Tropical Weather Discussion
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000
AXNT20 KNHC 301746
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU APR 30 2015

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 AFRICAN COAST NEAR 09N13W TO
06N16W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
06N16W TO 01N28W TO 03N39W TO THE EQUATOR NEAR 50W. SCATTERED
MODERATE CONVECTION IS WITHIN 90 NM EITHER SIDE OF A LINE FROM
04N19W TO 04N40W TO 01N51W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR
IMAGERY OVER THE CAROLINAS WITH THE PARENT MIDDLE TO UPPER LEVEL
LOW CENTERED OVER THE GREAT LAKES REGION. THE SHORTWAVE TROUGH
SUPPORTS A BROAD AREA OF LOW PRESSURE ACROSS THE SW NORTH ATLC
AREA FOCUSED ON A 1003 MB LOW CENTERED NEAR 31N77W. THE
ASSOCIATED COLD FRONT EXTENDS FROM THE LOW CENTER TO THE
SOUTHERN FLORIDA PENINSULA TO THE LOWER FLORIDA KEYS TO ACROSS
THE CENTRAL YUCATAN PENINSULA. SOUTHWESTERLY FLOW PREVAILS ALOFT
OVER THE GULF WITH PLENTY OF MIDDLE TO UPPER LEVEL MOISTURE AND
CLOUDINESS COVERING THE GULF GENERALLY S OF 28N. A WEAKER
SECONDARY WAVE OF ENERGY IS ANALYZED AS A SURFACE TROUGH
EXTENDING FROM THE TAMPA BAY REGION W-SW TO 26N93W WITH A DRIER
AND MORE STABLE AIRMASS TO ITS NORTH. OTHERWISE...A RIDGE
ANCHORED BY A 1019 MB HIGH CENTERED NEAR TUXPAN MEXICO IS
PROVIDING MUCH OF THE GULF WITH GENTLE TO MODERATE NORTHERLY
BREEZE CONDITIONS WHICH ARE EXPECTED TO PERSIST ON THE EASTERN
PERIPHERY OF THE RIDGE THROUGH SATURDAY.

CARIBBEAN SEA...
WATER VAPOR IMAGERY INDICATES MUCH OF THE CARIBBEAN BASIN IS
UNDER THE INFLUENCE OF DRY AND STABLE FLOW ALOFT ASSOCIATED WITH
AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 18N67W. THE ANTICYCLONE
IS PROVIDING FOR OVERALL MOSTLY CLEAR SKIES AND FAIR CONDITIONS
THIS AFTERNOON GENERALLY E OF 78W. W OF 78W...ON THE FAR WESTERN
PERIPHERY OF THE UPPER LEVEL RIDGING...MID-LEVEL MOISTURE
INCREASES AS SOUTHWESTERLY FLOW IS NOTED TO THE NORTH ACROSS THE
GULF OF MEXICO. IN ADDITION...A COLD FRONT EXTENDS FROM OFFSHORE
OF WESTERN CUBA ACROSS THE YUCATAN CHANNEL TO THE NE TIP OF THE
YUCATAN PENINSULA WITH A PRE-FRONTAL SURFACE TROUGH EXTENDING
FROM 21N83W INTO A 1009 MB LOW NEAR 18N85W TO WESTERN HONDURAS
NEAR 15N87W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE MOSTLY
FOCUSED IN THE VICINITY OF THE SURFACE TROUGH...HOWEVER OVERALL
THE ACTIVITY REMAINS N OF 15N W OF 82W. WHILE THE FRONT WEAKENS
DURING THE NEXT 24 HOURS ACROSS THE NW CARIBBEAN...THE MAIN
MARINE IMPACT IS FRESH TO OCCASIONAL STRONG BREEZE CONDITIONS
GENERALLY E OF 75W DUE TO A STRENGTHENED PRESSURE GRADIENT
ACROSS THE EASTERN CARIBBEAN. THESE CONDITIONS ARE EXPECTED TO
PERSIST THROUGH EARLY SATURDAY.

...HISPANIOLA...
MOSTLY CLEAR SKIES PREVAIL THIS AFTERNOON AND ARE EXPECTED TO
PERSIST DURING THE NEXT FEW DAYS AS DRY UPPER LEVEL ANTICYCLONIC
FLOW ALOFT MAINTAINS STABLE ATMOSPHERIC CONDITIONS ACROSS THE
REGION.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR
IMAGERY OVER THE CAROLINAS THAT SUPPORTS A 1003 MB LOW CENTERED
NEAR 31N77W. THE ASSOCIATED COLD FRONT EXTENDS SW FROM THE LOW
CENTER TO THE SOUTHERN FLORIDA PENINSULA AND LOWER FLORIDA KEYS
TO THE YUCATAN PENINSULA. IN ADDITION...A WARM FRONT EXTENDS
EAST TO 30N70W WHERE THE FRONT BECOMES STATIONARY TO 31N57W.
WEST-SOUTHWESTERLY FLOW ALOFT EXTENDS FROM OVER SOUTHERN MEXICO
AND THE GULF OF MEXICO INTO THE SW NORTH ATLC THAT IS ADVECTING
MOISTURE AND AIDING THE GENERATION OF WIDELY SCATTERED SHOWERS
AND ISOLATED TSTMS ALONG AND IN THE VICINITY OF THE FRONTS N OF
26N BETWEEN 35W-68W...AND N OF 23N W OF 68W. THE AREA OF LOW
PRESSURE IS FORECAST TO DEVELOP FURTHER AS IT MOVES NORTH OF THE
DISCUSSION AREA FRIDAY. THE ASSOCIATED COLD FRONT WILL INTRODUCE
FRESH TO STRONG WEST-NORTHWESTERLY WINDS GENERALLY N OF 28N IN
WAKE OF THE BOUNDARY. OTHERWISE...THE REMAINDER OF THE CENTRAL
AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE
ANCHORED BY A 1025 MB HIGH CENTERED NEAR 35N15W.

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

$$
HUFFMAN



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