Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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000
FXUS62 KTBW 220810
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
410 AM EDT MON SEP 22 2014

...THE EQUINOX WHICH OCCURS AT 1029 PM TONIGHT MARKS THE START OF
FALL...

.SYNOPSIS...
ALOFT - A RIDGE REACHED FROM THE SOUTHERN HIGH PLAINS TO THE
CENTRAL CANADIAN PRAIRIES WHILE TROUGHING WAS OVER MUCH OF THE
EASTERN CONUS...EXTENDING FROM QUEBEC TO THE EAST GULF OF MEXICO.
SURFACE - HIGH PRESSURE SPRAWLED ACROSS MUCH OF THE MIDDLE CONUS
WITH A COLD FRONT THAT ARCED FROM NORTHERN TX THROUGH THE GULF
COASTAL STATES TO A LOW PRESSURE AREA IN THE SAINT LAWRENCE RIVER
VALLEY. A DIFFUSE FRONTAL BOUNDARY STRETCHED ACROSS CENTRAL FL WITH
ATLANTIC HIGH PRESSURE RIDGING WEST THROUGH THE STRAITS BETWEEN THE
KEYS AND CUBA.

&&

.SHORT TERM (TODAY-TUESDAY)...
THE UPPER LEVEL RIDGING SHIFTS TO THE UPPER GREAT LAKES-LOWER
MISSISSIPPI VALLEY AS THE EASTERN TROUGH DIGS SOUTHWARD AND
SLIPS EAST...FORMING A CLOSED LOW OVER THE CAROLINAS BY TUE
AFTERNOON. AS A RESULT DEEP AND MOIST SOUTHWEST AND WEST FLOW
ALOFT CONTINUES OVER THE AREA...MODEL PWAT VALUES RUN IN THE 1.7
TO OVER 2 INCH RANGE...WITH THE HIGHEST AMOUNTS IN THE CENTRAL AND
SOUTHERN COUNTIES. THE EXTREME FAR NORTH REMAINS SLIGHTLY DRIER
WITH PWAT VALUES OF 1.5 TO 1.7 INCHES. THE SOUTHWEST AND WEST
FLOW ALOFT ALONG WITH STRENGTHENING OF THE ATLANTIC SURFACE RIDGE
TO THE SOUTH WILL HELP TO SLOWLY MOVE THE BOUNDARY ACROSS FL
NORTHWARD. MEANWHILE THE MID CONUS HIGH PRESSURE MOVES TO THE
NORTHEAST U.S. WITH THE COLD FRONT SAGGING INTO THE NORTHERN GULF
AND NORTHERN FL...WEAKENING SOME AS IT MERGES WITH THE NORTHWARD
CREEPING BOUNDARY. THE SURFACE HIGH BEGINS TO BRIDGE BOTH FEATURES
WITH A MORE ROBUST EASTERLY LOW LEVEL FLOW SPREADING ACROSS THE
AREA LATE TUE.

THE DEEP MOISTURE...UPPER LEVEL ENERGY...AND LOW LEVEL CONVERGENCE
ALONG THE BOUNDARY WILL SUPPORT CLOUDY SKIES WITH SHOWERS AND
THUNDERSTORMS IN THE ISOLATED TO NUMEROUS RANGE. THE GREATEST
COVERAGE WILL BE IN THE CENTRAL AND SOUTHERN COUNTIES WHERE THE
DEEPEST MOISTURE IS. SHOWERS AND STORMS WILL WIND DOWN OVERNIGHT ON
LAND WITH THE LOSS OF SOME DAYTIME HEATING...DESPITE THE CLOUD
COVER. THEY CONTINUE ON THE GULF WATERS OVERNIGHT THEN TRANSLATE
BACK ONSHORE TUE. TEMPERATURES WILL BE CLOSE TO NORMAL...WITH LOWS
ON THE WARM SIDE AND HIGHS ON THE COOLER SIDE.

.LONG TERM (TUESDAY NIGHT-MONDAY)...
MODELS IN FAIRLY GOOD AGREEMENT THROUGH SATURDAY. STALLED FRONTAL
BOUNDARY WILL REMAIN DRAPED ACROSS THE PENINSULA AS DEEP MOISTURE
AND UPPER ENERGY LINGER OVER THE STATE THROUGH SATURDAY. UPPER
RIDGING WILL THEN BUILD OVER THE STATE LATER SATURDAY WITH SOME
DRIER AIR MOVING INTO THE AREA. WEAK RIDGING WILL THEN BE IN PLACE
ACROSS THE AREA AS A TROUGH/AREA OF LOW PRESSURE DEVELOPS TO THE
NORTH OR WEST OF THE AREA FOR SUNDAY AND MONDAY. THE LOCATION OF
THIS DEVELOPING FEATURE IS QUITE DIFFERENT BETWEEN THE GFS AND ECMWF
AND WILL CONTINUE TO BE MONITORED OVER THE NEXT FEW DAYS. GENERALLY
EASTERLY FLOW WILL REMAIN IN PLACE ACROSS THE AREA THROUGH
SATURDAY...WITH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
POSSIBLE EACH DAY. WINDS ARE THEN EXPECTED TO TURN TO THE S/SE WITH
THE TROUGH IN PLACE TO THE NORTH OR WEST...BUT THIS WILL BE ADJUSTED
AS THE LOCATION OF THE TROUGH BECOMES BETTER RESOLVED. TEMPERATURES
WILL BE IN THE MID 80S TO NEAR 90 FOR HIGHS...AND IN THE UPPER 60S
TO MID 70S FOR LOWS EACH DAY.

&&

.AVIATION...
22/06Z-23/06Z. HAVE OPTED TO KEEP ALL TAFS VFR WITH VCSH IN THE
MORNING AND VCTS LATE MORNING INTO THE AFTERNOON. ANY MVFR TO LCL
IFR WOULD BE MOST LIKELY WITH THE TSRA LATER IN THE DAY. CALM TO
LIGHT VARIABLE WINDS BECOME SOUTH TO SW IN THE AFTERNOON.

&&

.MARINE...
A BOUNDARY ACROSS FL LIFTS NORTH AND MERGES WITH A SOUTHWARD MOVING
COLD FRONT OVER THE NEXT COUPLE OF DAYS...AS HIGH PRESSURE TRACKING
ACROSS THE EASTERN U.S. BRIDGES THE TWO FEATURES. THE FRONT/BOUNDARY
SETTLES SOUTH DOWN ACROSS THE STATE FOR MID TO LATE WEEK. WINDS
AND SEAS INCREASE SOME BUT NO HIGHER THAN 15 KNOTS AND 4 FEET.
SHOWERS AND THUNDERSTORMS WILL PRODUCE THE MAIN HAZARDS OF
LOCALLY HIGHER WINDS AND SEAS.

&&

.FIRE WEATHER...
NO CONCERNS FOR THE NEXT FEW DAYS AS RELATIVE HUMIDITY VALUES WILL
REMAIN ABOVE CRITICAL THRESHOLDS. WINDS INCREASE SOME TUE AND LATER
BUT WITH LITTLE IMPACT EXPECTED FOR THE FIRE WEATHER FORECAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  88  74  87  73 /  60  40  60  30
FMY  89  74  88  72 /  60  40  50  40
GIF  88  72  88  72 /  60  40  60  30
SRQ  87  73  86  73 /  60  40  60  40
BKV  88  68  88  68 /  60  40  60  30
SPG  86  75  86  75 /  60  40  60  30

&&

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

$$

SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WEATHER...09/RUDE
LONG TERM/DECISION SUPPORT...24/HUBBARD







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