SFOAFDMTR (07/04/09 1036)


FXUS66 KMTR 041736
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA CA
1035 AM PDT SAT JUL 4 2009

.DISCUSSION...AS OF 9:05 AM PDT SATURDAY...STRATUS IS DEEPER THIS
MORNING THAN YESTERDAY WITH THE FORT ORD PROFILER INDICATING A
MARINE LAYER APPROACHING 2000 FEET DEEP. THE CURRENT VISIBLE
SATELLITE IMAGE IS SHOWING STRATUS WELL INTO THE EAST BAY AREA AND
IT HAS ALSO PUSHED DEEP INTO THE SALINAS VALLEY. THESE LOW CLOUDS
ARE EXPECTED TO CLEAR OUT OF THE SAN FRANCISCO BAY AREA BY 1100 AM
PDT AND THE MONTEREY BAY AREA SHOULD SEE CLEAR SKIES BY 1200 PM
PDT.

THE BIG CONCERN OF THE DAY WILL BE WHETHER OR NOT THERE WILL BE
LOW CLOUDS TONIGHT FOR THE FIRE WORKS. LOW CLOUDS ARE EXPECTED TO
RETURN TO THE DISTRICT TONIGHT BUT THEY WILL NOT AFFECT THE SAN
FRANCISCO BAY AREA UNTIL AFTER MIDNIGHT. UNFORTUNATELY...STRATUS IS
EXPECTED TO RETURN TO THE MONTEREY BAY SANTA CRUZ AREA AROUND 8:00
OR 9:00 PM PDT. OTHERWISE A PLEASANT DAY IS IN STORE FOR THE
FORECAST AREA WITH HIGH TEMPERATURES EXPECTED TO BE IN THE UPPER
60S TO LOW 70S ALONG THE COAST AND UPPER 70S TO LOW 90S INLAND.

CURRENTLY THE WATER VAPOUR IMAGE IS SHOWING A TROUGH OFF OF THE
PACIFIC NORTHWEST...CENTERED AT ABOUT 140 WEST AND 43 N. THE MODEL
SOLUTIONS HAVE INITIALIZED WELL WITH THIS FEATURE AND MOVE IT INTO
NORTHERN CALIFORNIA AND SOUTHERN OREGON BY SUNDAY EVENING. AS THE
LOW SLIDES INLAND OVER THE PACIFIC NORTHWEST QUASI ZONAL FLOW
MOVES INTO THE CWA. 500MB HEIGHTS ARE PROGGED TO FALL A BIT WITH THE
1200 UTC GFS SHOWING THE GREATEST COOLING WEDNESDAY. THE GFS IS
FORECASTING 850 MB TEMPERATURES AROUND 14 DEGREES CELSIUS BY
WEDNESDAY AFTERNOON WHICH IS 4 DEGREES WARMER THAN PREVIOUS RUNS.

&&

.AVIATION...AS OF 10:35 AM SATURDAY...WIDESPREAD STRATUS STILL OVER
MUCH OF THE AREA THIS MORNING. EXPECT LATER BURNOFF AT ALL TERMINALS
TODAY AS COMPARED TO YESTERDAY. THE MARINE LAYER IS DEEPER THAN
YESTERDAY AND IS APPROX AT 2K FEET WITH A STRONGER SFO-SAC GRADIENT
OF 2.3 MB.

VICINITY OF KSFO...KSFO IS IN A CLEAR PATCH WITH SCATTERED
CLOUDS AT ABOUT 1800 FEET. KOAK STILL HAS CEILINGS...WHICH
SHOULD CLEAR OFF WITHIN THE HOUR. AFTERNOON GUSTY NW WINDS WILL BE
POSS AT KSFO. STRATUS WILL MOVE IN AGAIN TONIGHT WITH SIMILAR
RESULTS.

KSFO BRIDGE APPROACH...CIGS AND BURN OFF TIME WILL BE LATER
THAN AT KSFO. EXPECT CLEARING BY 19Z.

MONTEREY BAY TERMINALS...STRATUS OVER MRY AND SNS THROUGH 19Z.
STRATUS WILL ONCE AGAIN MAKE AN EARLY RETURN TONIGHT.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDA...SCA...SF BAY STARTING AT 11 AM.

&&



PUBLIC FORECAST: LARRY
AVIATION/MARINE: MM

NWS ON THE WEB AT WEATHER.GOV/SANFRANCISCO