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000
AXNT20 KNHC 141757
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE MAY 14 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
1745 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA-BISSAU NEAR
12N16W TO 9N21W. THE ITCZ BEGINS FROM 9N21W AND CONTINUES
THROUGH 04N30W TO 03N40W TO 01N53W. SCATTERED MODERATE
CONVECTION IS WITHIN 150 NM SOUTH OF THE AXIS BETWEEN 26W-
32W...AND ALSO WITHIN 210 NM N OF THE AXIS BETWEEN 38W-43W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 180 NM N OF THE
ITCZ AXIS W OF 47W.

...DISCUSSION...

GULF OF MEXICO...
A 1025 MB HIGH CENTER IS LOCATED OVER SE LOUISIANA AS OF 1500
UTC WITH ASSOCIATED RIDGING BUILDING E ACROSS THE AREA. THE
PREVIOUS MENTIONED COLD FRONT OVER THE SE AND S PORTIONS OF THE
GULF WITH STATIONARY FRONT OVER THE SW GULF IS DISSIPATING AS
THE RIDGE BUILDS ACROSS THE AREA. BUOY AND SURFACE OBSERVATIONS
DEPICT GENERALLY ANTI-CYCLONIC FLOW N OF THE DECAYING FRONTAL
BOUNDARY. A SURFACE TROUGH IS IN THE SW GULF AND EASTERN BAY OF
CAMPECHE ROUGHLY ALONG 93W S OF 22N. WIDELY SCATTERED SHOWERS ARE
POSSIBLE WITHIN 120 NM W AND 60 NM E OF THE TROUGH. SCATTERED TO
BROKEN LOW CLOUDS WITH ISOLATED SHOWERS ARE ELSEWHERE W OF THE
TROUGH...AND ALSO FROM 22N TO 28N W OF 93W. OVER THE REMAINDER
OF THE GULF...LATEST VIS SATELLITE IMAGERY SHOWS MOSTLY CLEAR
SKIES UNDER THE AFOREMENTIONED HIGH PRES ALONG WITH DRY AIR
ALOFT AS SEEN IN WATER VAPOR IMAGERY. WATER VAPOR IMAGERY ALSO
SHOWS UPPER LEVEL RIDGING OVER THE WESTERN AND CENTRAL GULF
PORTIONS...WHILE A DEEP LAYER TROUGH IS NOTED OVER THE W
ATLANTIC. THE FLOW PATTERN BETWEEN THESE FEATURES IS NWLY
...EXCEPT W-NW ACROSS THE UPPER RIDGE. THE RIDGE IS FORECAST TO
SHIFT E OF THE AREA BY THU WITH ZONAL FLOW SETTING UP ACROSS THE
AREA. THE SURFACE COLD FRONT WILL CONTINUE TO DISSIPATE THROUGH
EARLY WED AS IT SLOWLY MOVES S TOWARDS CUBA...AND AS HIGH PRES
RIDGING EXTENDS E TO W OVER THE FAR NORTHERN GULF. THE TROUGH
ALONG 93W WILL WEAKEN THROUGH WED EVENING AS IT MOVES INLAND
MEXICO.

CARIBBEAN SEA...
VERY WELL PRONOUNCED HIGH PRES IN THE UPPER LEVELS OF THE
ATMOSPHERE THROUGHOUT THE CARIBBEAN CONTINUES TO RESULT IN
MODERATE SUBSIDENCE DRY AND DRY CONDITIONS ALOFT. AN UPPER LEVEL
TROUGH IS JUST E OF THE CARIBBEAN. AS A RESULT...DEEP LAYER
MOISTURE REMAINS VERY SUPPRESSED ACROSS THE AREA WITH ONLY
ISOLATED SHOWERS MOVING TO THE WNW N OF 14N E OF 72W...AND
SIMILAR SHOWERS MOVING SW TO THE N OF 14N W OF 79W. MORE
CONCENTRATED MOISTURE IS EVIDENT OVER HAITI AND OVER PORTIONS OF
THE DOMINICAN REPUBLIC WHERE A SURFACE TROUGH EXISTS. THIS
MOISTURE SHOULD COMBINE WITH AFTERNOON HEATING TO PRODUCE
SCATTERED SHOWERS AND TSTMS ACROSS MUCH OF HISPANIOLA FOR THE
REST OF TODAY...AND AGAIN WED AND THU AS ADDITIONAL MOISTURE
ASSOCIATED WITH THE TAIL END OF THE WEAKENING WESTERN ATLC COLD
FRONT APPROACHES EASTERN CUBA AND HISPANIOLA. ELSEWHERE LITTLE
OVERALL CHANGE IS EXPECTED.

