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

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 252253
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
253 PM PST WED FEB 25 2015

...SHOWERS RETURN FOR FRIDAY AND SATURDAY...

.SYNOPSIS...DRY AND MILD WEATHER CONDITIONS WILL CONTINUE
THROUGH TOMORROW  AS HIGH PRESSURE REMAINS OFF OF THE WEST COAST.
A STORM SYSTEM WILL THEN BRING SHOWERS AND COOLER TEMPERATURES TO
THE REGION FRIDAY INTO SATURDAY. ANOTHER ROUND OF SHOWERS IS
EXPECTED STARTING NEXT MONDAY.

&&

.DISCUSSION...AS OF 3:00 PM PST WEDNESDAY...QUIET WEATHER ACROSS
OUR AREA TODAY WITH GENERALLY SUNNY SKIES THANKS TO A STRONG
NORTHERLY SURFACE GRADIENT (NOW OVER 6 MB) WHILE NEARLY NEUTRAL
CONDITIONS ARE FOUND WEST TO EAST. TEMPERATURES ARE NOW RUNNING A
FEW DEGREES COOLER THAN YESTERDAY WHICH GOES ALONG WELL WITH THE
OAKLAND SOUNDING THIS MORNING THAT INDICATED UP TO 3C OF COOLING
TO THE 950 MB LEVEL. GUIDANCE SHOWS CLOUDS MOVING BACK TO THE BAYS
AND ADJACENT VALLEYS OVERNIGHT TONIGHT ALTHOUGH WITH THE NORTHERLY
GRADIENT EXPECTED TO REMAIN MUCH STRONGER THAN THE WESTERLY ONE
THIS SEEMS SUSPICIOUS AT BEST. THEREFORE CLOUDS WERE REDUCED IN
THE GRIDS THROUGH THE OVERNIGHT HOURS. IF ANY FOG FORMS IT IS
EXPECTED TO BE CONFINED TO NORTH SF BAY PLUS NORTH BAY VALLEYS.
LOWS WILL MOSTLY BE IN THE UPPER 30S TO UPPER 40S. ALSO WORTH
NOTING THAT THE MONTEREY BAY BUOY IS BACK TO 59 DEGREES -- WELL
ABOVE ITS NORMAL 52 TO 54 RANGE WE WOULD EXPECT THIS TIME OF YEAR.
TOMORROW SHOULD BE SIMILAR TO TODAY WITH A FEW DEGREES OF WARMING
FORECAST. LOOK FOR MID 60S TO LOWER 70S IN MOST LOCATIONS.

BY FRIDAY A STORM SYSTEM OVER THE PACNW THAT IS CURRENTLY NEAR THE
GULF OF ALASKA WILL DIVE SOUTHWARD TOWARD OUR AREA. WINDS WILL
PICK UP THROUGH THE DAY AS AN ASSOCIATED COLD FRONT ADVANCES NORTH
TO SOUTH THROUGH OUR AREA. SCATTERED SHOWERS WILL MOVE INTO THE
NORTH BAY BY FRIDAY MORNING OR AFTERNOON AND THROUGH THE REST OF
OUR AREA BY FRIDAY EVENING OR NIGHT. MOISTURE WILL BE FAIRLY
LIMITED WITH THE SYSTEM ALTHOUGH PLENTY OF COLD AIR ADVECTION PLUS
HAVING THE UPPER LOW MOVE OVERHEAD ON SATURDAY WILL PRODUCE A
CLASSIC CONVECTIVE SETUP FOR THE SF/MONTEREY BAY REGION. VARIOUS
CONVECTIVE PARAMETERS (LI...CAPE...MUCAPE) ARE ALL FOCUSING ON
SATURDAY BEING THE BEST CHANCE FOR SMALL HAIL ALONG WITH A FEW
LIGHTING STRIKES. SNOW LEVELS WILL ALSO DROP DOWN TO AS LOW AS
4000 FEET IN SPOTS...ALTHOUGH AS IS ALMOST ALWAYS THE CASE
HERE...THE MAIN ISSUE WILL BE HOW MUCH PRECIPITATION WILL OCCUR AS
THE COLDEST AIR MOVES INTO OUR AREA. BEST SHOT FOR SEEING ANY
ACCUMULATIONS WILL BE THE HIGHEST PEAKS IN MONTEREY COUNTY WHERE
SEVERAL INCHES COULD FALL. SHOWERS WILL DIMINISH NORTH TO SOUTH LATE
SATURDAY INTO SUNDAY.

