SFOAFDMTR (05/24/13 1447)


FXUS66 KMTR 242151
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
251 PM PDT FRI MAY 24 2013

.DISCUSSION...AS OF 2:47 PM PDT FRIDAY...COOL WEATHER AHEAD WITH A
CHANCE FOR MUCH NEEDED RAIN EARLY NEXT WEEK.

AFTERNOON VISIBLE SATELLITE AND METAR OBSERVATIONS INDICATE MOSTLY
CLEAR SKIES ACROSS THE REGION. A FEW LINGERING LOW CLOUDS REMAIN
ALONG THE SAN MATEO COAST AND AROUND MONTEREY PENINSULA...BUT
OTHERWISE PRETTY NICE AFTERNOON. 24 HOUR TRENDS ALSO REVEAL THAT
MANY LOCATIONS ARE RUNNING A FEW DEGREES WARMER THAN
YESTERDAY...ESPECIALLY INTERIOR LOCATIONS.

SYNOPTICALLY SPEAKING...A NEARLY STATIONARY UPPER LEVEL TROUGH OFF THE
PAC NW COAST CONTINUES TO BE THE DOMINANT WEATHER FEATURE FOR MUCH
OF THE WEST COAST. 

SHORT TERM(TONIGHT-MONDAY)...
THE AFOREMENTIONED TROUGH WILL REMAIN THROUGH THE SHORT TERM AS A
SERIES OF UPPER LOWS SWING THROUGH THE TROUGH. AS A
RESULT...UNSEASONABLY COOL WEATHER WILL CONTINUE THROUGH MUCH OF
THE SHORT TERM. IN ADDITION...MODEL GUIDANCE HAS BEEN RATHER
PERSISTENT WITH BRINGING A STRONG UPPER LOW THROUGH THE TROUGH AND
TOWARD THE CA COAST ON MONDAY RESULTING IN RAIN CHANCES. MODEL
GUIDANCE HAS HAD A DIFFICULT TIME WITH THE EXACT TIMING OF PRECIP
ON MONDAY...BUT CONSENSUS DEVELOPS RAIN OVER THE N BAY EARLY
MONDAY AND THEN GRADUALLY SPREADING RAIN SOUTHWARD THROUGH EARLY
TUESDAY. RAINFALL AMOUNTS APPEAR TO BE RATHER LIGHT...UP TO A
QUARTER OF AN INCH FOR THE N BAY AND A FEW HUNDREDTHS TO A TENTH A
AN INCH SOUTHWARD. NONE THE LESS...PERSONS WITH OUTDOOR ACTIVITIES
ON MEMORIAL DAY MAY WANT TO THINKING ABOUT PACKING RAIN GEAR FOR
SOME AFTERNOON SHOWERS.

THE PERSISTENT ONSHORE FLOW AND COOL AIR ALOFT WILL ALSO PRODUCE
UN-SUMMER LIKE TEMPERATURES. MANY LOCATIONS OVER THE WEEKEND WILL
BE A FEW DEGREES BELOW NORMAL AND BY MONDAY SOME LOCATIONS WILL BE
AS MUCH AS 10 BELOW NORMAL. HIGHS FOR THE UP COMING WEEKEND WILL
GENERALLY BE IN THE 60S ALONG THE COAST AND 70S TO NEAR 80 INLAND.
MONDAY WILL BE THE COOLEST DAY OF THE SHORT TERM WITH MANY
LOCATIONS STRUGGLING TO BREAK 70 DEGREES.

LONG TERM(TUESDAY-FRIDAY)...
A FEW LINGERING SHOWERS WILL BE POSSIBLE TUESDAY AS THE UPPER LOW
EXITS THE REGION. THE REST OF THE LONG TERM WILL FEATURE A GRADUAL
WARMING AND DRYING TREND WITH MORE SEASONABLE TEMPERATURES.


&&

.AVIATION...AS OF 10:30 AM PDT FRIDAY...VFR CONDITIONS WILL
PREVAIL THROUGH MANY OF THE TERMINALS THROUGH AT LEAST THE EVENING
HOURS. MODERATE CONFIDENCE. ONSHORE FLOW WILL INCREASE EARLY THIS
AFTERNOON AND CONTINUE THROUGH THE EVENING HOURS. LATEST SHORT
TERM MODEL GUIDANCE SUGGESTS PATCHY STRATUS AT MANY OF THE
TERMINALS LATE TONIGHT. HOWEVER...THE SHORT TERM GUIDANCE HAS BEEN
PERFORMING POORLY IN THE LAST FEW DAYS...SO STRATUS WAS ONLY ADDED
TO THE MONTEREY BAY. LOW CONFIDENCE.

VICINITY OF KSFO...VFR CONDITIONS THROUGH THE FORECAST. MODERATE
TO HIGH CONFIDENCE. MODERATE WEST WINDS THIS AFTERNOON...WITH
GUSTS PEAKING AROUND 30 KT BETWEEN 21Z TODAY AND 03Z SATURDAY.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO. 

MONTEREY BAY AREA TERMINALS... VFR CONDITIONS THROUGH AT LEAST
06Z. LOW CONFIDENCE. MODERATE ONSHORE WINDS THIS AFTERNOON WITH A
RETURN TO STRATUS AND POSSIBLE IFR CIGS AS EARLY AS MIDNIGHT.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...SCA...PIGEON PT TO PT PINOS 0-10 NM UNTIL 3 AM
             SCA...PT ARENA TO PIGEON PT 10-60 NM
             SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM
             SCA...PT ARENA TO PT REYES 0-10 NM
             SCA...PT REYES TO PIGEON PT 0-10 NM
             SCA...SF BAY UNTIL 9 PM
             SCA...MRY BAY UNTIL 9 PM

&&



PUBLIC FORECAST: MM
AVIATION/MARINE: RILEY

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