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

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000
FXUS66 KMTR 311809
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1109 AM PDT FRI JUL 31 2015

.SYNOPSIS...A COOLING TREND CAN BE EXPECTED TODAY AND THROUGH THE
WEEKEND. SUBTROPICAL MOISTURE STREAMING INTO OUR AREA MAY PRODUCE
A FEW ISOLATED SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT.

&&

.DISCUSSION...AS OF 8:35 AM PDT FRIDAY...LINE OF SHOWERS THAT HAD
BEEN ACROSS A PORTION OF MONTEREY AND SAN BENITO COUNTIES HAS
GREATLY DIMINISHED OVER THE PAST 30 MINUTES. IN FACT...LAST COUPLE
OF IMAGES FROM THE KMUX RADAR SHOWS VIRTUALLY NO SHOWER ACTIVITY
LEFT SINCE THE BAND HAS MOVED INTO SANTA CRUZ AND SANTA CLARA
COUNTIES. THE TRIGGER FOR THE SHOWERS APPEARS TO BE A WEAK
VORTMAX/SHORTWAVE CURRENTLY MOVING NORTHWARD THROUGH OUR CWA.
LATEST MODELS IN CONTINUE TO DOWNPLAY THE THREAT OF CONVECTION
THROUGH OUR AREA HOWEVER IN LIGHT OF THE SMALL BAND THAT DEVELOPED
THIS MORNING WILL KEEP A MENTION OF SHOWERS AND THUNDERSTORMS
TODAY FOR ALL LOCATIONS. WILL MAKE ADJUSTMENTS TO THE POPS FOR THE
AFTERNOON SHIFT IF NOTHING FIRES BY THEN.

OVERALL FORECAST PACKAGE LOOKS TO BE ON TRACK.

.PREVIOUS DISCUSSION...KMUX RADAR HAS BEEN SHOWING ECHOES MOVING
FROM SOUTHEAST TO NORTHWEST ACROSS MONTEREY AND SAN BENITO
COUNTIES FOR THE PAST SEVERAL HOURS. SALINAS AIRPORT WAS REPORTING
LIGHT RAIN DURING LAST HOUR`S OBSERVATION...AND THERE IS EVIDENCE
OF A TRACE OF RAIN FALLING WITHIN THE LAST HOUR HERE AT THE
WEATHER OFFICE IN MONTEREY. A FEW OTHER OBSERVATIONS ON MESOWEST
HAVE REPORTED A COUPLE HUNDREDTHS OF AN INCH...LAGUNA
SECA...PEBBLE BEACH TO NAME A FEW. THESE SHOWERS WILL CONTINUE TO
MOVE TO THE NORTHWEST OUT OVER THE OCEAN THIS MORNING. ADDITIONAL
CONVECTION IS EXPECTED TO DEVELOP BY THIS AFTERNOON MAINLY ACROSS
THE HIGHER TERRAIN. SHOWER CHANCES ARE EXPECTED TO WANE BY
SATURDAY MORNING AS THE FLOW BECOMES MORE WESTERLY.

ONSHORE FLOW WILL CONTINUE DURING THE WEEKEND WHICH WILL BRING
COOLER TEMPERATURES TO EVEN INLAND AREAS. BY EARLY NEXT WEEK...AN
UPPER LEVEL LOW OVER THE GULF OF ALASKA WILL DEEPEN AND ITS
ASSOCIATED TROUGH WILL EXTEND ALONG THE WEST COAST. THIS WILL KEEP
COOLER TEMPS ACROSS THE DISTRICT AS WELL AS BREEZY NORTH WINDS
OVER THE COASTAL WATERS AND NEAR-SHORE AREAS.

&&

.AVIATION...AS OF 11:10 AM PDT FRIDAY... FOR 18Z TAFS...
WIDESPREAD VFR CONDITIONS THROUGH THE DAY AS MONSOONAL MOISTURE
SATURATES THE MID LEVELS AND BRINGS SCT TO BKN CLOUDS BETWEEN 12K
TO 20 K FT AGL. ISOLATED SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH A MESO LOW WILL BE MOVING THROUGH THE BAY AREA BTWN 18Z - 21Z
TODAY BUT IMPACTS SHOULD BE MINIMAL. MARINE LAYER RETURNS TONIGHT
AND WILL PERSIST SLIGHTLY LATER INTO THE MORNING THAN THIS
MORNING.

VICINITY OF KSFO... VFR. LIGHT WINDS WILL INCREASE TO AROUND 15
TO 20 KT EXPECTED THIS AFTERNOON. VICINITY SHOWERS EARLY THIS
AFTERNOON. MARINE LAYER RETURNS AOA 07Z SAT.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR WITH A FEW TO SOME MID LEVEL
CLOUDS ALOFT. MARINE LAYER RETURNS AOA 03Z SAT.

&&

.MARINE...AS OF 11:05 AM PDT FRIDAY...LIGHT NORTHWEST WINDS ACROSS
THE COASTAL WATERS TODAY WITH THE STRONGEST WINDS LOCATED IN THE
NORTHERN SAN FRANCISCO BAY... ESPECIALLY AROUND ANGEL ISLAND.
ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THIS MORNING.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...SCA...SF BAY UNTIL 9 PM

&&

$$

PUBLIC FORECAST: BELL/SIMS
AVIATION: DRP
MARINE: CW


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