778
FXUS66 KMTR 031758
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1058 AM PDT SUN MAY 3 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1004 AM PDT SUN MAY 3 2026
- COOLER TEMPERATURES THROUGH TUESDAY WITH A CHANCE FOR DRIZZLE
AND LIGHT RAIN, MAINLY ALONG THE COAST AND THE NORTH BAY
- WARMER AND DRIER CONDITIONS RETURN FOR THE MIDDLE OF THE WEEK
SHORT TERM
ISSUED AT 1004 AM PDT SUN MAY 3 2026
(THIS AFTERNOON THROUGH MONDAY)
IT'S A CLOUDY MORNING ACROSS THE BAY AREA AND CENTRAL COAST WITH THE
STRATUS DECK EXTENDING FAR INLAND, WITH A STRONG UPPER LEVEL LOW
MOVING OVER THE REGION ALLOWING FOR REMARKABLE EXPANSION OF THE
MARINE LAYER, TO THE POINT WHERE IT NO LONGER MAKES SENSE TO TALK
ABOUT A MARINE LAYER DEPTH. KMUX RADAR RETURNS ARE ALSO SHOWING
LIGHT RAIN SHOWERS AND DRIZZLE ACROSS THE SAN MATEO PENINSULA, PARTS
OF SANTA CLARA COUNTY, AND THE MONTEREY BAY REGION, WITH THE
POTENTIAL FOR ADDITIONAL DRIZZLE WHERE THE RADAR BEAM IS
OVERSHOOTING THE LOW LEVEL PROCESSES, SUCH AS THE NORTH BAY AND
SOUTHERN MONTEREY COUNTY. DRIZZLE CHANCES DIMINISH AFTER AROUND 1
PM, AND SOME BREAKS IN THE CLOUDS MAY DEVELOP ACROSS THE INLAND
REGIONS THIS AFTERNOON, BUT THIS IS A LOWER CONFIDENCE FORECAST.
HAVE DECREASED THE HIGH TEMPERATURE FORECAST ACROSS THE REGION IN
LIGHT OF THE POTENTIAL FOR CONTINUED CLOUDINESS THROUGH THE DAY.
HIGHS IN THE LOWER TO MIDDLE 60S ARE EXPECTED IN THE BAY AREA
INTERIOR VALLEYS, THE LOWER TO MIDDLE 70S IN THE SOUTHERN SALINAS
VALLEY, AND THE MIDDLE 50S TO LOWER 60S ALONG THE COAST AND BAYS.
CONDITIONS ARE BROADLY SIMILAR ON MONDAY AS THE UPPER LEVEL LOW
MOVES OVER THE STATE, WITH ADDITIONAL COOLING EXPECTED IN THE
SOUTHERN PARTS OF MONTEREY COUNTY AS HIGHS REACH THE MIDDLE TO UPPER
60S.
A BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH 11 PM THIS
EVENING DUE TO LONG PERIOD NORTHWESTERLY SWELL, AN INCREASING RISK
OF SNEAKER WAVES AND STRONG RIP CURRENTS. SEE THE BEACHES SECTION
FOR MORE INFORMATION.
LONG TERM
ISSUED AT 1004 AM PDT SUN MAY 3 2026
(MONDAY NIGHT THROUGH NEXT SATURDAY)
THE UPPER LEVEL LOW CONTINUES TO MOVE ACROSS CALIFORNIA THROUGH
TUESDAY, RESULTING IN A CONTINUATION OF THE COOL TEMPERATURES,
EXTENSIVE STRATUS DECKS, AND A SLIGHT CHANCE FOR LIGHT RAIN AND
DRIZZLE ACROSS THE REGION, BUT MAINLY AT THE COAST AND WITHIN
TOPOGRAPHICALLY FAVORED LOCATIONS. THE LATEST MODEL OUTPUT SHOWS THE
LOW DESCENDING INTO SOUTHERN CALIFORNIA, ALLOWING FOR A BAND OF
MOISTURE TO WRAP AROUND THE LOW AND BRING SOME WETTING RAINS TO THE
NORTH BAY MONDAY NIGHT INTO TUESDAY MORNING. THE CURRENT FORECAST
SHOWS RAIN TOTALS OF UP TO A QUARTER OF AN INCH IN THE INTERIOR
REGIONS OF THE NORTH BAY WITH TOTALS A FEW HUNDREDTHS OF AN INCH
CLOSER TO THE COAST AND EXTENDING INTO THE BAY AREA. OF NOTE, HIGH
RESOLUTION MODEL OUTPUT CONTINUES TO SHOW THE POSSIBILITY OF HIGHER
RAIN TOTALS, UP TO AROUND HALF AN INCH IN THE NORTH BAY, WHICH MIGHT
BE POSSIBLE IF THERE ARE SOME PARTICULARLY STRONG SHOWERS ACROSS THE
RAIN BAND. FLOODING CONCERNS REMAIN MINIMAL AND FOCUSED ON AREAS OF
EXCEPTIONALLY POOR DRAINAGE OR WHERE DRAINAGE PIPES ARE BLOCKED OR
CLOGGED.
