Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
000
FXUS62 KTBW 020738
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
338 AM EDT THU OCT 2 2014

...MUCH DRIER AND COOLER WEATHER EXPECTED SUNDAY INTO EARLY
NEXT WEEK...

.SHORT TERM (TODAY - FRIDAY)...
A FRONTAL TROUGH WHICH HAS PERSISTED ACROSS THE SOUTH CENTRAL
PENINSULA THE LAST SEVERAL DAYS WILL FINALLY WASH OUT TODAY AS
MID LEVEL AND SURFACE RIDGING BUILDS IN OVER THE REGION THROUGH
TONIGHT. DRIER MID LEVEL AIR OVER THE REGION VIA WATER VAPOR LOOP
AND MODEL SOUNDING DATA IS SUPPORTING DRY CONDITIONS ACROSS THE
REGION EARLY THIS MORNING UNDER PARTLY CLOUDY SKIES. LIGHT WINDS
AND AMPLE GROUND MOISTURE MAY SUPPORT SOME SHALLOW PATCHY FOG OVER
INLAND LOCATIONS FROM POLK-HILLSBOROUGH COUNTIES NORTH INTO THE
NATURE COAST PRIOR TO SUNRISE...AND WILL INCLUDE A MENTION OF IN
THE GRIDS AND ZONES.

AS FOR THE REST OF TODAY AMPLE LOW LEVEL MOISTURE COUPLED WITH
DAYTIME HEATING...SEA BREEZE CONVERGENCE...AND A WEAK UPPER LEVEL
DISTURBANCE MOVING ACROSS THE REGION FROM THE GULF SHOULD SUPPORT
ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT DURING
THE AFTERNOON...WITH A WEST TO NORTHWEST STEERING FLOW FAVORING
HIGHEST RAIN CHANCES TO THE EAST OF THE I-75 CORRIDOR. MAV POPS LOOK
A BIT LOW TODAY...SO WILL LEAN CLOSER TO THE MET VALUES AND DEPICT
A 20 TO 30 PERCENT POP GRADIENT FROM THE COAST TO INLAND LOCATIONS.
WITH A BIT MORE SUNSHINE EXPECTED PRIOR TO THE ONSET OF THE
CONVECTION TEMPERATURES SHOULD BE ABLE TO CLIMB INTO THE UPPER 80S
TO AROUND 90 ALONG THE COAST...AND LOWER 90S INLAND.

TONIGHT ANY EVENING SHOWERS OR STORMS OVER INLAND LOCATIONS SHOULD
WIND DOWN AFTER SUNSET AS BOUNDARY INTERACTIONS WEAKEN AND LOSS OF
DAYTIME HEATING OCCURS WITH A PARTLY CLOUDY AND MAINLY DRY OVERNIGHT
PERIOD EXPECTED. SIMILAR TO THIS MORNING MAY AGAIN SEE SOME PATCHY
SHALLOW FOG DEVELOP OVER INLAND LOCATIONS PRIOR TO SUNRISE...AND
WILL AGAIN INCLUDE A MENTION OF IN THE GRIDS AND ZONES.

ON FRIDAY SURFACE AND MID LEVEL RIDGING WILL SHIFT EAST SOUTHEAST
DURING THE DAY AS AN AMPLIFYING UPPER TROUGH AND ATTENDANT COLD
FRONT MOVES INTO THE LOWER MISSISSIPPI VALLEY DURING THE AFTERNOON.
SIMILAR TO TODAY AMPLE MOISTURE (PW`S 1.7 TO 1.9 INCH RANGE)
COMBINED WITH DAYTIME HEATING WILL AGAIN SUPPORT ISOLATED TO
SCATTERED SHOWER AND STORM COVERAGE (POPS 20 TO 30 PERCENT RANGE
COAST TO INLAND) OVER THE FORECAST AREA WITH A WESTERLY STEERING
FLOW AGAIN FAVORING HIGHEST RAIN CHANCES OVER INLAND AND EASTERN
SECTIONS OF THE PENINSULA DURING THE AFTERNOON. TEMPERATURES ON
FRIDAY WILL BE SIMILAR TO TODAY WITH HIGHS AGAIN CLIMBING INTO THE
UPPER 80S TO AROUND 90 ALONG THE COAST...AND LOWER 90S INLAND.

