786
FXUS66 KMTR 210327
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
827 PM PDT SUN JUL 20 2025
..NEW UPDATE, MARINE
KEY MESSAGES
UPDATED AT 231 PM PDT SUN JUL 20 2025
- BELOW NORMAL TEMPERATURES RETURN MONDAY AND CONTINUE THROUGH
THE END OF NEXT WEEK.
- LOCALIZED ELEVATED FIRE WEATHER THREAT FOR THE EAST BAY HILLS
SUNDAY AND MONDAY DUE TO DRY CONDITIONS AND GUSTY WINDS.
- GUSTY WINDS RETURN LATE TONIGHT AND CONTINUE THROUGH MONDAY
NIGHT ALONG THE COAST, RIDGETOPS, AND MOUNTAIN GAPS/PASSES.
UPDATE
ISSUED AT 821 PM PDT SUN JUL 20 2025
THE FORECAST REMAINS ON TRACK. HIGHER ELEVATIONS IN THE EAST BAY
ARE STARTING TO SEE WINDS AND GUST PICK UP WITH A FEW GUSTS NEAR
50 MPH SO FAR. THESE WINDS LOOK PEAK IN THE NEXT FEW HOURS AND
DECREASE INTO THE EARLY MORNING, BUT WILL BUILD AGAIN TOMORROW
NIGHT. AFTER THAT, THE FORECAST GET LESS EXCITING FOR THE REST OF
THE WORK WEEK.
-MURDOCK
SHORT TERM
ISSUED AT 231 PM PDT SUN JUL 20 2025
(THIS EVENING THROUGH MONDAY)
HIGH PRESSURE ACROSS THE REGION HAS MOSTLY BROKEN DOWN WITH UPPER
LEVEL TROUGHING TO BECOME REESTABLISHED THIS EVENING/OVERNIGHT. AS
TROUGHING BECOMES REESTABLISHED, THE MARINE LAYER WILL START TO
DEEPEN FROM APPROXIMATELY 1500 FT (OBSERVED ON THE 12Z OAK SOUNDING)
TO AROUND 2000 FT BY MIDDAY TOMORROW. THIS WILL ALLOW THE MARINE
LAYER TO PUSH FARTHER INLAND OVERNIGHT WITH STRATUS LIKELY TO MAKE
IT INTO THE BAY AREA VALLEYS. AT THE SAME TIME, HIGH TEMPERATURES
TOMORROW WILL COOL TO WELL BELOW NORMAL WITH TEMPERATURES RUNNING
ANYWHERE FROM 5 DEGREES TO 15 DEGREES COOLER THAN AVERAGE. A FEW OF
THE SITES IN THE HIGHER TERRAIN WILL BE CLOSER TO 20 DEGREES BELOW
NORMAL. THIS WILL RESULT IN TEMPERATURES LARGELY IN THE 70S TO LOW
80S ACROSS THE INTERIOR AND UPPER 50S TO LOW 60S ALONG THE
COASTLINE. THE INTERIOR CENTRAL COAST WILL SEE LOCALLY WARMER
TEMPERATURES IN THE 80S TO LOW 90S. FOR EXAMPLE, THE FORECASTED HIGH
FOR SAN JOSE ON MONDAY IS 75 DEGREES WHILE THE NORMAL HIGH IS 81
DEGREES. THIS PATTERN OF UPPER LEVEL TROUGHING AND COOLER THAN
NORMAL TEMPERATURES IS SET TO CONTINUE THROUGH THE REMAINDER OF THE
LONG TERM FORECAST.
