201
FXUS66 KMTR 032017
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
117 PM PDT FRI APR 3 2026
..NEW CLIMATE
KEY MESSAGES
UPDATED AT 107 PM PDT FRI APR 3 2026
- MODERATE TO STRONG OFFSHORE FLOW THROUGH REMAINDER OF TODAY
- WARMER TEMPERATURES RETURN SATURDAY AND SUNDAY BEFORE A COOLING
TREND BEGINS NEXT WEEK
- BENEFICIAL RAIN CHANCES INCREASE MID TO LATE NEXT WEEK
SHORT TERM
ISSUED AT 107 PM PDT FRI APR 3 2026
(THIS EVENING THROUGH SATURDAY)
BREEZY OFFSHORE WINDS CONTINUE THROUGH EARLY TOMORROW MORNING. THE
STRONGEST WIND GUSTS HAVE LARGELY BEEN CONFINED TO THE HIGHER
ELEVATIONS OF THE NORTH BAY INTERIOR MOUNTAINS AND THE DIABLO RANGE.
THE STRONGEST GUST REPORTED SO FAR WAS 67 MPH AT THE MT. ST. HELENA
WEST STATION (ELEVATION OF 4340 FT) AT 7:30 AM THIS MORNING. AT THAT
TIME THE SFO-WMC PRESSURE GRADIENT PEAKED AT -10 MB. WINDS HAVE
SINCE COME DOWN SLIGHTLY BUT ARE LIKELY TO INCREASE AGAIN DURING THE
AFTERNOON AND EVENING HOURS. THE SFO-WMC GRADIENT HAS REGAINED
STRENGTHEN OVER THE LAST FEW HOURS (AFTER INITIALLY WEAKENING FROM
EARLY THIS MORNING) WITH THE 11AM OBSERVATION COMING IN AT -9.80 MB.
GFS GUIDANCE MOST CLOSELY RESEMBLES THE OBSERVED SFO-WMC GRADIENT
AND KEEPS OFFSHORE WINDS CONTINUING INTO SUNDAY. ANOTHER, BRIEF,
ROUND OF BREEZY WINDS IS POSSIBLE ACROSS THE HIGHER ELEVATIONS EARLY
SATURDAY MORNING BEFORE WINDS DECREASE THROUGH THE REMAINDER OF THE
DAY.
HIGH TEMPERATURES TODAY ARE SEASONABLY WARM IN THE 60S ALONG THE
COAST AND 70S ACROSS THE INTERIOR. THIS IS RUNNING ABOUT 5 TO 10
DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR AND IS THE RESULT OF
UPPER LEVEL RIDGING AND SURFACE HIGH PRESSURE BUILDING IN. THE
WARMING TREND CONTINUES INTO SATURDAY WITH HIGH TEMPERATURES IN THE
70S TO 80S EXPECTED (15-20 DEGREES ABOVE NORMAL). CURRENTLY ONLY
MINOR HEATRISK IS FORECAST TODAY AND TOMORROW THANKS TO GOOD
OVERNIGHT COOLING. LIGHT, OFFSHORE WINDS PREVAIL ON SATURDAY WHICH
WILL PLAY A ROLE IN KEEPING COASTAL AREAS WARMER THANKS TO AN EFFECT
CALLED DOWNSLOPING. DOWNSLOPING OCCURS WHEN WIND IS FORCED DOWN THE
LEEWARD SIDE OF THE MOUNTAIN WITH AN AIR PARCEL COMPRESSING (AND
WARMING) AS IT SINKS. THIS TYPE OF SETUP IS FAVORABLE FOR BRINGING
MUCH WARMER AND DRIER TEMPERATURES DIRECTLY ALONG THE COAST COMPARED
TO THE NORMALLY COOLER TEMPERATURES WE OBSERVE. FOR THE AFTERNOON
FORECAST PACKAGE, DID ADJUST HIGH TEMPERATURES UP SLIGHTLY FOR
SATURDAY AND SUNDAY GIVEN THAT THE DETERMINISTIC NBM WAS RUNNING
MUCH COOLER THAN OTHER MODELS. GIVEN THE VERY DRY ATMOSPHERE, FOG IS
NOT EXPECTED TO DEVELOP TONIGHT WITH HREF ONLY SHOWING HIGH CLOUDS
MOVING THROUGH.
