000
FXUS66 KMTR 231749
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA CA
945 AM PST MON NOV 23 2009

.DISCUSSION...AS OF 9:15 AM PST MONDAY...CLEAR SKIES OVERNIGHT LEAD
TO AREAS OF PATCHY FOG IN THE VALLEYS THIS MORNING. LOW TEMPERATURES
DROPPED INTO THE LOW TO MID 30S IN THE NORTHBAY VALLEYS AND REMAINED
IN THE UPPER 30S TO LOW 40S ELSEWHERE. TODAY WILL BE MOSTLY SUNNY
UNDER A RIDGE OF HIGH PRESSURE ANCHORED OVER THE EASTERN PACIFIC.
UNDER CLEAR SKIES AFTERNOON TEMPERATURES ARE EXPECTED TO REACH INTO
THE 60S.

MODEL SOLUTIONS ARE INDICATING THAT THE RIDGE OF HIGH PRESSURE WILL
MIGRATE SLIGHTLY EAST OVER THE CWA TOMORROW. AT THE SURFACE A
THERMAL TROUGH WILL DEVELOP ALONG THE CENTRAL COAST RESULTING
IN OFFSHORE FLOW. THE COMBINATION OF OFFSHORE FLOW AND THE
EASTWARD MIGRATING RIDGE WILL PUSH TEMPERATURES UP A FEW DEGREE
TOMORROW TO NEAR NORMAL LEVELS FROM MONTEREY NORTH TO AROUND 5
DEGREES ABOVE NORMAL SOUTH OF MONTEREY. THESE PLEASANT DRY
CONDITIONS WILL LAST THROUGH THANKSGIVING DAY.

THANKSGIVING DAY WILL BE MOSTLY DRY ACROSS THE CWA. HOWEVER...THE
MEDIUM RANGE MODELS HAVE BEEN PERSISTENT ON MOVING A TROUGH INTO
THE PACIFIC NORTHWEST. AS THE TROUGH MOVES ONSHORE IT WILL SLIDE A
COLD FRONT ACROSS NORTHERN PORTIONS OF THE CWA. AHEAD OF THE COLD
FRONT WINDS WILL SHIFT OUT OF THE SOUTH ADVECTING WARM AIR INTO
THE CWA. WITH THIS IN MIND FORECASTED TEMPERATURES MAYBE A LITTLE
LOW FOR THANKSGIVING DAY. THEREFORE...WILL TAKE A CLOSER LOOK AT
THE AFTERNOON TEMPERATURE FOR THURSDAY IN THE AFTERNOON FORECAST
PACKAGE. ANOTHER RESULT OF THE COLD FRONT WILL BE A SLIGHT CHANCE
OF PRECIPITATION THURSDAY EVENING WITH THE BEST CHANCE OF
PRECIPITATION IN THE NORTHBAY AREA. HOWEVER...THE 1200 UTC GFS 40
DOES INDICATE PRECIP PUSHING AS FAR SOUTH AS MONTEREY BY EARLY FRIDAY
MORNING.

&&

.AVIATION...AS OF 9:40 AM PST MONDAY...GENERAL NORTHERLY FLOW AND
A DRIER AIRMASS WILL KEEP MOSTLY CLEAR CONDITIONS THROUGH
EVENING.

VICINITY OF KSFO...SKC TODAY AND THIS EVENING. NO WIND CONCERNS.

KSFO BRIDGE APPROACH...SKC.

MONTEREY BAY TERMINALS...SKC TODAY AND THIS EVENING.  SLIGHT CHANCE
FOR SOME LIGHT FOG OVERNIGHT.

&&


.MTR WATCHES/WARNINGS/ADVISORIES...
    .TDY...SMALL CRAFT FOR ROUGH BAR


$$

PUBLIC FORECAST: LARRY
AVIATION/MARINE: WJK

NWS ON THE WEB AT WEATHER.GOV/SANFRANCISCO