.LONG TERM (FRIDAY NIGHT - WEDNESDAY)...
GFS AND ECMWF REMAIN IN REMARKABLY GOOD AGREEMENT OVER A STRONG COLD
FRONT THAT IS FORECAST TO MOVE THROUGH THE AREA THIS WEEKEND. FRIDAY
NIGHT...A DEEP UPPER/MID LEVEL TROUGH WILL BE SWINGING INTO THE
UPPER MIDWEST WITH THE ASSOCIATED SURFACE LOW CENTERED NORTH OF THE
GREAT LAKES. OF SIGNIFICANCE TO THE FLORIDA PENINSULA...THIS SURFACE
LOW WILL BE SWEEPING A VIGOROUS COLD FRONT THROUGH THE SOUTHEASTERN
CONUS...WHICH BY FRIDAY EVENING...IS FORECAST TO HAVE REACHED THE
FLORIDA PANHANDLE. THIS FRONT WILL THEN QUICKLY PASS THROUGH THE
FORECAST AREA...AND IS FORECAST TO REACH THE NATURE COAST
BEFORE SUNRISE SATURDAY MORNING...AND SHOULD CLEAR THE STATE BY
SATURDAY EVENING. MOISTURE AHEAD OF THE FRONTAL PASSAGE IS STILL
PLENTIFUL...SO WITH THE ADDED INSTABILITY AND LIFT COMING FROM THE
COLD FRONT...THE ENTIRE AREA WILL SEE A PRETTY GOOD SHOT AT
SHOWERS AND THUNDERSTORMS BEGINNING LATE FRIDAY NIGHT. THE AIRMASS
BEHIND THE COLD FRONT WILL BE THE DRIEST THIS AREA HAS SEEN SINCE
THE SPRING...WITH GFS FORECAST PRECIPITABLE WATER VALUES DROPPING
FROM AROUND 2 INCHES AHEAD OF THE FRONT...TO AS LOW AS 0.3 INCHES
BEHIND THE FRONT. AS A RESULT...RAIN CHANCES SHOULD BEGIN CLEARING
OUT OF THE NATURE COAST BY MID MORNING SATURDAY...AND WILL BE OUT OF
ENTIRE AREA BY SATURDAY EVENING.

BEHIND THE FRONT...THE COOLEST AND DRIEST AIR MASS SINCE SPRING WILL
SETTLE INTO THE REGION...WITH LOW TEMPERATURES EXPECTED TO DROP INTO
THE 50S AND LOW 60S SATURDAY AND SUNDAY NIGHT...AND HIGHS SUNDAY
ONLY REACHING THE UPPER 70S TO LOW 80S. AS STRONG SURFACE HIGH
PRESSURE BUILDS INTO NORTHERN FLORIDA...RAIN CHANCES WILL BE MINIMAL
THROUGH MONDAY. A MID LEVEL SHORTWAVE TROUGH WILL THEN MOVE INTO
FLORIDA FROM THE GULF ON MONDAY NIGHT AND TUESDAY...BRINGING ANOTHER
CHANCE FOR SHOWERS AND THUNDERSTORMS...WITH THE HIGHEST CHANCES ON
TUESDAY AFTERNOON.

&&

.AVIATION...
A LIGHT NORTHEAST WIND FLOW COMBINED WITH AMPLE LOW LEVEL MOISTURE
MAY SUPPORT SOME MVFR/IFR LOW CLOUDS AT THE TERMINALS THROUGH 12Z
THIS MORNING...HOWEVER OVERALL CONFIDENCE IN THIS IS LOW...SO HAVE
ONLY DEPICT FEW/SCT010 FOR NOW...BUT BRIEF TEMPO MVFR/IFR CIGS MAY
BECOME NECESSARY IN ANY AMENDMENTS LATER THIS MORNING SHOULD COVERAGE
OF LOW CLOUDS INCREASE MORE THAN CURRENTLY EXPECTED. ANY LOW CLOUDS
THAT FORM WILL BURN OFF AFTER 12Z WITH MAINLY VFR EXPECTED THROUGH
18Z. AFTER 18Z SHRA/TSRA WILL DEVELOP OVER THE REGION AND HAVE
HANDLED WITH VCTS FOR NOW...OTHERWISE VFR WILL CONTINUE. NORTHEAST
WINDS AOB 5 KNOTS THIS MORNING WILL BECOME WEST TO NORTHWEST AT 6
TO 8 KNOTS AFTER 18Z AS THE SEA BREEZE DEVELOPS AND MOVES INLAND.

