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

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000
FXUS66 KMTR 030004
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
504 PM PDT MON MAY 2 2016

.SYNOPSIS....DRY AND SEASONABLE CONDITIONS WILL PERSISTS THROUGH
TUESDAY. A WEATHER SYSTEM WILL THEN APPROACH THE CALIFORNIA COAST
BY MIDWEEK AND BRING A CHANCE OF SHOWERS AND POTENTIALLY
THUNDERSTORMS TO THE REGION FROM WEDNESDAY INTO THE START OF THE
UPCOMING WEEKEND. TEMPERATURES WILL ALSO COOL TO NEAR OR BELOW
SEASONAL AVERAGES THROUGH LATE WEEK.

&&

.DISCUSSION...AS OF 01:49 PM PDT MONDAY...A WELL ESTABLISHED
MARINE LAYER THAT RETURNED TO THE REGION YESTERDAY EVENING REMAINS
IN PLACE AND HAS RESULTED IN LOW CLOUDS ALONG MUCH OF THE
COASTLINE. AS A RESULT AND WITH THE RETURN TO A MORE PREDOMINATE
ONSHORE FLOW, TEMPERATURES REGION WIDE THIS AFTERNOON ARE RUNNING
A FEW (INLAND) TO AS MUCH AS 15 DEGREES COOLER (NEAR THE COAST)
COMPARED TO 24 HOURS AGO. MEANWHILE, INLAND AREAS REMAIN UNDER
MOSTLY SUNNY CONDITION WITH TEMPERATURES IN THE 70S TO NEAR 80 IN
THE WARMEST INLAND VALLEY LOCATIONS. DO EXPECT THE LOW CLOUDS TO
PUSH BACK INLAND THIS EVENING AND SPREAD INTO THE VALLEYS
OVERNIGHT. CONDITIONS ON TUESDAY WILL CHANGE VERY LITTLE, YET
COULD SEE A FEW DEGREES OF COOLING INLAND AS ONSHORE FLOW
INCREASES SLIGHTLY.

FOR THE SECOND HALF OF THE WEEK, AN UPPER LEVEL TROUGH IS FORECAST
TO DEVELOP OVER THE EASTERN PACIFIC. AS THE TROUGH APPROACHES THE
COAST, THE FORECAST MODELS SHOW A CLOSED MID/UPPER LEVEL LOW
DEVELOPING OFF OF THE NORTHERN OR CENTRAL CALIFORNIA COAST LATE
WEDNESDAY INTO THURSDAY. THIS WILL RESULT IN COOLER TEMPERATURES
REGION-WIDE AND INCREASED CHANCES FOR ISOLATED TO SCATTERED SHOWERS
FROM WEDNESDAY AFTERNOON THROUGH SATURDAY. WITH THAT SAID,
WIDESPREAD RAINFALL IS NOT EXPECTED AT THIS TIME GIVEN THE LACK OF A
DEEP MOISTURE SOURCE AND STRONGER MID/UPPER LEVEL SUPPORT. HOWEVER,
WITH THE CENTER OF THE LOW FORECAST TO MOVE INLAND OVER THE REGION,
THERE WILL BE A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS LATE THIS
WEEK AS A COLDER AND MORE UNSTABLE AIR MASS REMAINS OVERHEAD. CANNOT
RULE OUT A FEW THUNDERSTORMS WITH SMALL HAIL AS WELL.

THE UPPER LEVEL TROUGH IS THEN FORECAST TO SHIFT INLAND BY SUNDAY AS
AN UPPER LEVEL RIDGE BUILDS OVER THE EASTERN PACIFIC. THIS SHOULD
BRING AN END TO THE UNSETTLED WEATHER CONDITIONS OVER THE REGION
LATE SATURDAY INTO SUNDAY. TEMPERATURES LATE IN THE WEEKEND WILL
ALSO SLOWLY REBOUND BACK TO NEAR SEASONAL AVERAGES.

&&

.AVIATION...AS OF 5:00 PM PDT MONDAY...2000 FOOT MARINE LAYER IN
PLACE. SOUTHERLY FLOW ALONG THE COAST WILL ALLOW STRATUS TO SPREAD
INTO SNS AND MRY EARLY TONIGHT. THE STRATUS WILL SPREAD INTO THE
EAST BAY AFTER 06Z AND AROUND THE SOUTH BAY REACHING SFO LAST. SO
SFO AND THE APPROACH WILL STAY VFR THROUGH THE AIRPORT EVENING
RUSH. AN APPROACHING UPPER LEVEL TROUGH IS EXPECTED TO KEEP
STRATUS IN UNTIL 18Z OR LATER ON TUESDAY.

VICINITY OF KSFO...VFR THROUGH THE AIRPORT EVENING RUSH. MVFR CIGS
SPREADING FROM THE SOUTH REACHING SFO BY 10-11Z. WEST WINDS 14-17
KT THRPUGH 04Z.

SFO BRIDGE APPROACH...SAME AS KSFO. MVFR CIGS OVER THE SOUTHERN
PART OF THE APPROACH AFTER 08-09Z SPREADING NORTH.

MONTEREY BAY TERMINALS...MVFR CIGS POSSIBLY LOWERING TO IFR AFTER
06Z.

&&

.MARINE...AS OF 5:00 PM PDT MONDAY...LIGHT WEST WINDS THIS
EVENING WILL GRADUALLY TURN NW INTO TUESDAY. LIGHT TO MODERATE NW
WIND AND SEAS WILL CONTINUE TUESDAY INTO WEDNESDAY AS A LATE
SEASON UPPER LOW APPROACHES THE REGION PRODUCING SCATTERED SHOWERS
THROUGH THE END OF THE WEEK. LIGHT SEAS MOST OF THE WEEK WILL
BUILD LATE THURSDAY INTO FRIDAY AS THE LOW DEPARTS AND STRONGER NW
WINDS ARRIVE.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...NONE.

$$

PUBLIC FORECAST: RGASS
AVIATION: W PI
MARINE: W PI


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