235
FXUS66 KMTR 051126
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
426 AM PDT SUN APR 5 2026
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 1238 AM PDT SUN APR 5 2026
- THE HOTTEST TEMPERATURES OF THE FORECAST FOR TODAY
- COOLING TREND BEGINS NEXT WEEK
- BENEFICIAL RAIN CHANCES INCREASE MID TO LATE NEXT WEEK
SHORT TERM
ISSUED AT 1238 AM PDT SUN APR 5 2026
(TODAY AND TONIGHT)
TEMPERATURES WARMED WELL FOR THE AFTERNOON AND EARLY EVENING IN
SPITE OF THE OVERCAST HIGH CLOUDS LEADING TO A FEW DAILY HIGH
TEMPERATURE RECORDS TYING: SALINAS AND HALF MOON BAY.
THESE WARMER CONDITIONS ARE THE RESULT OF A BUILDING RIDGE PATTERN,
WHICH WILL ALSO CALL FOR WARMER OVERNIGHT TEMPERATURES AND REDUCED
HUMIDITIES. EXPECT LOWS TO FALL TO THE UPPER 40S IN THE FAR
INTERIOR, WHILE THE REST OF THE REGION SEES THE MID TO LOWER 50S.
THE SLIGHTLY WARMER START AND REDUCED HUMIDITY COUPLED WITH THE
BUILDING RIDGE WILL ALLOW FOR SUNDAY TO SEE THE HOTTEST
TEMPERATURES IN THE FORECAST. WINDS WILL BE LIGHT OR STILL IN MOST
PLACES AS TEMPERATURES CLIMB 10 TO 15 DEGREES ABOVE AVERAGE FOR
MOST AREAS. A FEW ISOLATED INTERIOR AND HIGH ELEVATIONS LOOK TO
SEE HIGHS 20 DEGREES ABOVE AVERAGE. THE IMMEDIATE COAST WILL PEAK
IN THE UPPER 60S TO MID 70S, WHILE MOST OF THE INLAND AREAS SEE
THE 80S. THERE WILL BE SOME HOTTER SPOTS IN THE SANTA CRUZ
MOUNTAINS AND INTERIOR MONTEREY CO THAT COULD BREAK INTO THE 90S.
THE PATTERN CHANGES QUICKLY THAT NIGHT AS THE RIDGE PUSHES EAST AND
A WEAK SHORT-WAVE TROUGH OPENS OVER CALIFORNIA. THIS WILL ALLOW FOR
A FAIR INCREASE IN ONSHORE FLOW AND REDUCE PRESSURE ENOUGH TO
REFORM THE MARINE LAYER. THESE FACTORS WILL CAUSE CHANCES FOR FOG
AND LOW STRATUS TO RETURN TO THE COAST AND INTERIOR VALLEYS BY
MONDAY MORNING.
LONG TERM
ISSUED AT 1238 AM PDT SUN APR 5 2026
(MONDAY THROUGH SATURDAY)
EXPECT NOTABLY COOLER CONDITIONS FOR MONDAY FROM THE INCREASED
ONSHORE FLOW, BETTER HUMIDITY RETENTION, AND THAT REFORMED MARINE
LAYER. HIGHS, WILL STILL BE ABOVE AVERAGE BUT ONLY BY A FEW DEGREES.
EXPECT WIDESPREAD HIGHS IN THE 70S, WITH THE IMMEDIATE COAST IN THE
60S AND THE FAR INTERIOR SEEING THE LOW 80S.
TUESDAY AND WEDNESDAY CONTINUE THE COOLING TREND AS CLOUD COVER
INCREASES AHEAD OF A BUILDING TROUGH AND LOW PRESSURE APPROACH FROM
THE WEST.
THIS LOW WILL BRING RAIN CHANCES BACK TO FOR FORECAST, BUT HAS BEEN
SLOWING IT'S TIME OF ARRIVAL OVER THE LAST FEW FORECAST UPDATES.
INITIAL WARM-SECTOR DRIZZLE LOOKS TO HIT THE COAST BY MID TO LATE
WEDNESDAY MORNING, WHILE ACTUAL MEASURABLE RAIN WILL BE HOLDING OFF
UNTIL LATE THAT NIGHT AND INTO THURSDAY MORNING. THE SLOWING OF THIS
SYSTEM ALSO CALLS FOR RAIN CHANCES LASTING LONGER THAN PREVIOUS
FORECASTS. CHANCES FOR WIDESPREAD LIGHT RAIN AND DRIZZLE LAST
THROUGH FRIDAY WITH LINGERING, SPOTTIER CHANCES LASTING INTO
SATURDAY AFTERNOON.
