGIN TODAY. NBM MODEL OUTPUT CONTINUES TO RUN A LITTLE WARM, SO I
HAVE TAMPED DOWN TODAY'S HIGH TEMPERATURE FORECASTS. THEY'RE STILL A
SHINING EXAMPLE OF THE IMPACT OF THE BAY AREA AND CENTRAL COAST'S
FAMOUS MICROCLIMATES, WITH HIGH TEMPERATURES RANGING FROM THE MIDDLE
80S TO THE LOWER 90S IN THE INLAND VALLEYS OF THE BAY AREA AND
CENTRAL COAST, TO THE UPPER 50S TO LOWER 60S ALONG THE PACIFIC
COAST. IN BETWEEN THE TWO ARE THE NORTH BAY VALLEYS, WHERE HIGHS
RANGE FROM THE MIDDLE 70S TO LOWER 80S, THE BAYSHORE REGIONS WHERE
HIGHS RANGE IN THE 70S, TENDING WARMER THE CLOSER YOU GET TO THE
SOUTHERN EDGE OF SAN FRANCISCO BAY, AND DOWNTOWN SAN FRANCISCO
ITSELF WHERE TEMPERATURES TOP OUT AROUND THE MIDDLE 60S. BREEZY
ONSHORE WINDS WILL DEVELOP DURING THE AFTERNOON AND EVENING HOURS,
WITH GUSTS UP TO 15 TO 25 MPH THROUGH FAVORED GAPS AND PASSES.
CONTINUING HOT AND DRY CONDITIONS ACROSS THE INTERIOR REGIONS WILL
CONTRIBUTE TO ANOTHER DAY OF ELEVATED FIRE WEATHER CONCERNS. FOR
THOSE LIVING OR VISITING THOSE HOT AND DRY REGIONS, KEEP THE
FOLLOWING IN MIND:
* PROPERLY DISPOSE OF CIGARETTES AND MATCHES
* DO NOT USE A LAWN MOWER ON WEEDS OR DRY GRASS
* AVOID USING EQUIPMENT THAT CREATES SPARKS
* MAKE SURE CAMPFIRES ARE COMPLETELY PUT OUT
* MAKE SURE NO VEHICLE PARTS DRAG ON THE GROUND, INCLUDING TOWING
CHAINS
* OBEY BURN BANS & ONLY BURN WITH A PERMIT
LONG TERM
ISSUED AT 1200 AM PDT FRI MAY 22 2026
(SATURDAY THROUGH THURSDAY)
THE AFOREMENTIONED COOLING TREND CONTINUES THROUGH THE EARLY PART OF
NEXT WEEK, AND BY SATURDAY, TEMPERATURES SHOULD BE NEAR THE SEASONAL
AVERAGE WITH HIGHS IN THE MIDDLE 70S TO THE MIDDLE 80S INLAND. EARLY
NEXT WEEK, A COLD FRONT ASSOCIATED WITH A DEEP UPPER LOW IS EXPECTED
TO MAKE ITS WAY THROUGH THE REGION, AND THE ENSEMBLE MODEL RUNS ARE
STARTING TO AGREE ON A PERIOD OF COOLER TEMPERATURES AND STRONGER
ONSHORE FLOW MONDAY THROUGH WEDNESDAY. THE SLIGHT CHANCE FOR LIGHT
RAIN OR DRIZZLE CONTINUES ACROSS FAVORED COASTAL REGIONS AS THE
FRONT PASSES THROUGH, AS IS THE CONCURRENCE OF THE MODELS THAT ANY
RAINFALL THAT DEVELOPS WILL BE VERY LIGHT WITH FEW HUNDREDTHS OF AN
INCH BEING A REASONABLE HIGHER END AMOUNT FOR ANY REGION.
TOWARDS THE LATER PART OF THE WEEK, THE ENSEMBLE MODEL RUNS BEGIN TO
DIVERGE AS THE EVOLUTION OF THE UPPER LEVEL LOW AND INCOMING RIDGING
BECOMES UNCERTAIN. MOST RUNS LEAN TOWARDS A WARMING TREND FOR THAT
PERIOD, WHICH IS REFLECTED IN THE CURRENT FORECAST, WITH A
SIGNIFICANT MINORITY (AROUND 30-40% OF THE RUNS) SUGGESTING THAT
SOME FORM OF TROUGH LINGERS THROUGH THE PERIOD.
AVIATION
(18Z TAFS)
ISSUED AT 1132 AM PDT FRI MAY 22 2026
STRATUS IS ERODING FROM ALL NON-COASTAL SITES. HAF LOOKS TO KEEP
CIGS THROUGH THE DAY WHILE THE REST OF THE REGION SEES VFR BY THE
MID AFTERNOON. WIND TURN MORE MODERATE INTO THE AFTERNOON, BUT
DIRECTIONS WILL BE DETERMINED BY MORE LOCALIZED EFFECTS, RATHER THAN
AN OVERALL FLOW. WINDS REDUCE INTO THE EVENING, ALLOWING STRATUS TO
FLOW INLAND AND CAUSING IFR/MVFR CIGS TO BEGIN TO FORM AND PUSH
INLAND. LIFR CIGS AND PATCHES OF FOG WILL BE POSSIBLE IN THE NEAR
COASTAL SITES AS WELL AS IN THE NORTH BAY TERMINALS INTO SATURDAY
MORNING. CLOUD COVER LOOKS TO ERODE INTO THE LATE MORNING AND EARLY
AFTERNOON ON SATURDAY FOR ALL BUT HAF.
VICINITY OF SFO...MODERATE WEST WINDS ARRIVE INTO THE AFTERNOON AS
STRATUS CONTINUES TO RETREAT. WINDS WILL REDUCE INTO THE LATE NIGHT
AS SCATTERED CLOUDS ARRIVE. EXPECT MVFR CIGS TO FORM INTO EARLY
SATURDAY MORNING WHILE WINDS SHIFT MORE SOUTHWESTERLY. CIGS ERODE
INTO THE LATE MORNING AHEAD OF MODERATE WEST WINDS RETURNING INTO
THE AFTERNOON.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR RETURNS IN THE AFTERNOON AS MODERATE
WEST WINDS BUILD. WINDS REDUCE IN THE EARLY EVENING AS IFR CIGS MOVE
INLAND. LIFR CIGS AND POCKETS OF MIST WILL REDUCE VISIBILITIES INTO
THE NIGHT. CIGS RAISE BACK TO IFR LEVELS INTO THE MID MORNING WITH
SOME IMPROVEMENTS IN VISIBILITIES.
MARINE
(TODAY THROUGH WEDNESDAY)
ISSUED AT 838 AM PDT FRI MAY 22 2026
LIGHT TO MODERATE WINDS WILL SHIFT ACROSS THE WATERS THROUGH THE
DAY, BECOMING SOUTHWESTERLY AND LIGHT. THE SEA STATE WILL IMPROVE
HEADING INTO THE HOLIDAY WEEKEND AS NORTHWESTERLY SWELL CONTINUES
TO DECREASE.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
SHORT TERM...DIALH
LONG TERM....DIALH
AVIATION...MURDOCK
MARINE...MURDOCK
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