IN ADDITION TO THE RETURN OF BELOW NORMAL TEMPERATURES, ONSHORE
WINDS ARE EXPECTED TO STRENGTHEN ALONG THE COAST, ACROSS MOUNTAIN
RIDGETOPS AND GAPS/PASSES, AND ACROSS THE SAN PABLO/SUISUN BAY AND
DELTA REGION. THIS WILL BRING GUSTS BETWEEN 30 TO 40 MPH ACROSS THE
ABOVE LISTED AREAS WITH HIGHER GUSTS BETWEEN 40 TO 50 MPH POSSIBLE
ACROSS THE EAST BAY HILLS. THE STRONGEST WINDS ARE LIKELY TO BE IN
THE VICINITY OF THE ALTAMONT PASS, AN AREA WHERE TERRAIN FUNNELING
IS COMMON, WITH PROBABILISTIC GUIDANCE SUGGESTING A 10% CHANCE OF
WINDS GUSTING ABOVE 50 MPH. THE AREA OF STRONGEST WINDS WILL
OCCASIONALLY REACH WIND ADVISORY CRITERIA, BUT, THE AREAL EXTENT AND
DURATION IN TIME OF THE WINDS IS TOO SHORT TO NECESSITATE ONE BEING
ISSUED. GUSTY WINDS CONTINUE FROM SUNDAY EVENING THROUGH LATE MONDAY
NIGHT/EARLY TUESDAY MORNING WITH STRONGEST WINDS TAKING PLACE DURING
THE LATE AFTERNOON/EVENING HOURS. SMALL FUELS (E.G. GRASSES) ARE DRY
WITHIN THE EAST BAY HILLS BUT LARGER 100 HOUR FUELS (E.G. SMALLER
TIMBER TYPE VEGETATION)REMAIN FAIRLY MOIST. THIS WILL HELP TO
MITIGATE THE RISK OF LARGER FIRES BUT IF A GRASS FIRE STARTS IN A
FAVORED WIND CORRIDOR IT WILL HAVE THE POTENTIAL TO EXPAND RAPIDLY.
AS SUCH, RESIDENTS OF OR TRAVELERS WITHIN THIS AREA SHOULD EXERCISE
CAUTION IF PARTICIPATING IN ANY OUTDOORS ACTIVITIES INVOLVING FLAMES
(E.G. BARBECUING, CAMPFIRES) AND ENSURE EQUIPMENT IS PROPERLY
SECURED (E.G. TOWING EQUIPMENT) TO PREVENT STRAY SPARKS.
LONG TERM
ISSUED AT 231 PM PDT SUN JUL 20 2025
(MONDAY NIGHT THROUGH NEXT SATURDAY)
GUSTY ONSHORE WINDS WILL CONTINUE THROUGH EARLY TUESDAY MORNING WITH
WINDS CONTINUING TO EASE THROUGHOUT THE REMAINDER OF THE DAY. EXPECT
A RETURN TO OUR TYPICAL DIURNALLY BREEZY PATTERN (GUSTS TO 20 TO 30
MPH) EACH AFTERNOON/EVENING FOR THE COASTLINE AND MOUNTAIN
GAPS/PASSES.
UPPER LEVEL TROUGHING WILL CONTINUE THROUGH THE END OF
THE FORECAST PERIOD WITH BELOW NORMAL TEMPERATURES (70S TO LOW 80S
ACROSS THE INTERIOR AND UPPER 50S TO MID 60S ALONG THE COAST). NO
SKY JULY REMAINS IN FULL SWING WITH WIDESPREAD OVERCAST SKIES,
COASTAL DRIZZLE, AND PATCHY COASTAL FOG TO CONTINUE THIS WEEK. THIS
TROUGH LOOKS TO DEVELOP A CUT-OFF LOW BY MIDWEEK THAT THEN HOVERS
JUST OFFSHORE OF THE BAY AREA. THIS WILL BRING THUNDERSTORM CHANCES
TO OUR NEIGHBORS IN FAR NORTHERN CALIFORNIA AND OREGON, HOWEVER,
THUNDERSTORMS ARE NOT EXPECTED TO DEVELOP WITHIN THE BAY AREA OR IN
THE CENTRAL COAST. ALL IN ALL, NOT TOO MANY CHANGES IN STORE FOR OUR
FORECAST THIS WEEK SO HOPEFULLY YOU HAVE BEEN ENJOYING THE MORE MILD
SUMMER WE HAVE HAD SO FAR.