&&

.MARINE...
A FRONTAL TROUGH ACROSS THE SOUTH CENTRAL PENINSULA EARLY THIS MORNING
WILL WASH OUT DURING THE DAY AS SURFACE AND MID LEVEL RIDGING BUILDS
IN OVER THE REGION. A LIGHT NORTHEAST TO EASTERLY WIND FLOW CAN BE
EXPECTED TODAY ALONG WITH SEAS LESS THAN 2 FEET WITH AN ONSHORE SEA
BREEZE COMPONENT DEVELOPING ALONG THE COAST DURING THE AFTERNOON.
TONIGHT THE SURFACE HIGH WILL SLOWLY SHIFT EAST AND SOUTHEAST AS AN
AMPLIFYING UPPER TROUGH AND ATTENDANT COLD FRONT MOVES INTO THE LOWER
MISSISSIPPI VALLEY. AS THE HIGH SHIFT EAST WINDS WILL VEER AROUND TO
THE SOUTHEAST AND SOUTH THROUGH FRIDAY MORNING...THEN BECOMING SOUTHWEST
FRIDAY AFTERNOON AS THE COLD FRONT MOVES INTO THE WESTERN FLORIDA
PANHANDLE.

DURING FRIDAY NIGHT INTO SATURDAY SOUTHWEST WINDS WILL INCREASE TOWARD
EXERCISE CAUTION LEVELS (15 TO 20 KNOTS) AS THE GRADIENT TIGHTENS AHEAD
OF THE APPROACHING COLD FRONT ALONG WITH BUILDING SEAS. WINDS WILL
SHIFT INTO THE NORTHWEST AND NORTH WITH SPEEDS POSSIBLY INCREASING
TOWARD ADVISORY LEVELS SATURDAY NIGHT INTO EARLY SUNDAY AS THE COLD
FRONT SWEEPS SOUTH THROUGH THE WATERS WITH SOME ROUGH BOATING
CONDITIONS DEVELOPING. WINDS AND SEAS WILL SLOWLY DIMINISH AND
SUBSIDE ON SUNDAY AS WINDS VEER INTO THE NORTHEAST AS SURFACE HIGH
PRESSURE BUILDS IN OVER THE NORTHERN GULF IN THE WAKE OF THE FRONT.
NORTHEAST TO EAST WINDS AROUND 10 KNOTS CAN BE EXPECTED OVER THE
WATERS EARLY NEXT WEEK AS SURFACE HIGH PRESSURE ALIGNS ITSELF FROM
THE MID ATLANTIC REGION SOUTHWEST TO THE NORTHERN GULF.

&&

.FIRE WEATHER...
AMPLE LOW LEVEL MOISTURE AND RAIN CHANCES WILL KEEP HUMIDITY VALUES
WELL ABOVE CRITICAL LEVELS THROUGH THE END OF THE WEEK AND INTO THE
START OF THE UPCOMING WEEKEND WITH NO FIRE WEATHER ISSUES EXPECTED.
DURING SATURDAY NIGHT A MUCH DRIER AND COOLER AIR MASS WILL ADVECT
INTO THE REGION ON A BREEZY NORTHWEST TO NORTHERLY WIND FLOW IN THE
WAKE OF A STRONG COLD FRONT. THIS MUCH DRIER AIR MASS WILL ALLOW
HUMIDITY VALUES TO FALL BELOW 35 PERCENT FOR A FEW HOURS FROM
HILLSBOROUGH POLK COUNTIES NORTH INTO THE NATURE COAST SUNDAY
AFTERNOON. DESPITE THESE LOW HUMIDITY VALUES THOUGH LOW ERC VALUES
COMBINED WITH LIGHTER WINDS SHOULD PRECLUDE RED FLAG CONDITIONS.
A SLOW INCREASE IN MOISTURE WILL BRING HUMIDITY VALUES BACK ABOVE
CRITICAL LEVELS EARLY NEXT WEEK AS A NORTHEAST TO EAST WIND FLOW
DEVELOPS OVER THE REGION.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  88  74  88  76 /  20  10  20  40
FMY  91  74  90  75 /  20  10  30  30
GIF  90  72  91  73 /  30  20  30  30
SRQ  87  73  88  76 /  20  10  20  40
BKV  88  70  88  72 /  20  10  30  50
SPG  89  77  89  77 /  20  10  20  40

&&

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

$$

SHORT TERM/AVIATION/MARINE/FIRE WEATHER...57/MCMICHAEL
LONG TERM/DECISION SUPPORT...18/FLEMING






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.