425
FXUS66 KMTR 042328
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
428 PM PDT SAT APR 4 2026
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 142 PM PDT SAT APR 4 2026
- WARMER TEMPERATURES CONTINUE TODAY AND TOMORROW BEFORE A
COOLING TREND BEGINS NEXT WEEK
- BENEFICIAL RAIN CHANCES INCREASE MID TO LATE NEXT WEEK
SHORT TERM
ISSUED AT 142 PM PDT SAT APR 4 2026
(THIS EVENING THROUGH SUNDAY)
ANOTHER WARM WEEKEND REMAINS ON TRACK. INTERIOR HIGHS TODAY ARE
LARGELY IN THE LOW 80S WHILE COASTAL AREAS REMAIN IN THE 70S. THIS
SHOULD KEEP MOST SITES BELOW THEIR DAILY HIGH TEMPERATURE RECORDS
BUT SOME COASTAL SITES MAY COME CLOSE TO (OR BREAK) THEIR DAILY
RECORDS. ANOTHER WARM DAY IS EXPECTED ON SUNDAY WITH TEMPERATURES
RISING BY A FEW DEGREES COMPARED TO TODAY. THIS DOES NOT CHANGE THE
OVERALL FORECAST TOO MUCH BETWEEN SATURDAY AND SUNDAY - INLAND HIGHS
REMAIN IN THE LOW TO MID 80S WHILE COASTAL HIGHS STAY IN THE 70S.
WINDS REMAIN LIGHT AND OFFSHORE TONIGHT THROUGH TOMORROW MORNING
BEFORE SWITCHING ONSHORE AGAIN DURING THE AFTERNOON/EVENING. IN
TERMS OF THE LARGER SYNOPTIC PATTERN, A PATTERN CHANGE REMAINS ON
TRACK TO BEGIN NEXT WEEK BUT WE SEE THE FIRST INDICATIONS OF THIS
TRANSITION SUNDAY. THIS WEEKEND, UPPER LEVEL RIDGING AND HIGH
PRESSURE HAVE BEEN ABLE TO BUILD OVER CALIFORNIA, RESULTING IN
TEMPERATURES WARMING UP AND OUR MARINE LAYER BEING COMPRESSED/MIXED
OUT. SUNDAY AFTERNOON/EVENING, THE UPPER LEVEL RIDGE BEGINS TO
PROGRESS EASTWARD AS WEAK UPPER LEVEL TROUGHING BUILDS IN FROM THE
PACIFIC. THIS WILL ALLOW THE MARINE LAYER TO REDEVELOP SUNDAY NIGHT
AND BRING IN A RETURN OF STRATUS AND AN INCREASED POTENTIAL FOR
COASTAL DRIZZLE.
LONG TERM
ISSUED AT 142 PM PDT SAT APR 4 2026
(SUNDAY NIGHT THROUGH NEXT FRIDAY)
A PATTERN CHANGE IS EXPECTED NEXT WEEK WITH COOLER TEMPERATURES AND
SOME LIGHT, BENEFICIAL, RAIN MID TO LATE WEEK. AS MENTIONED IN THE
SHORT TERM, A WEAK, SHORTWAVE TROUGH ARRIVES SUNDAY INTO MONDAY
BEFORE TRANSITIONING TO MORE ZONAL FLOW (HORIZONTAL/STABLE) MONDAY
INTO MIDWEEK. THIS WILL KICK OFF A COOLING TREND WITH INLAND
TEMPERATURES DROPPING INTO THE 70S AND COASTAL TEMPERATURES INTO THE
50S TO 60S. INLAND AREAS WILL STILL BE RUNNING A FEW DEGREES ABOVE
NORMAL BUT COASTAL TEMPERATURES WILL BE FAIRLY SEASONAL AND RIGHT
