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000
FXUS62 KTBW 250819
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
419 AM EDT SAT MAY 25 2013

.SHORT TERM (TODAY THROUGH MONDAY)...
CURRENTLY AT THE SURFACE...A LARGE ELONGATED RIDGE OF HIGH PRESSURE
EXTENDS FROM NORTHERN CANADA...SOUTHWARD INTO THE NORTHERN GULF OF
MEXICO. MEANWHILE...THE WEAKENING FRONTAL BOUNDARY WHICH PUSHED
THROUGH THE AREA YESTERDAY NOW RESIDES ACROSS FAR SOUTH FLORIDA.
INFRARED SATELLITE IMAGERY SHOWS CLEAR TO PARTLY CLOUDY SKIES IN
PLACE ACROSS THE FORECAST AREA...WITH RADAR IMAGERY INDICATING A FEW
SHOWERS AND THUNDERSTORM SINKING SOUTHWARD ALONG THE SOUTHEAST
FLORIDA COAST. MAIN SHORT TERM CONCERNS FOR TODAY REVOLVE AROUND
FIRE WEATHER AND MARINE ISSUES...ADDRESSED IN THE SECTIONS BELOW.

TODAY...
STRONG HIGH PRESSURE WILL CONTINUE TO BUILD NORTH OF THE
STATE...ALLOWING THE DRIER AIRMASS CURRENTLY SEEN IN SURFACE
OBSERVATIONS ACROSS NORTHERN FLORIDA TO PUSH SOUTHWARD AND INTO
THE FORECAST AREA. LATEST CONVECTION ALLOWING MODEL GUIDANCE
SUGGESTS THE POTENTIAL FOR A FEW ISOLATED SHOWERS OR STORMS TO
DEVELOP AFTER 18Z THIS AFTERNOON ALONG THE BOUNDARY OF HIGHER
DEWPOINT AIR WHICH WILL BE PUSHING THROUGH CENTRAL AND SOUTHERN
ZONES. THE BEST CHANCE FOR AN ISOLATED SHOWER OR STORM WILL BE
SOUTH OF INTERSTATE 4...BUT COVERAGE IF ANY SHOWERS/STORMS MANAGE
TO DEVELOP SHOULD BE QUITE LOW GIVEN THE DRY MID-LEVEL AIR
ADVECTING INTO THE AREA. AS A RESULT...WILL CAP POPS AT 10 PERCENT
AND NOT MENTION IN THE FORECAST. HIGH TEMPERATURES ARE EXPECTED TO
TOP OUT IN THE UPPER 80S TO LOWER 90S.

TONIGHT...
HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE...WITH MOSTLY
CLEAR SKIES AND COOLER TEMPERATURES ANTICIPATED. OVERNIGHT LOWS WILL
BOTTOM OUT IN THE MID TO UPPER 50S ACROSS THE NATURE COAST...AND
AROUND 60 TO THE MID 60S FOR CENTRAL AND SOUTHERN ZONES AWAY FROM
THE IMMEDIATE COAST.

SUNDAY THROUGH MONDAY...
A RIDGE OF HIGH PRESSURE WILL DOMINATE WEATHER OVER THE SOUTHEAST
UNITED STATES TO CLOSE THE MEMORIAL DAY WEEKEND. MINIMAL RAIN
CHANCES...SUNNY SKIES...AND EASTERLY FLOW WILL BE FORECAST FEATURES
FOR THE HOLIDAY WEEKEND.

PORTIONS OF SOUTHWEST FLORIDA MAY SEE SUFFICIENT MOISTURE RETURN ON
MONDAY AFTERNOON TO SEE A SLIGHT CHANCE FOR SHOWERS AND POSSIBLY
THUNDERSTORMS. WHILE MODEL TRENDS SHOW THE INCREASING RAIN CHANCES
IN SWFL...THE 00Z NAM HAS THIRTY POPS WHILE THE 00Z GFS IS IN THE
MID-TEENS. INCREASING INSTABILITY...WITH SWFL MUCAPE VALUES
EXCEEDING 1000 J/KG IN THE 00Z GFS AND NEARLY 2000 J/KG VALUES IN
THE 00Z NAM...COULD WORK WITH AVAILABLE MOISTURE TO CREATE SOME
SHOWERS AND THUNDERSTORMS SOUTH OF CHARLOTTE HARBOR ON MONDAY
AFTERNOON.

MAXIMUM TEMPERATURES SHOULD STAY WITHIN A FEW DEGREES OF NORMAL THIS
WEEKEND. THE DRIER AIR IS AIDING TO KEEP MINIMUM TEMPERATURES ALMOST
5 TO 10 DEGREES BELOW NORMAL ACROSS THE AREA. WHILE THE DAYS
CERTAINLY FEEL MORE LIKE SUMMER...THE COOLER OVERNIGHTS ARE A
RESPITE OF SPRING.

&&

.LONG TERM (TUESDAY THROUGH SATURDAY)...
AN ATLANTIC RIDGE OF HIGH PRESSURE CONTINUES INTO THE BEGINNING OF
THE LONG TERM PERIOD. ATLANTIC MOISTURE WILL CROSS THE PENINSULA OF
FLORIDA ON THE EASTERLY FLOW...ALLOWING FOR INCREASING RAIN CHANCES.
LATE WEDNESDAY INTO THURSDAY...MODEL GUIDANCE HINTS AT A 500 MB LOW
DEVELOPING BETWEEN SOUTH FLORIDA AND THE BAHAMAS. THIS INTRODUCES
QUITE A BIT OF UNCERTAINTY TO END OF THE EXTENDED FORECAST PERIOD AS
MAJOR QUESTIONS REMAIN AS TO THE LOCATION...TIMING...AND EVEN THE
DEVELOPMENT OF THIS LOW.

