Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KMTR 050404
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
904 PM PDT FRI SEP 4 2015

.SYNOPSIS...A WARMING TREND IS FORECAST TO BEGIN OVER THE WEEKEND
AND CONTINUE INTO NEXT WEEK AS HIGH PRESSURE BUILDS INLAND AND LOW
LEVEL WINDS TURN OFFSHORE. DRY CONDITIONS WILL CONTINUE THROUGH
NEXT WEEK.

&&

.DISCUSSION...AS OF 9:00 PM PDT FRIDAY...A DRY SHORTWAVE TROUGH
SWEPT ACROSS NORTHERN CALIFORNIA TODAY. THIS SHORTWAVE BROUGHT A
REINFORCING SHOT OF COOL AIR INTO NORTHERN AND CENTRAL CALIFORNIA
AND HELD AFTERNOON HIGHS BELOW SEASONAL NORMS ACROSS MOST OF OUR
REGION TODAY. BRISK WEST TO NORTHWEST WINDS DEVELOPED THIS
AFTERNOON AFTER TROUGH PASSAGE...PARTICULARLY NEAR THE COAST AND
IN THE HILLS. LATE AFTERNOON AND EARLY EVENING WIND GUSTS AS HIGH
AS 45 MPH WERE REPORTED AT SAN FRANCISCO AIRPORT...AT OCEAN BEACH
IN SAN FRANCISCO...AND THROUGH THE ALTAMONT PASS. WINDS HAVE BEEN
GRADUALLY DECREASING NEAR THE COAST THIS EVENING...BUT WILL REMAIN
LOCALLY STRONG AND GUSTY IN THE HILLS OVERNIGHT. WINDS IN THE
HILLS ARE ALSO FORECAST TO VEER MORE TO THE NORTH OVERNIGHT AND
INTO SATURDAY MORNING...WHICH WILL BRING A MUCH DRIER AIRMASS INTO
OUR REGION OVER THE WEEKEND. IN ADDITION...THE AIRMASS OVER OUR
REGION WILL WARM THROUGH THE WEEKEND AS THE UPPER TROUGH MOVES OFF
TO THE EAST AND UPPER LEVEL RIDGING BEGINS TO DEVELOP ACROSS THE
WEST. THESE DEVELOPMENTS WILL RESULT IN A ROBUST WARMING TREND
THROUGH THE HOLIDAY WEEKEND...WITH HIGH TEMPERATURES EXPECTED TO
BE ABOUT 5-7 DEGREES ABOVE NORMAL BY SUNDAY AND MONDAY.

THE UPPER TROUGH HAS COMPLETELY MIXED OUT THE MARINE LAYER AND IT
LOOKS UNLIKELY THAT A MARINE LAYER WILL HAVE A CHANCE TO REDEVELOP
BEFORE DRIER AIR BEGINS TO FILTER IN FROM THE NORTH. THUS...WE CAN
EXPECT MOSTLY CLEAR SKIES THROUGH THE HOLIDAY WEEKEND...EVEN AT
THE BEACHES. DAYTIME TEMPERATURES WILL WARM WELL INTO THE 70S AND
LOWER 80S AT THE COAST BY SUNDAY AND MONDAY. INLAND AREAS ARE
FORECAST TO WARM INTO THE 80S AND LOWER 90S. THE UPSHOT IS THAT
GOOD BEACH WEATHER IS EXPECTED OVER THE LABOR DAY WEEKEND.
HOWEVER...ANYONE PLANNING TO SPEND TIME AT THE BEACH OVER THE
THREE-DAY WEEKEND SHOULD BE AWARE THAT A LONG PERIOD SOUTHERLY
SWELL WILL RESULT IN HAZARDOUS CONDITIONS IN THE SURF
ZONE...PRIMARILY FROM RIP CURRENTS AND LARGE SHORE BREAK AT SOUTH
AND SOUTHWEST-FACING BEACHES. A BEACH HAZARD STATEMENT IS IN
EFFECT THROUGH MONDAY EVENING.

A BROAD UPPER RIDGE IS FORECAST TO REMAIN OVER THE WEST THROUGH
NEXT WEEK. THUS...WE CAN EXPECT CONTINUED WARM AND DRY CONDITIONS
THROUGH NEXT WEEK AND INTO THE FOLLOWING WEEKEND. THERE IS SOME
INDICATION THAT ONSHORE FLOW WILL BEGIN TO INCREASE AROUND
MIDWEEK...AND WE WILL PROBABLY SEE REDEVELOPMENT OF MARINE LAYER
CLOUDS BY THEN...ALONG WITH MODEST COOLING IN COASTAL AREAS.

&&

.AVIATION...AS OF 4:45 PM PDT FRIDAY...GUSTY WEST WINDS AT SFO ARE
THE MAIN CONCERN TODAY. UPPER LEVEL TROUGH MOVING THROUGH THE
AREA HAS INCREASED THE ONSHORE FLOW AND WINDS AT SFO HAVE BEEN
GUSTING TO 35 KT. MARINE LAYER IS MIXED OUT AND VFR CONDITIONS ARE
EXPECTED IN THE SFO BAY AREA OVERNIGHT WITH PATCHY MVFR IN THE MRY
BAY AREA.

VICINITY OF KSFO...VFR. WEST WINDS GUSTING TO 35 KT THROUGH 04Z.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...MVFR AFT 06Z POSSIBLY LATER.
CLEARING EARLY ON SATURDAY.

&&

.MARINE...AS OF 8:41 PM PDT FRIDAY...AN UPPER LEVEL TROUGH MOVED
THROUGH THE AREA TODAY AND SURFACE HIGH PRESSURE IS BUILDING IN
BEHIND THE SYSTEM. THIS WILL BRING GUSTY NORTHWEST WINDS THROUGH
SATURDAY. WINDS WILL DECREASE SUNDAY AND MONDAY OVER THE INNER
WATERS AS A THERMAL TROUGH DEVELOPS ALONG THE COAST. A LONG PERIOD
SOUTHERLY SWELL WILL MOVE INTO THE COASTAL WATERS OVER THE WEEKEND
RESULTING IN HAZARDOUS CONDITIONS ALONGSHORE.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...SCA...PT ARENA TO PT REYES 0-10 NM
             SCA...PT REYES TO PIGEON PT 0-10 NM
             SCA...PIGEON PT TO PT PINOS 0-10 NM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM
             SCA...PT ARENA TO PIGEON PT 10-60 NM
             SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM
             SCA...SF BAY UNTIL 11 PM
             SCA...MRY BAY UNTIL 11 PM

&&

$$

PUBLIC FORECAST: DYKEMA
AVIATION: W PI
MARINE: W PI


VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO

FOLLOW US ON FACEBOOK AND TWITTER AT:
WWW.FACEBOOK.COM/NWSBAYAREA
WWW.TWITTER.COM/NWSBAYAREA


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.