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

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000
FXUS66 KMTR 311738
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1038 AM PDT THU JUL 31 2014

.SYNOPSIS...THE TYPICAL SUMMER WEATHER PATTERN HAS RETURNED TO THE
CENTRAL COAST WITH NIGHT/MORNING COASTAL LOW CLOUDS AND FOG
STRETCHING INTO THE VALLEYS WITH CLEARING SKIES IN THE AFTERNOON
HOURS. NEAR NORMAL TEMPERATURES AND DRY WEATHER EXPECTED THROUGH
THE FORECAST PERIOD.

&&

.DISCUSSION...AS OF 9:15 AM PDT THURSDAY...THE CURRENT VISIBLE
SATELLITE IMAGE IS SHOWING STRATUS ALONG THE COAST AND WELL INTO
THE INLAND VALLEYS THIS MORNING. WHEN I LEFT THE HOUSE THIS
MORNING THERE WAS PLENTY OF DRIZZLE ON MY CAR AND DRIVEWAY...THE
TYPICAL SUMMER WEATHER PATTERN HAS RETURNED. ALSO EVIDENT ON THE
VISIBLE SATELLITE IMAGE ARE SOME HIGH CLOUDS MOVING IN FROM THE
WEST. THESE CLOUDS ARE ASSOCIATED WITH A 50 KT JET MAX WHICH WILL
PASS OVER THE FORECAST AREA TODAY. THE JET MAX AND CLOUDS ARE NOT
SIGNIFICANT BUT WILL MAKE OUR SKIES A LITTLE MORE INTERESTING TO
LOOK AT ONCE THE LOW CLOUDS BURN OFF.

THE 0000Z ECMWF AND 1200Z GFS40 HAVE INITIALIZED WELL WITH THE
CURRENT SYNOPTIC PATTERN AND REMAIN IN GOOD AGREEMENT THROUGH THE
FORECAST PERIOD. BOTH MODELS MAINTAIN A RIDGE OF HIGH PRESSURE
OVER THE WESTERN CONUS THROUGH THE WEEKEND WITH A WEAK UPPER LEVEL TROUGH
DEVELOPING ALONG THE COAST BY THE BEGINNING OF NEXT WEEK. AT THE
SURFACE A THERMAL THROUGH POSITIONED ALONG THE COAST WILL PROMOTE
WARM SEASONAL TEMPERATURES INLAND AND COOL TEMPERATURES ALONG THE
COAST.

&&

.PREV DISCUSSION...AS OF 3:03 AM PDT THURSDAY...HIGH CLOUDS FROM
THE FORMER TROPICAL SYSTEM HERNAN HAVE EXITED THE AREA AND ARE NOW
OVER NEVADA. NOW SATELLITE SHOWS COASTAL STRATUS HAS SPREAD INTO
INLAND AREAS. THE MARINE LAYER DEPTH IS ROUGHLY THE SAME AS 24
HOURS AGO...JUST OVER 1000 FEET DEEP AND THE ONSHORE SURFACE
PRESSURE GRADIENT HAS INCREASED WITH 3.0 MB BETWEEN SFO AND SAC.
CURRENT TEMPERATURES AND DEW POINTS ARE MOSTLY SIMILAR TO THOSE
FROM YESTERDAY AT THIS TIME...ALTHOUGH SOME STATIONS ARE REPORTING
READINGS THAT ARE A FEW DEGREES COOLER.

A BROAD UPPER LEVEL TROUGH OVER THE EASTERN PACIFIC WILL PROVIDE A
DRY SOUTHWEST FLOW ALOFT ACROSS THE DISTRICT THROUGH THE REMAINDER
OF THE WEEK AND INTO THE WEEKEND. ONSHORE FLOW IS EXPECTED TO
INCREASE BY LATE IN THE WEEKEND WHICH WILL ALLOW FOR COOLER AIR TO
FILTER FARTHER INLAND WITH NEAR NORMAL TEMPERATURES EXPECTED.
THERE COULD BE A SLIGHT WARM-UP ONCE AGAIN LATE NEXT WEEK AS HIGH
PRESSURE ALOFT BUILDS WESTWARD INTO CALIFORNIA FROM THE DESERT
SOUTHWEST.

&&

.AVIATION...AS OF 10:30 AM PDT THURSDAY...MARINE LAYER HAS
DEEPENED SLIGHTLY TO AROUND 1500 FT THIS MORNING WITH STRATUS
EXTENDING WELL INLAND. CLEARING IS TAKING PLACE QUICKLY AT THIS
HOUR. CIGS ARE EXPECTED TO RETURN TO MRY BAY HOWEVER MODELS ARE
MIXED ON MARINE LAYER THIS EVENING AROUND SF BAY.

VICINITY OF KSFO...VFR TODAY. WEST WINDS TO NEAR 20 KT THIS
AFTERNOON. CIGS LATE IF AT ALL.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...CIGS CLEARING WITHIN THE NEXT HOUR
OR SO. CIGS RETURN TONIGHT.

&&

.MARINE...AS OF 04:24 AM PDT THURSDAY...NORTHERLY FLOW WILL
INCREASE OVER THE COASTAL WATERS TODAY AS HIGH PRESSURE BUILDS OFF
THE WEST COAST. WINDS WILL BE STRONGEST NORTH OF POINT REYES.
GUSTY WINDS WILL ALSO BE POSSIBLE IN THE SAN FRANCISCO BAY THIS
AFTERNOON AND EVENING. THE INCREASED WINDS WILL PRODUCE STEEPER
WIND WAVES AND LOCALLY HAZARDOUS CONDITIONS. NORTHWEST SWELL WILL
INCREASE FRIDAY AND OVER THE WEEKEND.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...SCA...PT ARENA TO PT REYES 0-10 NM FROM 3 PM
             SCA...PT ARENA TO PT REYES 10-60 NM FROM 3 PM
             SCA...SF BAY NORTH OF THE BAY BRIDGE FROM 1 PM

&&

$$

PUBLIC FORECAST: LARRY
AVIATION: AC
MARINE: MM

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