491
FXUS66 KMTR 210312
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
812 PM PDT WED MAY 20 2026
..NEW UPDATE
KEY MESSAGES
UPDATED AT 256 PM PDT WED MAY 20 2026
- DIURNALLY DRIVEN WINDS, WITH ONSHORE WINDS DURING THE
AFTERNOON AND EARLY EVENING.
- WARM AND DRY WEATHER THROUGH THURSDAY LEADS TO ELEVATED FIRE
WEATHER CONCERNS FOR THE INTERIOR BAY AREA AND CENTRAL COAST.
- ABOVE NORMAL TEMPERATURES CONTINUE THROUGH MIDWEEK WITH
SEASONAL TEMPERATURES RETURNING BY THE UPCOMING WEEKEND.
UPDATE
ISSUED AT 805 PM PDT WED MAY 20 2026
INTERESTING DEVELOPMENTS ALONG THE COASTAL BAY AREA THIS
AFTERNOON, WHERE AN IMPULSE OF ENERGY FROM THE PACIFIC NORTHWEST,
VISIBLE AS A BAND OF HIGHER CLOUDS DESCENDING INTO THE NORTH BAY,
AND PERHAPS A COASTAL EDDY WERE ABLE TO SCOUR OUT THE STRATUS DECK
ALONG THE COAST NORTH OF SANTA CRUZ. WILL MONITOR THE STRATUS
DEVELOPMENT OVERNIGHT AS THE DIFFERING FORCES INTERACT OVER THE
REGION. FORECAST REMAINS ON TRACK.
DIALH
SHORT TERM
ISSUED AT 256 PM PDT WED MAY 20 2026
(THIS EVENING THROUGH THURSDAY)
A DEEPER MARINE LAYER, ~750 FT IN DEPTH, AND STRATUS HAS RESULTED IN
COOLER CONDITIONS NEAR THE COAST SO FAR THIS AFTERNOON. TEMPERATURES
THERE ARE IN THE UPPER 50S TO MID 60S. HOWEVER, INLAND AREAS ARE
WELL ON THEIR WAY TO THE UPPER 80S TO LOWER 90S. BREEZY ONSHORE
WINDS ARE LIKELY TO INCREASE THIS AFTERNOON AND PEAK EARLY IN THE
EVENING WITH GUSTS UP TO 30 MPH BEFORE EASING OVERNIGHT. WITH LOW
CLOUDS HOVERING NEAR AND ALONG THE COAST, EXPECTING A GREATER
POTENTIAL FOR STRATUS TO SPREAD INLAND THROUGH THE GOLDEN GATE AND
INTO THE SALINAS VALLEY TONIGHT AND INTO THURSDAY MORNING.
FOR THURSDAY AFTERNOON, EXPECTING LITTLE CHANGE COMPARED TO TODAY
WITH MOSTLY SUNNY SKY CONDITIONS ACROSS THE INTERIOR. THE HIGHER
ELEVATIONS ABOVE 1000 FEET WILL REMAIN CRITICALLY DRY (10-20%) WITH
POOR OVERNIGHT (LESS THAN 30% IN SPOTS) HUMIDITY RECOVERIES.
LONG TERM
ISSUED AT 256 PM PDT WED MAY 20 2026
(THURSDAY NIGHT THROUGH NEXT TUESDAY)
TEMPERATURES ON FRIDAY WILL HEAVILY DEPEND ON HOW DEEP THE MARINE
LAYER BECOMES AS THE BAY AREA AND CENTRAL COAST REMAINS BETWEEN THE
HIGH PRESSURE TO THE WEST AND TROUGHING TO THE EAST. THE STRONGER
THE MARINE LAYER, THE LESS TIME THERE IS FOR DAYTIME HEATING
(ESPECIALLY WHERE THE STRATUS HANGS AROUND FOR MUCH OF THE DAY).
TEMPERATURES GRADUALLY COOL OVER THE WEEKEND AS TROUGHING DEVELOPS
TO THE NORTH.
THEN, COOLER AND POTENTIALLY UNSETTLED WEATHER RETURNS FOR EARLY
NEXT WEEK AS THE AFOREMENTIONED TROUGH DROPS SOUTHWARD ACROSS THE
WEST COAST. AS SUCH, THE 6-10 DAY TEMPERATURE OUTLOOK FROM THE CPC
INDICATES TEMPERATURES LEANING BELOW AVERAGE WITH THE SAME OUTLOOK
FOR PRECIPITATION LEANING ABOVE. AGAIN, ABOVE AVERAGE FOR THIS TIME
OF YEAR MAY BRING EITHER DRIZZLE AND/OR VERY LIGHT RAIN TO THE
REGION AS WE GO DEEPER INTO OUR "DRY SEASON". ALL THAT SAID, PLEASE
KEEP UP TO DATE WITH THE LATEST FORECAST INFORMATION OVER THE NEXT
FEW DAYS.
AVIATION
(00Z TAFS)
ISSUED AT 441 PM PDT WED MAY 20 2026
CURRENTLY VFR AT ALL TERMINALS WITH THE EXCEPTION OF IFR AT HAF.
MODERATE TO HIGH CONFIDENCE ON IFR CONDITIONS AT HAF, MRY, AND SNS
WITH VFR ELSEWHERE TONIGHT. DIURNAL WINDS WILL PREVAIL.
VICINITY OF SFO...CURRENTLY MVFR WITH GUSTY NORTHWESTERLY FLOW AND
HAZE. HIGH CONFIDENCE IN VFR AND DIURNAL WINDS PREVAILING THROUGH
THE TAF PERIOD; HOWEVER, FEW/SCT IFR CLOUDS WILL BE POSSIBLE ON THE
NORTH SIDE OF THE TERMINAL IF STRATUS SNEAKS THROUGH THE GOLDEN GATE
GAP.
SFO BRIDGE APPROACH...THE SAN MATEO BRIDGE APPROACH HAS A LOWER
PROBABILITY OF IFR CONDITIONS.
MONTEREY BAY TERMINALS...CURRENTLY VFR WITH NORTHWESTERLY FLOW AT
MRY AND MVFR WITH NORTHWESTERLY FLOW AND HAZE AT SNS. MODERATE
CONFIDENCE ON IFR CONDITIONS DEVELOPING AT THE TERMINALS TONIGHT.
VFR IS EXPECTED BY LATE MORNING WITH IFR STRATUS STICKING CLOSE TO
THE COAST DURING THE DAY.
MARINE
(TONIGHT THROUGH NEXT MONDAY)
ISSUED AT 441 PM PDT WED MAY 20 2026
HAZARDOUS CONDITIONS FOR SMALL CRAFT WILL CONTINUE THROUGH
THURSDAY FOR THE NORTHERN OUTERS DUE TO ROUGH SEAS AND STRONG
NORTHERLY BREEZES. ELSEWHERE, MODERATE NORTHWESTERLY BREEZES AND
MODERATE SEAS WILL PREVAIL. CONDITIONS IMPROVE INTO THE WEEKEND
AS SEAS AND NORTHWESTERLY BREEZES BECOME MODERATE.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT FRIDAY FOR PT ARENA TO PT
REYES 10-60 NM.
SHORT TERM...RGASS
LONG TERM....RGASS
AVIATION...SARMENT
MARINE...SARMENT
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