[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 071807
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE MAY 07 2013

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF GAMBIA NEAR 12N16W
TO 7N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
7N20W TO 2N30W WHERE IT STRADDLES THE EQUATOR TO ALONG 42W.
SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 180 NM N OF
THE ITCZ BETWEEN 28W AND 37W. WIDELY SCATTERED MODERATE
CONVECTION IS ALONG THE ITCZ TO THE EQUATOR BETWEEN 20W AND 40W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS ALSO NOTED
WELL S OF THE MONSOON TROUGH FROM 2N-4N BETWEEN 8W-12W.

...DISCUSSION...

GULF OF MEXICO...

AS OF 1500 UTC... A 1020 MB HIGH IS OVER THE NW GULF OF MEXICO
NEAR 26N92W. LIGHT AND VARIABLE SURFACE WINDS OF 5 TO 10 KT ARE
NOTED OVER MOST OF THE GULF ASSOCIATED WITH THE HIGH. THESE
WINDS RESULTED IN SEAS OF ONLY 1-2 FT OVER THE GULF. BROKEN TO
OVERCAST LOW CLOUDS REMAIN OVER THE FAR SW GULF AND BAY OF
CAMPECHE WITHIN A 180 NM RADIUS OF VERACRUZ MEXICO. A
CONCENTRATED LINE OF LOW AND MID LEVEL CLOUDS EXTENDING FROM THE
FLORIDA COAST NEAR CEDAR KEY TO 28.5N86.5W MARKED THE TRAILING
END OF A SURFACE TROUGH WHICH EXTENDED FROM A DEEP LAYERED
CYCLONE OVER NE GEORGIA. NATIONAL COMPOSITE RADAR IMAGERY SHOWS
WEAKENING SCATTERED SHOWERS WITHIN 15 NM OF THE TROUGH.
ELSEWHERE CLEAR SKIES WITH A FEW PATCHES OF CUMULIFORM CLOUDS
WERE NOTED. IN THE UPPER LEVELS...A LARGE DEEP LAYERED CYCLONE
IS CENTERED OVER EXTREME NE GEORGIA AND NW SOUTH CAROLINA WITH
MODERATE TO STRONG UPPER LEVEL WESTERLY WINDS AND SUBSIDENCE
OVER FLORIDA. HIGH PRESSURE IS FORECAST TO MOVE EASTWARD OVER
THE NEXT 48 HOURS WITH RETURN SE FLOW SPREADING E OVER THE GULF.

CARIBBEAN SEA...

A SURFACE TROUGH EXTENDS FROM S OF HISPANIOLA NEAR 17N71W TO NW
VENEZUELA NEAR 12N72W. WIDELY SCATTERED SHOWERS ARE WITHIN 120
NM OF THE TROUGH N OF 15N. A MORE CONCENTRATED AREA OF SHOWERS
AND THUNDERSTORMS WAS OVER THE NE CARIBBEAN N OF 16N E OF 70W
SPREADING NW OVER PUERTO RICO AND TOWARD THE DOMINICAN REPUBLIC.
ADDITIONALLY...SCATTERED SHOWERS AND ISOLATED MODERATE
CONVECTION WAS OVER VENEZUELA AND COLOMBIA FROM 2N-7N BETWEEN
66W-76W. TRADE WINDS OVER THE CARIBBEAN WERE LIGHTER THAN NORMAL
WITH MOST OF THE AREA EXPERIENCING WINDS AROUND 10 KT...A FEW
AREAS IN THE CARIBBEAN E OF THE TROUGH AXIS REPORTED E TO SE
WINDS OF 15 KT. TRADEWINDS TURNED MORE NORTHERLY W OF THE TROUGH
AXIS...BUT REMAINED LIGHT. IN THE UPPER LEVELS...THE WESTERN
PORTION OF AN UPPER LEVEL HIGH IS PRODUCING SW UPPER LEVEL FLOW
OVER THE CARIBBEAN SEA WITH STRONG SUBSIDENCE OVER THE W
CARIBBEAN W OF 72W AND SIGNIFICANT UPPER LEVEL MOISTURE AND
BROKEN HIGH CLOUD OVER THE E CARIBBEAN. THE SURFACE TROUGH IS
FORECAST TO WEAKEN OVER THE NEXT 48 HOURS AS IT TRACKS TO THE W.
A MORE NORMAL TRADE WIND REGIME IS FORECAST TO DEVELOP WITH 15
TO 20 KT WINDS EXPANDING ACROSS THE CENTRAL CARIBBEAN BETWEEN
70W AND 78W.

ATLANTIC OCEAN...

AS OF 1500 UTC...A COLD FRONT EXTENDED INTO THE AREA THROUGH
32N75W TO ANDROS ISLAND IN THE BAHAMAS. TO THE EAST...A WARM
FRONT EXTENDED FROM 32N71W TO NE OF THE BAHAMAS NEAR 26N65W.
SCATTERED SHOWERS AND THUNDERSTORMS WERE WITHIN 180 NM NE OF THE
WARM FRONT. FURTHER E...A STATIONARY 1012 MB LOW IS CENTERED
OVER THE CENTRAL ATLANTIC NEAR 33N39W. A SURFACE TROUGH EXTENDS
FROM THE LOW THROUGH 31N36W TO 26N40W. THE LEADING COLD FRONT
EXTENDED FROM 32N25W TO 26N30W TO 22N37W...WHERE IT BECAME A
DISSIPATING FRONT/SHEAR LINE THROUGH 20N45W TO JUST NE OF THE
LEEWARD ISLANDS NEAR 19N62W. WIDELY SCATTERED SHOWERS ARE WITHIN
180 NM SE OF THE COLD FRONT N OF 28N...AND WITHIN 90 NM OF THE
FRONT ELSEWHERE E OF 40W. IN THE UPPER LEVELS...MOSTLY ZONAL
FLOW IS N OF 20N BETWEEN 50W-80W. FURTHER E...A BROAD TROUGH N
OF 25N EXTENDED BETWEEN 30W AND 50W WITH AN EMBEDDED DEEP
LAYERED CYCLONE NEAR 32N38W. AN UPPER LEVEL TROUGH IS OVER THE E
ATLANTIC E OF 30W. THE OCCLUDED FRONTAL SYSTEMS OVER THE NW ATLC
ARE FORECAST TO MOVE SLOWLY E...WHILE THE CENTRAL ATLANTIC COLD
FRONT MOVES STEADILY E WITH SHOWERS AND CONVECTION WANING AS
UPPER LEVEL SUPPORT WEAKENS.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

AT THE REQUEST OF METEO-FRANCE AND THE METEOROLOGICAL SERVICES OF
HAITI AND THE DOMINICAN REPUBLIC...THE TROPICAL ANALYSIS AND
FORECAST BRANCH (TAFB) WILL BEGIN PROVIDING...ON A TEMPORARY
BASIS...A SEPARATE DETAILED SECTION WITHIN THE ATLANTIC TROPICAL
WEATHER DISCUSSION (TWDAT). IT WILL COVER BOTH HAITI AND THE
DOMINICAN REPUBLIC DUE TO THE SHARED GEOGRAPHY OF BOTH COUNTRIES
ON THE ISLAND OF HISPANIOLA.

THE SECTION BEGINS ON MAY 15 2013 AT 1800 UTC...2 PM EDT. IT
WILL PROVIDE GUIDANCE FOR SIGNIFICANT WEATHER EVENTS THAT ARE
EXPECTED TO IMPACT THE REGION THROUGH 48 HOURS...WITH THE FOCUS
ON ASSESSING THE POTENTIAL FOR HEAVY RAINFALL.

$$
COBB


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