AVIATION
(00Z TAFS)
ISSUED AT 428 PM PDT SUN JUL 20 2025
MVFR-IFR STRATUS FLOWS FORM THE COASTAL REGIONS INTO THE EAST BAY
AND MONTEREY BAY REGIONS. CONFIDENCE IS HIGH THAT THE PROBABILITIES
OF OAK AND MRY CLEARING OUT TODAY ARE VERY LOW, AND THE TERMINALS
MIGHT NOT SEE VFR CONDITIONS WELL INTO MONDAY MORNING. FOR INLAND
TERMINALS, VFR CONDITIONS CONTINUE THROUGH THE EVENING WITH MVFR-IFR
STRATUS ACROSS THE VALLEYS OVERNIGHT. STRATUS RETREATS BACK TO THE
IMMEDIATE COAST MONDAY MORNING. BREEZY ONSHORE WINDS CONTINUE
THROUGH THE EVENING HOURS, WITH GENERALLY LIGHT WINDS OVERNIGHT
BEFORE THE BREEZY FLOW RESUMES MONDAY AFTERNOON.
VICINITY OF SFO... A STREAM OF STRATUS LURKS JUST NORTH OF THE
TERMINAL, BUT THE TERMINAL ITSELF REMAINS VFR. STRATUS SHOULD COVER
THE TERMINAL THIS EVENING, WITH A MODERATE CONFIDENCE THAT THERE
WILL BE A PERIOD OF VFR CONDITIONS MONDAY AFTERNOON AND EVENING.
BREEZY WESTERLY FLOW WITH GUSTS UP TO 25 KNOTS CONTINUES THROUGH THE
EVENING HOURS, WITH LIGHT WINDS OVERNIGHT BEFORE THE BREEZY FLOW
RESUMES MONDAY AFTERNOON.
SFO BRIDGE APPROACH... SIMILAR TO SFO.
MONTEREY BAY TERMINALS... MVFR CEILINGS CONTINUE OVER THE REGION
THROUGH THE EVENING, DESCENDING TO IFR-LIFR OVERNIGHT. STRATUS
RETREATS TO THE IMMEDIATE COAST LATE MONDAY MORNING WITH MRY SOCKED
IN THROUGH THE END OF THE TAF PERIOD. BREEZY ONSHORE FLOW THROUGH
THE EVENING HOURS, BECOMING LIGHTER OVERNIGHT BEFORE RESUMING MONDAY
AFTERNOON.
MARINE
(TONIGHT THROUGH NEXT SATURDAY)
ISSUED AT 821 PM PDT SUN JUL 20 2025
MODERATE BREEZES TO NEAR-GALE FORCE GUSTS ARE EXPECTED TONIGHT
INTO MONDAY, RESULTING IN HAZARDOUS BOATING CONDITIONS FOR
SMALLER VESSELS IN THE NORTHERN SAN FRANCISCO AND SAN PABLO BAYS
AND ACROSS THE NORTHERN OUTER WATERS. STRONG BREEZES WILL ALSO
PERSIST INTO THE PRE- DAWN HOURS ON MONDAY ACROSS THE BIG SUR
COASTLINE. SLIGHT TO MODERATE SEAS PERSIST THROUGH THE REMAINDER
OF THE FORECAST PERIOD. WINDS EASE SOME THROUGH TUESDAY, EXCEPT
ACROSS SOUTHERN PORTIONS OF THE BIG SUR COAST, WHERE STRONG
NORTHWEST BREEZES PERSIST. OTHERWISE, REDUCED VISIBILITY SHOULD
BE ANTICIPATED DURING THE MORNING HOURS DUE TO FOG AND DRIZZLE.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 9 PM PDT MONDAY FOR SF BAY N OF BAY
BRIDGE.
SMALL CRAFT ADVISORY FROM 3 PM TO 9 PM PDT MONDAY FOR MRY BAY-
PIGEON PT TO PT PINOS 0-10 NM-PT PINOS TO PT PIEDRAS
BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT MONDAY FOR PT ARENA TO PT
REYES 0-10 NM-PT ARENA TO PT REYES 10-60 NM.
SHORT TERM...KENNEDY
LONG TERM....KENNEDY
AVIATION...DIALH
MARINE...DIALH
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