BY WEDNESDAY, THE UPPER LEVEL LOW MOVES INTO THE GREAT BASIN AND
SOUTHERN ROCKIES WITH RIDGING BUILDING BACK BEHIND IT, LEADING TO A
WARMING AND DRYING TREND IN THE REGION WITH HIGHS RISING TO THE 70S
AND 80S INLAND. THE CPC EXTENDED OUTLOOK SHOWS THAT TEMPERATURES
ABOVE THE SEASONAL AVERAGES ARE LIKELY TO PERSIST THROUGH THE MIDDLE
OF MAY, WHILE PRECIPITATION TOTALS LEAN BELOW THE SEASONAL AVERAGE.
FOR CONTEXT, THE SEASONAL AVERAGE HIGH IN DOWNTOWN SAN FRANCISCO IS
AROUND 64 DEGREES, WHILE THE SEASONAL AVERAGE PRECIPITATION TOTAL
FOR THE MAY 10 TO 16 PERIOD, AS COVERED IN THE CPC 8-14 DAY OUTLOOK,
FALLS A SHADE UNDER TWO TENTHS OF AN INCH FOR THE SAME STATION.
AVIATION
(18Z TAFS)
ISSUED AT 1059 AM PDT SUN MAY 3 2026
UPPER LOW WEST OF SFO WILL KEEP CLOUD BASES HIGH TODAY, GENERALLY
ABOVE 3000 FEET BUT WITH ONLY PARTIAL CLEARING THIS AFTERNOON
BEFORE WIDESPREAD CLOUD COVER REFILLS OVERNIGHT. SOME ISOLATED
SHOWERS AND DRIZZLE REMAIN POSSIBLE AS WELL, ESPECIALLY FOR
COASTAL AREAS FROM HALF MOON BAY TO SALINAS/MONTEREY LATE NIGHT
AND MORNING HOURS.
VICINITY OF SFO...EXPECTING PERSISTENT CIGS FROM 3000-3500 FEET
THROUGH MONDAY WITH BEST CHANCE OF PERIODS OF SCATTERED CLOUDS
DURING THE AFTERNOON HOURS BUT NOT EXPECTED TO LAST LONG GIVEN
THE SYNOPTIC PATTERN.
SFO BRIDGE APPROACH...SIMILAR TO SFO UNDER THIS PATTERN AS THE
MARINE LAYER HAS BEEN LIFTED INTO A HIGHER BASED CLOUD DECK.
MONTEREY BAY TERMINALS...PERSISTENT CLOUD HEIGHTS AROUND 3000
FEET THIS AFTERNOON THROUGH MONDAY WITH ONLY OCCASIONAL BREAKS IN
THE CLOUDS AFTERNOON HOURS. PERIODS OF DRIZZLE POSSIBLE MONDAY
MORNING 13-17Z.
MARINE
(TODAY THROUGH FRIDAY)
ISSUED AT 438 AM PDT SUN MAY 3 2026
AN UPPER LEVEL LOW OVER THE REGION WILL KEEP PRESSURE GRADIENTS
LIGHT NEAR THE SURFACE ALLOWING FOR CONTINUED LIGHT WINDS ACROSS
THE COASTAL WATERS TODAY INTO EARLY NEXT WEEK. A LONG PERIOD SWELL
IS PASSING THROUGH THE WATERS WITH GENERALLY LIGHT SEAS. NW WIND
AND SEAS WILL BEGIN TO BUILD LATER IN THE WEEK AND INTO NEXT
WEEKEND.
BEACHES
ISSUED AT 1004 AM PDT SUN MAY 3 2026
LONG PERIOD NORTHWEST SWELL, WITH PERIODS OF 15 SECONDS OR ABOVE, IS
NOW BEING REPORTED ON THE OFFSHORE BUOYS AND HAS EITHER MADE IT TO
THE COAST, OR WILL ARRIVE IMMINENTLY. THESE LONG PERIOD SWELLS
INCREASE THE RISK OF SNEAKER WAVES AND RIP CURRENTS, PARTICULARLY
AS THE PERIOD BETWEEN SWELL IMPULSES RESULTS IN LULLS OF AROUND 20
TO 30 MINUTES BEFORE LARGER SETS OF WAVES ARRIVE. DUE TO THE
DANGERS, A BEACH HAZARDS STATEMENT FOR ALL PACIFIC COAST BEACHES
REMAINS IN EFFECT UNTIL 11 PM SUNDAY NIGHT. NEVER TURN YOUR BACK
TO THE OCEAN! DON'T BE FOOLED BY CALMER SEAS; OBSERVE THE WAVES
FOR AT LEAST 20 MINUTES BEFORE APPROACHING THE COAST.
MTR WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR CAZ006-505-509-
529-530.
PZ...NONE.
SHORT TERM...DIALH
LONG TERM....DIALH
AVIATION...RW
MARINE...RW
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