LONG TERM
ISSUED AT 107 PM PDT FRI APR 3 2026
(SATURDAY NIGHT THROUGH NEXT THURSDAY)
ABOVE NORMAL TEMPERATURES CONTINUE INTO SUNDAY WITH HIGHS REMAINING
15-20 DEGREES ABOVE NORMAL. THIS KEEPS TEMPERATURES IN THE 80S
ACROSS THE INTERIOR AND 70S ALONG THE COASTLINE. THERE IS A LITTLE
MORE UNCERTAINTY WITH REGARDS TO SUNDAY'S HIGH TEMPERATURES THAN
SATURDAY'S. ON SATURDAY, THE CENTER OF THE UPPER LEVEL RIDGE IS
CENTERED MORE OVER CALIFORNIA WHILE ON SUNDAY THE RIDGE IS
PROGRESSING RAPIDLY EASTWARD. AS THE RIDGE DEPARTS, THE SFO-WMC
PRESSURE GRADIENT IS EXPECTED TO REVERSE (BECOMING POSITIVE) AND
ONSHORE FLOW RETURNS. CURRENTLY, OFFSHORE WINDS ARE LIKELY TO REMAIN
THROUGH AT LEAST SUNDAY MORNING BUT POTENTIALLY INTO EARLY SUNDAY
AFTERNOON. THE LONGER OFFSHORE WINDS STICK AROUND, THE MORE SURFACE
TEMPERATURES ARE ABLE TO WARM. THE CURRENT THINKING IS THAT
TEMPERATURES WILL PEAK EARLY TO MID AFTERNOON AND START DECREASING
AS THE SEA BREEZE/ONSHORE WINDS KICK IN. ANOTHER FACTOR IS THE
POTENTIAL FOR THE MARINE LAYER TO REDEVELOP, BRINGING A RETURN OF
COASTAL STRATUS AND FOG. THE MARINE LAYER NOW LOOKS TO RETURN
OVERNIGHT SUNDAY INTO MONDAY THAN SUNDAY AFTERNOON/EVENING. THIS
LIMITS THE IMPACT IT WOULD HAVE ON SUNDAY'S HIGH TEMPERATURES BUT
IT'S WORTHWHILE NOTING THAT THE SIGNAL IS THERE FOR THE MARINE LAYER
TO REDEVELOP HEADING INTO NEXT WEEK. THERE IS THE POTENTIAL FOR SOME
DAILY HIGH TEMPERATURE RECORDS TO BE BROKEN SATURDAY AND SUNDAY (ONE
SITE BEING HALF MOON BAY) DEPENDING ON HOW HIGH TEMPERATURES WARM.
TEMPERATURES COOL SLIGHTLY, BECOMING SEASONABLY WARM, INTO THE 70S
TO LOW 80S ACROSS THE INTERIOR MONDAY AND TUESDAY AS UPPER LEVEL
RIDGING PROGRESSES EASTWARD AND ZONAL FLOW RETURNS. THE COAST WILL
BE NOTICEABLY COOLER WITH SEASONAL HIGH TEMPERATURES IN THE 60S
EXPECTED. THE COOLING TREND CONTINUES THROUGH LATE NEXT WEEK AS AN
UPPER LEVEL TROUGH MOVES THROUGH THE WEST COAST. THIS SYSTEM WILL
BRING US OUR NEXT CHANCE OF BENEFICIAL RAIN. TOTALS ARE STILL LIGHT
WITH THE MAJORITY OF THE REGION SEEING LESS THAN A QUARTER OF AN
INCH. THE HIGHER ELEVATIONS OF THE SANTA CRUZ MOUNTAINS AND THE
SANTA LUCIA RANGE MAY SEE BETWEEN 0.25 TO 0.5" OF RAIN. THERE IS
ALSO THE POTENTIAL FOR THIS SYSTEM TO BRING LOCALLY GUSTIER ONSHORE
AVIATION
(18Z TAFS)
ISSUED AT 1104 AM PDT FRI APR 3 2026
DRY AIR AND OFFSHORE WINDS SUPPORT VFR FOR THE 18Z TAFS.
VICINITY OF SFO...VFR. NORTHEAST WIND NEAR 5 KNOTS BECOMING
NORTHWEST 10 TO 15 KNOTS IN THE AFTERNOON AND EARLY EVENING. WIND
SHIFTING TO LIGHT SOUTHEAST TONIGHT AND CONTINUING SATURDAY
BEFORE SHIFTING TO NORTHWEST NEAR 10 KNOTS LATE SATURDAY
AFTERNOON.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR. EAST TO SOUTHEAST WINDS 5 TO 15
KNOTS SHIFTING TO NORTHWESTERLY 10 KNOTS IN THE AFTERNOON AND
EARLY EVENING. WINDS SHIFTING TO EAST TO SOUTHEAST 5 TO 15 KNOTS
TONIGHT AND SATURDAY MORNING.
MARINE
(TODAY THROUGH WEDNESDAY)
ISSUED AT 1052 AM PDT FRI APR 3 2026
FRESH TO STRONG NORTHERLY BREEZES WILL PERSIST OVER THE NORTHERN
OUTER WATERS THROUGH TODAY. WINDS AND SEAS WILL ABATE TONIGHT AND
THROUGH THE WEEKEND. LIGHT TO MODERATE NORTHERLY BREEZES PREVAIL
THIS WEEKEND AND INTO NEXT WEEK.
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.
LOCATION APRIL 4TH
SANTA ROSA 88 IN 1961
KENTFIELD 85 IN 1957
SAN RAFAEL 86 IN 1960
NAPA 86 IN 1985, 1960
RICHMOND 89 IN 2011
LIVERMORE 87 IN 1959
SAN FRANCISCO 84 IN 1985
SFO AIRPORT 82 IN 1985
REDWOOD CITY 86 IN 1960
HALF MOON BAY 77 IN 2011
OAKLAND MUSEUM 85 IN 1985
SAN JOSE 87 IN 1960
SALINAS AIRPORT 86 IN 1989, 1960, 1952
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT SATURDAY FOR PT ARENA TO PT
REYES 10-60 NM.
SHORT TERM...KENNEDY
LONG TERM....KENNEDY
AVIATION...CANEPA
MARINE...CANEPA
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, X, AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSBAYAREA
X.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page