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 271602
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
902 AM PDT FRI MAR 27 2015

.SYNOPSIS...A RETURN OF COASTAL FOG AND LIGHT ONSHORE FLOW WILL
MEAN COOLER TEMPERATURES TODAY...ESPECIALLY NEAR THE COAST.
ONSHORE FLOW WILL WEAKEN ON SATURDAY... AND RESULT IN MOSTLY CLEAR
SKIES AND WARMING TEMPERATURES FOR SUNDAY. COOLER TEMPERATURES ARE
THEN EXPECTED BEGINNING ON MONDAY. DRY WEATHER TO PERSIST THROUGH
THE FORECAST PERIOD.

&&

.DISCUSSION...AS OF 08:59 AM PDT FRIDAY...SHORT TERM CONCERNS THIS
MORNING WILL BE FOG. INCREASED ONSHORE FLOW AND LOW LEVEL MOISTURE
HAS LED TO A SHALLOW MARINE LAYER. PROFILERS AND SODARS INDICATE
A MARINE LAYER DEPTH OF A FEW HUNDRED FEET. THE SHALLOW NATURE HAS
ALSO PRODUCED SOME PATCHY DENSE FOG...ESPECIALLY ALONG THE
IMMEDIATE COASTLINE AND LOCALLY INLAND TO BOTH BAYS. A HANDFUL OF
SITES ARE CURRENTLY REPORTING VISIBILITIES LESS THAN ONE QUARTER
OF A MILE.

BURN OFF OF THE CLOUDS/FOG THIS MORNING WILL BE GRADUAL DESPITE
THE SHALLOW NATURE THANKS TO INCREASED ONSHORE FLOW (SFO-SAC
GRADIENT IS UP).

THAT BEING SAID...SOME PATCHY LOW CLOUDS MAY LINGER ALONG THE
COAST THROUGH THE DAY...BUT MUCH OF THE BAY AREA WILL BE MOSTLY
SUNNY TODAY. DESPITE AMPLE SUNSHINE THE COOLER AIR AND INCREASED
ONSHORE FLOW WILL LEAD TO A NOTICEABLE COOL DOWN TODAY. THE 24
HOUR TEMP CHANGE WILL BE AS MUCH AS 12 DEGREES COLDER THAN
YESTERDAY. HOWEVER...DESPITE THE COOL DOWN IT SHOULD STILL BE A
PLEASANT DAY WITH HIGHS IN THE 70S AND 80S INLAND AND 60S ALONG
THE COAST.

FORECAST IS ON TRACK AND NO UPDATE IS NEEDED.

&&

.PREV DISCUSSION...AS OF 3:03 AM PDT FRIDAY...SATURDAY SHOULD
SEE SIMILAR TEMPERATURES WITH 60S AND 70S MOST AREAS...AND UP TO
THE MID 80S FAR INLAND AREAS. A WEAK RIDGE OF HIGH PRESSURE WILL
THEN BUILD OVER THE WEST COAST ON SUNDAY FOR SLIGHT WARMING. BY
EARLY NEXT WEEK...HOWEVER...A TROUGH IS PROGGED TO BRUSH ACROSS
THE WEST COAST INCLUDING NORTHERN CALIFORNIA. THIS WILL BRING
COOLER TEMPERATURES TO THE DISTRICT BY TUESDAY AND
WEDNESDAY...WITH HIGHS EXPECTED TO BE IN THE 60S AND 70S. RAIN
CHANCES WITH THIS TROUGH WILL REMAIN WELL TO THE NORTH. ZONAL FLOW
ALOFT TO MAINTAIN ACROSS THE WEST COAST THROUGH THE REMAINDER OF
THE FORECAST PERIOD.

&&

.AVIATION...AS OF 4:51 AM PDT FRIDAY...THE CURRENT SATELLITE IR
FOG PRODUCT IS SHOWING MOSTLY CLEAR SKIES AROUND THE FORECAST AREA
THIS MORNING WITH THE EXCEPTION OF LOW CLOUDS AND FOG ALONG THE
IMMEDIATE COAST...IMPACTING KSNS AND KMRY. A LARGE FIELD OF
STRATUS ALSO IS PRESENT OVER OCEAN ALONG THE CALIFORNIA COAST AT
THIS HOUR.

A LOW PRESSURE SYSTEM IS PUSHING TOWARDS THE PACIFIC NORTHWEST
WHICH WILL DRAG A COLD FRONT INTO NORTHERN CALIFORNIA THIS
MORNING. THIS COLD FRONT MAY PUSH STRATUS INTO THE TERMINALS BY
LATE AFTERNOON EARLY EVENING. IN ADDITION TO THIS FRONT THE LOCAL
PRESSURE GRADIENT IS EXPECTED TO INCREASE...PROMOTING MODERATE
GUSTY WINDS LATER THIS MORNING INTO THE AFTERNOON AND EVENING
HOURS.

VICINITY OF KSFO...VFR IS EXPECTED TO PREVAIL TODAY WITH STRATUS
POSSIBLE THIS EVENING. GUSTY WEST WINDS WILL REACH 15 TO 20 KT
THIS AFTERNOON WITH GUSTS TO 25 KT.

CONFIDENCE IS HIGH.

SFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...GROUND FOG WILL REDUCE VIS TO AROUND
1/4SM THIS MORNING BUT IS EXPECTED TO BURN OFF BY AROUND 1600Z.
HOWEVER...ONCE THE FOG BURNS OFF SCT007-012 WILL LINGER AROUND
THROUGH THIS AFTERNOON. AND EARLY RETURN OF BKN008 IS LIKELY BY
0200Z. WINDS ARE EXPECTED TO INCREASE OUT OF THE WEST TODAY
REACHING 10 TO 15 KT THIS AFTERNOON WITH GUSTS TO 20 KT POSSIBLE.

CONFIDENCE IS MODERATE.

&&

.MARINE...AS OF 2:45 AM PDT FRIDAY...THE SURFACE PRESSURE
GRADIENT WILL INCREASE TODAY AS A STORM SYSTEM PASSES TO THE
NORTH. THIS WILL RESULT IN INCREASING NORTH WESTERLY WINDS ACROSS
THE COASTAL WATERS. THE STRENGTHENING WINDS WILL GENERATE STEEP
FRESH SWELL WHICH WILL PERSIST THROUGH THE WEEKEND AND POSSIBLY
INTO THE FIRST HALF OF NEXT WEEK.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...SCA...PT ARENA TO PT REYES 10-60 NM FROM 2 PM
             SCA...PT REYES TO PIGEON PT 10-60 NM FROM 2 PM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM FROM 5 PM
             SCA...PIGEON PT TO PT PINOS 10-60 NM FROM 5 PM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM FROM 5 PM
             SCA...PT ARENA TO PT REYES 0-10 NM FROM 2 PM
             SCA...PT REYES TO PIGEON PT 0-10 NM FROM 5 PM
             SCA...SF BAY NORTH OF THE BAY BRIDGE FROM 2 PM
             SCA...SF BAY SOUTH OF THE BAY BRIDGE FROM 2 PM

&&

$$

PUBLIC FORECAST: MM
AVIATION/MARINE: LARRY

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.