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000
FXUS62 KTBW 180755
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
355 AM EDT SAT MAY 18 2013

.SYNOPSIS...
ALOFT THERE WAS A TROUGH FROM BRITISH COLUMBIA COASTAL WATERS
TO NORTHERN NV/UT...RIDGING OVER THE U.S. PLAINS REACHED NORTH
TO THE CANADIAN PRAIRIES...A SHORT WAVE TROUGH WAS OVER THE
OHIO VALLEY-GULF COASTAL STATES...AND TROUGHING OVER LABRADOR
EXTENDED SOUTH TO OFFSHORE NEW ENGLAND. AT THE SURFACE...
A FRONTAL BOUNDARY STRETCHED ACROSS THE CONUS FROM THE
CENTRAL ROCKIES TO OFFSHORE THE MID-ATLANTIC COAST...A DRY
LINE WAS IN FAR WESTERN OK/TX...HIGH PRESSURE SPRAWLED FROM
JAMES BAY DOWN ACROSS THE LOWER GREAT LAKES AND NEW ENGLAND...
AND HIGH PRESSURE OVER THE OPEN ATLANTIC RIDGED WEST/ ALONG
LATITUDE 30 NORTH/ ACROSS FL/GA TO THE WESTERN GULF COAST
REGION.

&&

.SHORT TERM (TODAY - MONDAY)...
THE UPPER RIDGE OVER THE PLAINS PUSHES EAST TO THE APPALACHIAN
RANGE...WITH THE SHORT WAVE TROUGH MOVING TO THE MID-ATLANTIC
STATES THEN BUILDING SOUTHWARD TO THE SE U.S. COASTAL AREA. THE
ATLANTIC HIGH PRESSURE CONTINUES TO RIDGE ALONG OR JUST SOUTH OF
LATITUDE 30 NORTH AS IT GETS REINFORCED BY HIGH PRESSURE
SETTLING SOUTH FROM NEW ENGLAND.

THE SHORT WAVE TROUGH MOVING BY TO THE NORTH TODAY THEN SETTLING IN
TOWARD THE AREA BY MON WILL PROVIDE SOME ENERGY AND COOLER
TEMPERATURES ALOFT...500MB DROPS FROM AROUND -9 TO NEAR -12 DEGREES.
WHILE THE SURFACE RIDGE AXIS MEANDERS AROUND SOME IT/S AXIS STAYS
NORTH OF THE CWA...WITH SOUTHEASTERLY LOW LEVEL FLOW INCREASING
MOISTURE WITH FORECAST PRECIPITABLE WATER VALUES GOING FROM 1.1-1.2
TO 1.5-1.8 INCHES BY MON. THE SE FLOW WILL BE RELAXED ENOUGH FOR SEA
BREEZES EACH AFTERNOON. THESE SEA BREEZES ALONG WITH THE INCREASING
MOISTURE AND ENERGY AND COOLER TEMPERATURES ALOFT WILL RESULT IN
SLIGHT CHANCE TO CHANCE SHOWERS/STORMS WITH THE TIMING GENERALLY
AFTERNOON AND EARLY EVENING ALTHOUGH CONVECTION MAY START EARLIER
MON AS THE SHORT WAVE TROUGH SETTLES TOWARD THE AREA. THE POPS
RANGE FROM 20 TO 40 PERCENT WITH HIGHEST VALUES INLAND.
TEMPERATURES WILL RUN NEAR NORMAL TO A COUPLE OF DEGREES ABOVE.

.LONG TERM (MONDAY NIGHT-FRIDAY)...
SURFACE HIGH PRESSURE WILL BE IN PLACE ACROSS THE AREA THROUGH
THURSDAY WITH THE RIDGE AXIS NORTH OF THE AREA...AS A WEAK TROUGH
REMAINS IN PLACE ALOFT. GENERALLY E/SE WINDS WILL BE IN PLACE WITH
AN AFTERNOON SEA BREEZE DEVELOPING EACH DAY. AMPLE MOISTURE WILL
ALLOW FOR SCATTERED AFTERNOON/EVENING THUNDERSTORMS TO DEVELOP EACH
DAY ALONG SEA BREEZE AND OUTFLOW BOUNDARIES. HAVE KEPT RAIN CHANCES
AT 30-40 PERCENT WITH THE CONVECTION. TEMPERATURES WILL BE IN THE
MID 60S-LOWER 70S EACH MORNING AND IN THE MID 80S COASTAL TO LOWER
90S INLAND EACH AFTERNOON. FOR FRIDAY...A WEAKENING COLD FRONT/AREA
OF WEAK LOW PRESSURE WILL MOVE INTO THE AREA. THIS WILL SHIFT WINDS
TO THE WEST THROUGH THE DAY AND PULL IN A LITTLE DRIER AIR. HAVE
LOWERED RAIN CHANCES TO 20-30 PERCENT FOR THE AFTERNOON. HIGHS WILL
AGAIN BE IN THE UPPER 80S TO LOWER 90S.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS. AN AFTERNOON SEA
BREEZE WILL TURN PREVAILING E/SE WINDS TO THE W/NW THROUGH THE
AFTERNOON AND EARLY EVENING. CEILINGS SHOULD GENERALLY REMAIN VFR
WITH ISOLATED RAIN CHANCES INLAND THAT HAVE LEFT OUT OF THE TAFS FOR
NOW.

&&

.MARINE...
THE RIDGE AXIS OF ATLANTIC HIGH PRESSURE WILL RESIDE NORTH OF THE
WATERS THROUGH MID-WEEK WITH EASTERLY TO SOUTHEASTERLY WINDS. THE
GRADIENT WILL BE RELAXED ENOUGH TO ALLOW AFTERNOON SEA BREEZES TO
SHIFT WINDS TO ONSHORE NEAR THE COAST. THE MAIN CONCERN WILL BE
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS.

&&

.FIRE WEATHER...
ISOLATED INLAND LOCATIONS MAY SEE RELATIVE HUMIDITY VALUES APPROACH
BUT NOT REACH 35 PERCENT THIS AFTERNOON. OTHERWISE INCREASING
MOISTURE WILL KEEP MINIMUM RH VALUES ABOVE 40 PERCENT INTO EARLY
NEXT WEEK.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  89  71  89  72 /  10  10  30  10
FMY  91  72  90  71 /  10  10  30  10
GIF  91  70  90  70 /  30  20  30  20
SRQ  87  70  87  70 /  10  10  30  10
BKV  91  66  88  66 /  10  10  30  10
SPG  87  73  87  74 /  10  10  30  10

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.

&&

$$

SYNOPSIS/SHORT TERM/MARINE/FIRE WEATHER...09/RUDE
LONG TERM/AVIATION...24/COLSON