RAINFALL AMOUNTS ARE NOT EXPECTED TO BE SUBSTANTIAL WITH URBAN
SPOTS GENERALLY LOOKING AT LESS THAN A QUARTER OF AN INCH.
ISOLATED HIGHER ELEVATION SPOTS IN MONTEREY AND SAN BENITO
COUNTIES COULD PICK UP AROUND HALF AN INCH. BIGGER IMPACT WILL BE
ANY SMALL HAIL STORMS THAT WILL LEAD TO VERY SLICK ROADWAYS.

AFTER A BREAK IN THE WEATHER FOR MOST OF SUNDAY INTO MONDAY
MORNING A SECOND SYSTEM WILL DROP DOWN FROM THE NORTH AND BRING
ANOTHER ROUND OF SHOWERS TO OUR CWA. MODELS ARE ONLY IN FAIR
AGREEMENT WITH THE PRECIPITATION POTENTIAL FOR THIS SECOND
PIECE...SO FOR NOW WILL KEEP POP VALUES ON THE LOW SIDE. EVEN IF
WE RECEIVE LITTLE RAINFALL FROM THIS SECOND FEATURE...IT SHOULD
HELP TO DROP TEMPERATURES A FEW DEGREES.

&&

.AVIATION...AS OF 9:20 AM PST WEDNESDAY...A FEW PATCHY CIGS AROUND
THE BAY AREA EARLY THIS MORNING...BUT THEY HAVE SINCE DISSIPATED
FROM THE TERMINALS. VFR CONDITIONS FORECAST FOR TODAY WITH A FEW
PASSING HIGH CLOUDS. GUSTY WINDS POSSIBLE THIS AFTERNOON. TONIGHT
IS A LITTLE TRICKY AS SOME OF GUIDANCE SUGGESTS AN INCREASE IN LOW
LEVEL MOISTURE...BUT THE N-S GRADIENT BEGINS TO INCREASE. GIVEN
THAT SET UP DECIDED TO STICK WITH A SCT DECK FOR SF BAY...BUT
COULD SOME SOME BKN CIG LIKE WE SAW THIS AM. MONTEREY BAY HAS A
BETTER CHANCE FOR CIGS TOMORROW MORNING AND INCLUDED THEM IN THE
TAF. OVERALL CONF IS MEDIUM.

VICINITY OF KSFO...VFR CONDITIONS THROUGH ENTIRE FORECAST. PATCHY
CIGS POSS TOMORROW...BUT CONF IS NOT HIGH ENOUGH TO PUT THEM IN
THE TAF AT THIS TIME. GUSTY WINDS LATER THIS AFTERNOON AS KSFO.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR CONDITIONS TODAY. CIGS RETURNING
TONIGHT AFTER 00Z WITH MVFR TO POSS IFR CONDITIONS POSS.

&&

.MARINE...AS OF 3:00 PM PST WEDNESDAY...HIGH PRESSURE OFF THE
NORTHERN CALIFORNIA COAST WILL LEAD TO GUSTY NORTHERLY WINDS ALONG
THE CENTRAL COAST. THE GUSTY WINDS WILL PRODUCE LOCALLY HAZARDOUS
CONDITIONS WITH STEEP WIND WAVES AND FRESH SWELL. WINDS WILL
REMAIN GUSTY INTO THE THE WEEKEND. AN APPROACHING STORM SYSTEM
WILL BRING A CHANCE OF SHOWERS TO THE REGION THURSDAY THROUGH
WEEKEND.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...SCA...PT ARENA TO PT REYES 0-10 NM
             SCA...PT REYES TO PIGEON PT 0-10 NM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM
             SCA...PT ARENA TO PT REYES 10-60 NM
             SCA...PT REYES TO PIGEON PT 10-60 NM
             SCA...PIGEON PT TO PT PINOS 10-60 NM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM

&&

$$

PUBLIC FORECAST: BELL
AVIATION/MARINE: MM

VISIT US AT WEATHER.GOV/SANFRANCISCO

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




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