AROUND AVERAGE FOR THIS TIME OF YEAR. OUT IN THE PACIFIC, A CUT-OFF
LOW IS EXPECTED TO BREAK OFF FROM A DEEP UPPER LEVEL TROUGH FURTHER
NORTH (CLOSER TO ALASKA). THIS CUT-OFF LOW LOOKS TO LINGER OVER THE
PACIFIC UNTIL WEDNESDAY AND IS PART OF THE REASON WE SEE A MORE
ZONAL PATTERN EARLY NEXT WEEK. BY WEDNESDAY, THE CUT-OFF LOW LOOKS
TO REABSORB INTO THE SYNOPTIC PATTERN AND REACHES THE WEST COAST AS
PART OF A DEEP UPPER LEVEL TROUGH. IT WILL BRING SOME MOISTURE WITH
IT (PWAT VALUES AROUND 0.8" TO 0.9") BUT THE BULK OF THE MOISTURE
WILL BE LOCATED FARTHER SOUTH. LIGHT RAIN IS EXPECTED ACROSS THE BAY
AREA AND CENTRAL COAST WEDNESDAY AND THURSDAY WITH SOME POTENTIAL
FOR SCATTERED SHOWERS FRIDAY. IT IS LOW CONFIDENCE BUT THERE IS A
NONZERO CHANCE FOR THUNDERSTORMS TO DEVELOP WITH THIS SYSTEM. IN
TERMS OF TEMPERATURE, TEMPERATURES DROP INTO THE 60S ACROSS THE
BOARD THURSDAY AND FRIDAY WITH THE WARMEST LOCATIONS REACHING THE
LOW 70S.
THE REAL QUESTION ABOUT NEXT WEEKS FORECAST COMES FROM SMALL
VARIANCES IN BOTH THE STRENGTH AND LOCATION OF THE TROUGH AS IT
MOVES ONSHORE. CLUSTER GUIDANCE PRESENTS TWO PREDOMINANT FORECASTS:
THE LOW WILL BE REABSORBED INTO THE LARGER PATTERN BUT STILL
MAINTAIN SOME ELEMENTS OF A CUT-OFF LOW AS IT LINGERS OFFSHORE MID
TO LATE WEEK, OR, IT WILL FULLY MERGE WITH THE UPPER LEVEL TROUGH
AND MOVE ONSHORE FAIRLY PROGRESSIVELY. CLUSTER GUIDANCE IS SPLIT
BETWEEN THESE TWO SCENARIOS WITH EACH PRESENTING SLIGHTLY
DIFFERENT OUTCOMES FOR THIS WEEK'S FORECAST. IF THE CUT-OFF LOW
DOES FULLY MERGE WITH THE TROUGH AND MOVES INWARDS QUICKLY, WE
COULD SEE OFFSHORE WINDS DEVELOP IN THE WAKE OF THE SYSTEM
DEPENDING ON THE ORIENTATION OF THE TROUGH. IF IT MAINTAINS
ELEMENTS OF A CUT-OFF LOW AFTER MERGING, THE POTENTIAL FOR
THUNDERSTORMS INCREASES SLIGHTLY ACROSS THE CENTRAL COAST. IF THE
CUT-OFF LOW REMAINS STATIONARY OFFSHORE (I.E. DOESN'T PROGRESS
INLAND QUICKLY) THEN WE COULD SEE A LONGER DURATION OF MOISTURE
TRANSPORT INLAND RESULTING IN ADDITIONAL LIGHT RAINFALL (LARGELY
OVER THE CENTRAL COAST). WHATEVER WAY YOU SLICE IT, THE OVERALL
PICTURE OF NEXT WEEK REMAINS THE SAME: COOLER, MORE SEASONAL
TEMPERATURES AND LIGHT, BENEFICIAL RAIN MID TO LATE WEEK. MAKE
SURE TO STAY UP TO DATE ON THE FORECAST AS NEXT WEEK APPROACHES
AND MODELS COME INTO A BETTER CONSENSUS ON THE FINER DETAILS OF
THIS SYSTEM.