DESPITE THE PROLONGED RAIN CHANCES, RAINFALL AMOUNTS STILL LOOK
FAIRLY LIGHT. MOST OF THE LOWER ELEVATIONS OF THE BAY AREA WILL ONLY
SEE A FEW HUNDREDTHS, THEN UP TO A TENTH FOR HIGHER ELEVATIONS IN
THE BAY AREA AND LOWER TERRAIN AROUND THE MONTEREY BAY, WHILE HIGHER
ELEVATIONS IN THE SANTA CRUZ MOUNTAINS AND BIG SUR COAST LOOK TO
PASS THAT QUARTER INCH MARK. ISOLATED PEAKS IN THE SANTA LUCIAS
COULD PASS THE HALF INCH MARK.
CONFIDENCE IN THE SPREAD OF RAINFALL AMOUNTS IS STILL SHAKY,
PARTICULARLY FRIDAY AND SATURDAY. MODELS SEEM TO BE STRUGGLING ON
THE TRACK OF THE LOW AND THE MOMENTUM LOSS. WHILE WIDESPREAD CHANCES
FOR LIGHT RAIN AND DRIZZLE COME WITH GOOD CONFIDENCE, THERE IS STILL
GOOD POTENTIAL FOR THESE RAINFALL TOTALS TO SEE SOME SHIFTING. IF
THE LOW TAKES A DIFFERENT TRACK OR STALLS OVER THE AREA IT COULD
LEAD TO FAIRLY NOTABLE CHANGES IN WHERE THE FOCUS OF THE RAINFALL
WILL BE. THAT BEING SAID, OVERALL RAINFALL ACROSS THE MODELS STILL
LOOKS FAIRLY LIGHT. EVEN IF THE LOW STALLS OVER THE CENTRAL
COAST, RAINFALL MAY ONLY INCREASE BY A FEW TENTHS ON THE HIGHEST
PEAKS ON BIG SUR.
AVIATION
(12Z TAFS)
ISSUED AT 420 AM PDT SUN APR 5 2026
LINGERING OFFSHORE FLOW (MUCH LESS THAN 24 HRS AGO) AND A DRY BL
HAS LED TO ANOTHER MORNING OF VFR CONDITIONS WITH A FEW HIGH
CLOUDS OVERHEAD. EXPECT VFR THROUGH EARLY TONIGHT. LOOKING FARTHER
WEST OVER THE OCEAN AD STRATUS DECK IS INCHING EAST. LATEST TIMING
BRINGS A COMPRESSED MARINE LAYER BACK TO THE COAST THIS EVENING
AND NOSING INLAND LATE TONIGHT. IMPACTS INITIALLY TO HAF AND MRY
00-04Z AND AFTER 09Z LOW CLOUDS INFILTRATE SF BAY.
VICINITY OF SFO...VFR THROUGH LATE TONIGHT. CIGS AROUND 1K FEET
RETURN FOR THE MONDAY AM RUSH.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR. LOW CIGS RETURN AFTER 00Z AND THEN
REMAIN TONIGHT.
MARINE
(TODAY THROUGH FRIDAY)
ISSUED AT 420 AM PDT SUN APR 5 2026
HIGH PRESSURE TO THE NORTH WILL MAINTAIN LIGHT TO MODERATE BREEZES
OVER THE COASTAL WATERS THROUGH EARLY NEXT WEEK. LOCALLY STRONGER
WINDS WILL DEVELOP NEAR THE BIG SUR COAST BY MIDWEEK. UNSETTLED
WEATHER RETURNS THE MIDDLE OF NEXT THANKS TO A LOW PRESSURE
SYSTEM OVER THE PACIFIC. THE LOW PRESSURE WILL BRING FRESH TO
STRONG GUSTS ACROSS THE NORTHERN WATERS, AND MODERATE SEAS.
CLIMATE
ISSUED AT 110 PM PDT FRI APR 3 2026
THE FOLLOWING ARE THE RECORD HIGH TEMPERATURES AT THE LONG TERM
STATIONS FOR APRIL 5TH.
LOCATION APRIL 5TH
SANTA ROSA 90 IN 1939
KENTFIELD 88 IN 1924
SAN RAFAEL 87 IN 1957
NAPA 86 IN 1989, 1957
RICHMOND 83 IN 1989
LIVERMORE 84 IN 1989, 1916
SAN FRANCISCO 88 IN 1989
SFO AIRPORT 84 IN 1989
REDWOOD CITY 87 IN 1989
HALF MOON BAY 74 IN 2016
OAKLAND MUSEUM 85 IN 1989
SAN JOSE 89 IN 1989
SALINAS AIRPORT 95 IN 1989
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
SHORT TERM...MURDOCK
LONG TERM....MURDOCK
AVIATION...MM
MARINE...MM
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