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

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000
FXUS66 KMTR 050546
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1046 PM PDT WED MAY 4 2016

.SYNOPSIS...MOSTLY CLOUDY AND COOL CONDITIONS WILL PERSIST
THROUGH LATE WEEK AS AN UPPER LEVEL SYSTEM APPROACHES THE COAST.
THIS FEATURE WILL ALSO RESULT IN ISOLATED TO SCATTERED SHOWERS AND
THE POTENTIAL FOR ISOLATED THUNDERSTORMS THROUGH SATURDAY. DRY
WEATHER CONDITIONS WILL LIKELY RETURN BY SUNDAY AND PERSIST INTO
NEXT WEEK ALONG WITH A SLIGHT WARMING TREND AS HIGH PRESSURE
BUILDS OVER THE EASTERN PACIFIC.

&&

.DISCUSSION...AS OF 9:11 PM PDT WEDNESDAY...AN UPPER LEVEL CLOSED
LOW CENTERED AT APPROXIMATELY 36N 127W OFF THE CENTRAL CALIFORNIA
COAST HAS MAINTAINED A STEADY STREAM OF MID AND UPPER LEVEL
CLOUDS ACROSS THE REGION TODAY. TEMPERATURES FELL 5 TO 10 DEGREES
FROM YESTERDAY AS A RESULT OF THE INCREASED CLOUD COVER AND A COOLER
AIRMASS MOVING IN. THE LATEST BLENDED PRECIPITABLE WATER IMAGE
SHOWS PW OF AROUND AN INCH EXTENDING FROM THE PACIFIC NORTHWEST
SOUTHWARD ALONG THE LENGTH OF THE CALIFORNIA COAST. THE BULK OF
THE MOISTURE PLUME CURRENTLY SIT OFF THE COAST HOWEVER AS THIS
SYSTEM SHIFT FURTHER EAST AND CONTINUES TO ADVECT MOISTURE
NORTHWARD ALONG ITS EASTERN FLANK THE PLUME OF MOISTURE WILL MOVE
INLAND ACROSS THE DISTRICT. THIS WILL RESULT IN INCREASED CHANCE OF
PRECIPITATION TONIGHT AND THURSDAY. A FEW ISOLATED THUNDERSTORMS
AND NUMEROUS LIGHTNING STRIKES WERE OBSERVED TODAY OUTSIDE OF OUR
WARNING AREA. THE CHANCE OF ISOLATED THUNDERSTORMS IS ANTICIPATED
THURSDAY AFTERNOON AS THE CENTER OF THE LOW MOVES EAST TOWARD AND
THEN ACROSS SOUTH-CENTRAL CALIFORNIA. INCREASED INSTABILITY AND
MOISTURE WILL LEAD TO SCATTERED SHOWERS AND ISOLATED AFTERNOON
THUNDERSTORMS CAPABLE OF PRODUCING SMALL HAIL.

BY FRIDAY THE LOW IS FORECAST TO MOVE TO THE SOUTH OF OUR CWA
RESULTING IN UNSETTLED WEATHER ACROSS OUR AREA. SHOWERS WILL
LINGER INTO SATURDAY AS MOISTURE CONTINUES TO CIRCULATE AROUND
THIS SYSTEM. SHOWERS WILL BE HIT AND MISS ACROSS THE REGION WITH
ACCUMULATION ANYWHERE FROM A TENTH TO A QUARTER OF AN INCH WITH A
FEW LOCATION POSSIBLY RECEIVING UP TO A HALF INCH.

TEMPERATURES WILL REMAIN BELOW SEASONAL AVERAGES THROUGH SATURDAY
AS THE UPPER LOW REMAINS IN THE VICINITY. WARMER AND DRIER WEATHER
IS FORECAST TO RETURN SUNDAY AS A RIDGE OF HIGH PRESSURE BEING TO
BUILD IN OVER THE EASTERN PACIFIC. MILD AND DRY CONDITIONS ARE
EXPECTED TO CONTINUE INTO THE FIRST HALF OF THE WORK WEEK.

&&

.AVIATION...AS OF 10:45 PM PDT WEDNESDAY...UPPER LOW WAS CENTERED
ABOUT 200 MILES WEST OF KMRY WEDNESDAY EVENING. ACCORDING TO MOST
MODEL DATA...SHOWERS/THUNDERSTORMS CHANCES WILL REMAIN VERY LOW
UNTIL MIDDAY THURSDAY WHEN CONVECTIVE PRECIPITATION CHANCES WILL
INCREASE AS THE LOW APPROACHES THE CENTRAL CALIFORNIA COAST. UNTIL
THEN...MAIN CONCERN IS LOW CLOUDS. MVFR CIGS WILL LIKELY DEVELOP
AT MOST TERMINALS OVERNIGHT AND PERSIST THROUGH MIDDAY THURSDAY.
WINDS LIGHT TO MODERATE FROM THE WEST AND SOUTHWEST.

VICINITY OF KSFO...MVFR CIGS LIKELY TO DEVELOP AROUND 06Z AND
PERSIST THROUGH THURSDAY MORNING. CONFIDENCE MODERATE. SHOWERS MAY
DEVELOP IN VICINITY OF THE TERMINAL ON THURSDAY AFTERNOON. WINDS
LIGHT FROM THE SOUTHWEST THROUGH THE PERIOD.

SFO BRIDGE APPROACH...SIMILAR AS KSFO.

MONTEREY BAY TERMINALS...MVFR CIGS LIKELY TO DEVELOP BY 09Z AND
THEN PERSIST THROUGH THURSDAY MORNING. SHOWERS POSSIBLE IN THE
VICINITY OF KMRY STARTING LATE MORNING THURSDAY. LIGHT WINDS
MAINLY FROM THE WEST OR SOUTHWEST.

&&

.MARINE...AS OF 8:56 PM PDT WEDNESDAY...AN UPPER LOW CENTERED
WEST OF MONTEREY BAY WILL MOVE SLOWLY EAST AND INLAND ACROSS
CENTRAL CALIFORNIA BY LATE IN THE WEEK. THIS LOW WILL RESULT IN
MODERATE NORTHERLY WINDS IN THE OUTER WATERS NORTH OF PT REYES AS
WELL AS A CHANCE OF SHOWERS. LIGHT WINDS WILL PREVAIL ELSEWHERE.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...SCA...PT ARENA TO PIGEON PT 10-60 NM

&&

$$

PUBLIC FORECAST: CW
AVIATION: DYKEMA
MARINE: DYKEMA


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