000
FXUS66 KMTR 170401
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
901 PM PDT SUN JUN 16 2013

.DISCUSSION...AS OF 9:00 PM PDT SUNDAY...A LONGWAVE UPPER TROUGH
IS CENTERED OFFSHORE ALONG 138W THIS EVENING. A WEAK SHORTWAVE
RIDGE EMBEDDED IN THE WSW FLOW AHEAD OF THE TROUGH MANAGED TO
SUPPRESS THE MARINE LAYER OVER OUR REGION TODAY. IN FACT...THE
MARINE LAYER DEPTH DECREASED FROM ABOUT 2000 FEET YESTERDAY
EVENING DOWN TO JUST 1000 FEET BY MIDDAY TODAY. THE RESULT WAS
EARLY CLEARING FOR INLAND AREAS AND WIDESPREAD CLEARING AT THE
COAST THIS AFTERNOON. WITH EXTRA SUN TODAY...TEMPERATURES WERE
WARMER COMPARED TO YESTERDAY AT NEARLY ALL REPORTING LOCATIONS.

THE MARINE LAYER REMAINS RELATIVELY SHALLOW THIS EVENING...1200
FEET DEEP ON THE OAK SOUNDING AND 1000 FEET DEEP AT FORT ORD.
WOULD EXPECT AT LEAST SOME DEEPENING OF THE MARINE LAYER OVERNIGHT
AND INTO MONDAY AS THE LONGWAVE TROUGH MOVES SLOWLY EASTWARD.
THUS...TEMPERATURES SHOULD COOL AT LEAST A FEW DEGREES ON MONDAY.
MUCH MORE SIGNIFICANT COOLING IS FORECAST FOR TUESDAY AS THE
UPPER TROUGH AXIS APPROACHES THE COAST AND A ROBUST SHORTWAVE
SWINGS THROUGH THE BASE OF THE LONGWAVE TROUGH. A STRONG MARINE
PUSH WILL PROBABLY GET UNDERWAY ON MONDAY NIGHT WITH PATCHY
DRIZZLE LIKELY...ESPECIALLY IN COASTAL AREAS...BY TUESDAY
MORNING. HIGHS ON TUESDAY WILL BE ANYWHERE FROM 7 TO 15 DEGREES
BELOW NORMAL...WITH GREATEST DEPARTURES FROM THE NORM EXPECTED
ACROSS INLAND AREAS. THE TROUGH AXIS IS FORECAST TO SWING INLAND
ON TUESDAY EVENING AND LOCALLY BLUSTERY CONDITIONS ARE EXPECTED IN
THE HILLS AND NEAR THE COAST FROM LATE TUESDAY AFTERNOON THROUGH
TUESDAY EVENING. THE AIRMASS ALOFT WILL COOL CONSIDERABLY BY LATE
TUESDAY...WITH 850 MB TEMPERATURES FORECAST TO DROP BELOW 10 DEG
C. THAT MUCH COOLING ALOFT SHOULD WIPE OUT THE MARINE INVERSION
AND HELP TO BREAK UP THE LOW STRATUS CLOUD DECK. BUT THE
PERSISTENT STRONG AND MOIST ONSHORE FLOW WILL LIKELY MAINTAIN AT
LEAST PARTLY CLOUDY SKIES THROUGH WEDNESDAY. TEMPERATURES ON
WEDNESDAY WILL REMAIN WELL BELOW NORMAL.

THE UPPER TROUGH WILL MOVE WELL EAST OF THE AREA BY THURSDAY AND
UPPER LEVEL RIDGING IS FORECAST TO GRADUALLY STRENGTHEN NEAR THE
WEST COAST FROM THURSDAY THROUGH NEXT WEEKEND. TEMPERATURES ARE
EXPECTED TO WARM BACK UP TO NEAR NORMAL BY FRIDAY AND THEN ABOVE
NORMAL BY SATURDAY.

&&

.AVIATION...AS OF 4:45 PM PDT SUNDAY...MARINE LAYER HAS BECOME
SHALLOWER AND IS NOW AROUND 1200 FEET. FLOW IS ONSHORE BUT STRATUS
IS NOT BANKED UP ALONG THE COAST WHICH SUGGESTS THE STRATUS WILL
BE LATE SPREADING INTO THE SFO BAY AREA.

VICINITY OF KSFO...VFR THROUGH THE AIRPORT EVENING RUSH HOUR.
WEST WINDS TO 25 KT GUSTING AS HIGH AS 30 KT THROUGH 04Z. CLOUDS
WILL START TO MOVE IN AFTER 06Z WITH MVFR CIGS BY 10Z.

KSFO BRIDGE APPROACH...SIMILAR TO SFO.

MONTEREY BAY AREA TERMINALS...STRATUS HAS CLEARED OUT THIS
AFTERNOON BUT LATEST SATELLITE IMAGE SHOWS CLOUDS STARTING TO FORM
AROUND PT PINOS AND THIS WILL EXPAND OVER MRY BAY. IFR CIGS OVER
MRY AND SNS BY 04Z.

&&

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

&&

$$

PUBLIC FORECAST: DYKEMA
AVIATION/MARINE: W PI

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