ATLANTIC OCEAN...
WATER VAPOR IMAGERY SHOWS A DEEP LAYER TROUGH EXTENDING FROM
32N70W SW TO NEAR 24N79W. THE TROUGH SUPPORTS A SURFACE COLD
FRONT THAT STRETCHES FROM NEAR 32N66W SW TO 26N73W TO ANDROS
ISLANDS WHERE IT BEGINS TO DISSIPATE TO THE STRAITS OF FLORIDA.
A PRE-FRONTAL SURFACE TROUGH IS EAST OF THE FRONT FROM 32N65W TO
23N78W. ANOTHER SURFACE TROUGH IS ROUGHLY ALONG 70W S OF 23N TO
ACROSS THE CENTRAL PORTION OF THE DOMINICAN REPUBLIC. SCATTERED
SHOWERS AND THUNDERSTORMS ARE WITHIN 240 NM E OF THE PRE-FRONTAL
TROUGH N OF 26N...WHILE SCATTERED SHOWERS AND ISOLATED TSTMS ARE
ELSEWHERE WITHIN 210 NM E OF THE TROUGH. A RIDGE/TROUGH/RIDGE
PATTERN REMAINS OVER THE REMAINDER OF THE UPPER LEVELS ACROSS
THE BASIN. THE FIRST UPPER RIDGE EXTENDS FROM ABOUT 32N55W SSW
TO 25N57W TO 18N58W. THE UPPER TROUGH IS CONNECTED TO AN UPPER
LEVEL LOW N OF THE AREA NEAR 32N42W MOVING SW...AND STRETCHES
THROUGH 25N47W AND FURTHER SW TO JUST E OF THE WINDWARD ISLANDS
NEAR 10N60W. THE SECOND UPPER RIDGE IS BROAD AND COVERS THE
MAJORITY OF THE TROPICAL ATLC...AND IS CENTERED NEAR 12N23W. AT
THE SURFACE...A TROUGH INDUCED BY THE UPPER LEVEL LOW LIES ALONG
29N41W 24N44W. DIVERGENCE ALOFT E OF THE UPPER LOW IN
COMBINATION WITH THE SURFACE TROUGH IS HELPING TO SET OFF DEEP
LAYER MOISTURE WITH SCATTERED SHOWERS AND ISOLATED TSTMS FROM
25N TO 31N BETWEEN 30W-42W. ELSEWHERE ACROSS THE AREA...HIGH
PRESSURE THROUGH ALL LEVELS OF THE ATMOSPHERE IS MAINTAINING
GENERALLY FAIR CONDITIONS. SCATTERED SHOWERS ARE ALONG AND NEAR
THE TROUGH THAT IS ALONG 70W.

THE COLD FRONT MENTIONED ABOVE IS FORECAST TO WEAKEN AND SHEAR
OFF W OF ABOUT 65W AS IT PUSHES EASTWARD THROUGH THU...WITH
LINGERING MOISTURE TO BE AROUND THE VICINITY OF EASTERN
CUBA...THE SE BAHAMAS AND COMBINING WITH THAT ALREADY IN PLACE
OVER HISPANIOLA.

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.

$$
AGUIRRE