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

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000
FXUS66 KMTR 150620
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1120 PM PDT SUN SEP 14 2014

.SYNOPSIS...A MINOR COOLING TREND BACK TO MORE SEASONABLE
TEMPERATURES WILL CONTINUE MONDAY AND TUESDAY AS ONSHORE FLOW WILL
BECOME ESTABLISHED WITH A WEAK TROUGH OFFSHORE. A STRONGER SYSTEM
WILL APPROACH FAR NORTHERN CALIFORNIA BY WEDNESDAY BRINGING A
SLIGHT CHANCE OF SHOWERS TO THE NORTH BAY LATER WEDNESDAY INTO
THURSDAY. THAT SYSTEM WILL EVENTUALLY CUT OFF OVER CENTRAL
CALIFORNIA BUT ANOTHER RIDGE WILL BUILD OVER THE BAY AREA AND
NORTHERN CALIFORNIA BY NEXT WEEKEND AND BEYOND.

&&

.DISCUSSION...AS OF 8:52 PM PDT SUNDAY...SKIES ARE NOW MOSTLY
CLEAR TO CLEAR OVER THE REGION. A FEW HIGH CLOUDS ARE DRIFTING
EASTWARD OVER THE EASTERN PACIFIC AHEAD OF AN UPPER LEVEL LOW
PRESSURE AREA LOCATED APPROXIMATELY 800 MILES WEST OF SAN
FRANCISCO.

A NEW TROUGH FROM THE GULF OF ALASKA WILL MOVE SOUTHEAST AND MERGE
WITH THE AFOREMENTIONED EPAC UPPER LOW PRESSURE AREA THEN MOVE EAST
TO CALIFORNIA BY MID-WEEK. THE LOW PRESSURE AREA WILL BRING A CHANCE
OF LIGHT RAIN TO THE NORTHERN BAY AREA WEDNESDAY NIGHT AND
THURSDAY. THE NEWEST 00Z NAM MODEL SHOWS VERY LIGHT QPF ARRIVING
WEDNESDAY NIGHT WITH VERY LIGHT QPF THURSDAY MORNING AS FAR SOUTH
AS SAN MATEO COUNTY. RAINFALL AMOUNTS OVERALL LOOK TO BE LIGHT
GENERALLY UNDER A 1/10 INCH.

PLENTY OF TROPICAL MOISTURE WITH THE REMNANTS OF "ODILE" WILL
MOVE NORTHEAST INTO NORTHERN MEXICO AND EVENTUALLY THE DESERT
SOUTHWEST THIS WEEK.

FORECAST UNCERTAINTY IN THE EXTENDED IS MODERATE TO HIGH. BY NEXT
WEEK THE ECMWF AND GFS SHOW INCREASED UPPER LEVEL RIDGING DEVELOPING
OVER CA. THE GEM MODEL DIFFERS IN SOLUTION SHOWING AN UPPER LEVEL
TROUGH MOVING OFF THE EASTERN PACIFIC.

&&

.AVIATION...AS OF 11:00 PM PDT SUNDAY...SKIES REMAIN CLEAR ACROSS
THE REGION. CIGS EXPECTED TO RETURN BETWEEN 09Z-12Z. THE MARINE
LAYER HAS GRADUALLY DEEPENED TO AROUND 1400 FEET AS AN UPPER
TROUGH OFF THE COAST APPROACHES THE REGION. LIGHT ONSHORE FLOW
WILL PERSIST THROUGH MONDAY MORNING THEN IS EXPECTED TO STRENGTHEN
IN THE AFTERNOON. MODERATE CONFIDENCE.

VICINITY OF KSFO...VFR CONDITIONS WILL CONTINUE THROUGH LATE
TONIGHT. CIGS ANTICIPATED TO RETURN AFTER 12Z. CLEARING EXPECTED
BETWEEN 15Z-18Z MONDAY MORNING. LIGHT WEST WINDS OF 5 TO 10 KT
WILL CONTINUE THROUGH MONDAY MORNING. MODERATE SEABREEZE OF 10 TO
20 KT EXPECTED MONDAY AFTERNOON. MODERATE CONFIDENCE.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WILL CONTINUE
THROUGH LATE TONIGHT. CIGS ANTICIPATED TO RETURN AROUND 12Z WITH
AN EARLY CLEARING BETWEEN 16Z-17Z EXPECTED. LIGHT WINDS. MODERATE
CONFIDENCE.

&&

.MARINE...AS OF 9:00 PM PDT SUNDAY...GENERALLY LIGHT ONSHORE FLOW
AND GENTLE SEAS WILL CONTINUE THROUGH MUCH OF THE UPCOMING WORK
WEEK. MEANWHILE...A LONG PERIOD SOUTHWEST SWELL WILL BEGIN TO
BUILD INTO THE WATERS AND CONTINUE THROUGH MIDWEEK.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...NONE.

&&

$$

PUBLIC FORECAST: CANEPA
AVIATION/MARINE: CW

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