AVIATION
(00Z TAFS)
ISSUED AT 428 PM PDT SAT APR 4 2026
HIGH CONFIDENCE OF VFR WITH HIGH LEVEL CLOUD COVER THROUGH THE TAF
PERIOD. WINDS REMAIN GENERALLY OFFSHORE IN THE INTERIOR REGIONS,
WITH A COASTAL BREEZE DEVELOPING AT THE IMMEDIATE COAST BEGINNING TO
SPREAD INLAND THROUGH THE AFTERNOON. WINDS DIMINISH OVERNIGHT WITH
LIGHT WINDS THROUGH EARLY SUNDAY MORNING, WHEN OFFSHORE BREEZES
DEVELOP ACROSS THE INTERIOR BEFORE A COASTAL BREEZE SETS UP IN THE
AFTERNOON. BEYOND THE TAF PERIOD, MONITORING A POTENTIAL RETURN OF
MARINE LAYER STRATUS SUNDAY NIGHT THROUGH MONDAY MORNING.
VICINITY OF SFO... HIGH CONFIDENCE OF VFR WITH HIGH LEVEL CLOUDS
THROUGH THE TAF PERIOD. BREEZY NORTHWEST WINDS WILL SET UP SHORTLY
AND CONTINUE INTO THE LATE EVENING HOURS, BECOMING LIGHT OVERNIGHT
BEFORE THE ONSHORE FLOW RESUMES SUNDAY AFTERNOON.
SFO BRIDGE APPROACH... SIMILAR TO SFO.
MONTEREY BAY TERMINALS... HIGH CONFIDENCE OF VFR WITH HIGH LEVEL
CLOUDS THROUGH THE TAF PERIOD. BREEZY SOUTHWEST WINDS PERSIST AT
MRY, WHILE THE OFFSHORE FLOW SHOULD SOON TURN NORTHWESTERLY AT SNS.
WINDS WILL DIMINISH IN THE EVENING WITH DRAINAGE FLOW OVERNIGHT. AT
SNS, THE SOUTHEAST WINDS WILL PICK UP EARLY SUNDAY MORNING BEFORE
TURNING NORTHWEST LATE IN THE AFTERNOON, WHILE AT MRY, ONSHORE FLOW
DEVELOPS IN THE AFTERNOON HOURS ON SUNDAY.
MARINE
(TONIGHT THROUGH NEXT THURSDAY)
ISSUED AT 428 PM PDT SAT APR 4 2026
LIGHT TO MODERATE NORTHERLY WINDS CONTINUE INTO NEXT WEEK WITH THE
DEVELOPMENT OF A COASTAL JET BRINGING LOCALLY FRESH TO STRONG
GUSTS ALONG THE BIG SUR COAST MIDWEEK. A LOW PRESSURE SYSTEM OVER
THE PACIFIC WILL APPROACH THE REGION BY THE MIDDLE OF NEXT WEEK
BRINGING A CHANCE OF RAIN, 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 4TH AND APRIL 5TH.
LOCATION APRIL 4TH APRIL 5TH
SANTA ROSA 88 IN 1961 90 IN 1939
KENTFIELD 85 IN 1957 88 IN 1924
SAN RAFAEL 86 IN 1960 87 IN 1957
NAPA 86 IN 1985, 1960 86 IN 1989, 1957
RICHMOND 89 IN 2011 83 IN 1989
LIVERMORE 87 IN 1959 84 IN 1989, 1916
SAN FRANCISCO 84 IN 1985 88 IN 1989
SFO AIRPORT 82 IN 1985 84 IN 1989
REDWOOD CITY 86 IN 1960 87 IN 1989
HALF MOON BAY 77 IN 2011 74 IN 2016
OAKLAND MUSEUM 85 IN 1985 85 IN 1989
SAN JOSE 87 IN 1960 89 IN 1989
SALINAS AIRPORT 86 IN 1989, 1960, 1952 95 IN 1989
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
SHORT TERM...KENNEDY
LONG TERM....KENNEDY
AVIATION...DIALH
MARINE...KENNEDY
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