WHILE THE START OF THE HURRICANE SEASON KNOCKS ON THE DOOR OF THE
EXTENDED PERIOD...IT MAY BE A TAD TOO EARLY TO EXPECT THIS LOW TO BE
TROPICAL IN NATURE. GUIDANCE ALSO DOES NOT OFFER MUCH IN THE WAY OF
A SURFACE LOW...WITH THE 12Z ECMWF SHOWING A SURFACE LOW IN THE GULF
VERTICALLY DISPLACED FROM THE 500 MB LOW. FORECAST UNCERTAINTY AT
THE MOMENT POINTS TOWARDS A NEED TO MONITOR THESE DEVELOPMENTS AS WE
GO THROUGH THE NEXT WEEK. THESE AREAS OF LOW PRESSURE COULD
DEFINITELY BRING AN UPSWING TO THE RAIN CHANCES NEXT WEEKEND.

MUCH LIKE THE SHORT TERM...TEMPERATURES DURING THE DAY WILL HOVER
NEAR NORMAL WHILE THE OVERNIGHTS WILL RECOVER AND STAY CLOSER TO
NORMAL BY THE END OF THE EXTENDED. OF COURSE...CLOUD COVER AND THE
LOW PRESSURE SYSTEM HINTED AT TO END THE PERIOD COULD AFFECT
TEMPERATURES BY A FEW DEGREES.

&&

.AVIATION...
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF FORECAST PERIOD. EXPECT
SOME GUSTINESS AT THE TAF SITES TODAY AS STRONG HIGH PRESSURE BUILDS
NORTH OF THE STATE.

&&

.MARINE...
TODAY AND TONIGHT...
STRONG HIGH PRESSURE WILL BUILD NORTH OF THE FORECAST
AREA...RESULTING IN ELEVATED EASTERLY WINDS ACROSS THE MARINE AREA.
WINDS SHOULD HOLD BELOW HEADLINE THRESHOLDS TODAY...BUT EXPECT A
PRETTY GOOD SURGE IN EASTERLY WINDS TO ARRIVE THIS EVENING...WITH
EXERCISE CAUTION OR ADVISORY LEVEL WINDS EXPECTED ACROSS ALL WATERS.

SUNDAY THROUGH FRIDAY...
EASTERLY FLOW CONTINUES THROUGH MUCH OF THE WEEK THANKS TO A
RIDGE OF HIGH PRESSURE DOMINATING THE WATERS. EAST WINDS BRING
SEAS TO SCEC...AND POSSIBLY SCA...CRITERIA MOSTLY IN THE OVERNIGHT
PERIODS THIS WEEK. WINDS AND WAVES SHOULD DECREASE BELOW SCEC/SCA
CRITERIA EVERY MORNING AFTER SUNRISE.

&&

.FIRE WEATHER...
TODAY AND TONIGHT...
STRONG HIGH PRESSURE WILL BUILD NORTH OF THE STATE TODAY RESULTING
IN AN ELEVATED EASTERLY FLOW ACROSS THE PENINSULA. THIS COMBINED
WITH HUMIDITY LEVELS DROPPING TO CRITICAL LEVELS WILL RESULT IN
ELEVATED FIRE DANGER ACROSS THE FORECAST AREA. TOUGH CALL ON RED
FLAG WARNING DECISIONS ACROSS THE AREA...BUT IT DOES APPEAR THAT
CENTRAL ZONES WILL HAVE A FAIRLY GOOD SHOT AT REACHING INSTANTANEOUS
RED FLAG CRITERIA WITH HUMIDITY LEVELS AT OR BELOW 35
PERCENT...SUSTAINED WINDS 15 MPH OR GREATER AND ENERGY RELEASE
COMPONENT VALUES OF 27 OR GREATER. AS A RESULT...WILL UPGRADE THE
FIRE WEATHER WATCH TO A RED FLAG WARNING FOR PORTIONS OF THE
FORECAST AREA AND CANCEL THE WATCH IN OTHER AREAS WHERE RED FLAG
CONDITIONS ARE NO LONGER EXPECTED.

SUNDAY THROUGH FRIDAY...
A RIDGE OF HIGH PRESSURE OVER WEST CENTRAL AND SOUTHWEST FLORIDA
WILL KEEP AN EASTERLY FLOW CONDUCIVE TO CREATE FIRE WEATHER
CONCERNS. CONDITIONS SHOULD BE MONITORED DAILY FOR THE LATEST ERC
VALUES. MOIST AIR SHOULD BEGIN TO INFILTRATE THE PENINSULA ON
MONDAY AND WITH INCREASING RAIN CHANCES SHOULD HOPEFULLY COME
DECREASING FIRE WEATHER CONCERNS AS THE WEEK CONTINUES.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  91  67  88  67 /   0   0   0   0
FMY  92  66  88  66 /  10   0  10  10
GIF  90  64  87  64 /  10   0   0   0
SRQ  92  65  88  66 /  10   0   0  10
BKV  90  57  88  60 /   0   0   0   0
SPG  89  72  86  71 /   0   0   0   0

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...RED FLAG WARNING FROM NOON TODAY TO 8 PM EDT THIS EVENING
     FOR DESOTO-HARDEE-HILLSBOROUGH-MANATEE-POLK-SARASOTA.

GULF WATERS...NONE.

&&

$$

SHORT TERM/MARINE/FIRE WEATHER...JELSEMA
LONG TERM/AVIATION...GARCIA