Tropical Weather Discussion
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000
AXNT20 KNHC 181047
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT APR 18 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 07N12W SW
TO 04N17W WHERE THE ITCZ BEGINS AND CONTINUES TO 01S30W TO THE
NORTHERN COAST OF BRAZIL NEAR 01S50W. SCATTERED MODERATE
CONVECTION IS FROM 04S TO 04N BETWEEN 18W AND 34W.

...DISCUSSION...

GULF OF MEXICO...

A 1014 MB LOW PREVAILS OVER SOUTH CAROLINA AND GEORGIA ADJACENT
WATERS FROM WHICH A COLD FRONT EXTENDS SW TO CAPE CANAVERAL
WHERE IT TRANSITIONS TO A STATIONARY FRONT NW TO THE FLORIDA
PANHANDLE...ALONG THE NORTHERN GULF COASTLINE TO A 1008 MB LOW
OVER NE MEXICO. A SURFACE TROUGH IS AHEAD OF THE FRONT ALONG
28N92W SW TO 25N95W. ABUNDANT MOISTURE OVER THE WESTERN AND
NORTHERN GULF EXTENDING INLAND ALONG WITH DIFFLUENT FLOW ALOFT
SUPPORT HEAVY SHOWERS AND TSTMS W OF A LINE FROM 30N87W TO
25N94W. FOG IS ALSO BEING REPORTED OVER THE NW GULF N OF 26N W
OF 90W AND ALSO WITHIN THE VICINITY OF THE FRONT OVER NORTHERN
FLORIDA AND ADJACENT WATERS. MOSTLY SE TO S WIND FLOW OF 15 KT S
OF 25N WHILE LIGHTER VARIABLE WINDS DOMINATE ELSEWHERE. LOW
PRESSURE WILL DOMINATE ACROSS THE GULF TODAY BUT SURFACE RIDGING
REBUILDS SUNDAY MORNING. SHOWERS ACROSS THE NORTHERN GULF WILL
CONTINUE THROUGH SUNDAY.

CARIBBEAN SEA...

A BROAD SURFACE RIDGE OVER THE ATLC OCEAN EXTENDS TO THE
NORTHERN CARIBBEAN WHILE LOWER PRESSURE DOMINATES ELSEWHERE S OF
12N. A SLIGHTLY TIGHTER PRESSURE GRADIENT IS OVER THE CENTRAL
CARIBBEAN ASSOCIATED WITH A 1009 MB LOW OVER N COLOMBIA...THUS
RESULTING IN TRADES OF 20 TO 25 KT S OF 15N BETWEEN 71W AND
78W...BEING THE STRONGEST WINDS ALONG THE COAST OF COLOMBIA.
ELSEWHERE TRADES OF 15 KT DOMINATE. MIDDLE TO UPPER LEVEL
RIDGING IS OVER THE HALF WESTERN BASIN WHILE A TROUGH COVERS THE
REMAINDER BASIN. DEEP LAYER MOISTURE OVER THE SE CARIBBEAN ALONG
WITH A DIFFLUENT ENVIRONMENT SUPPORT SCATTERED SHOWERS OVER THE
WINDWARD ISLANDS AND ADJACENT WATERS. SSMI TPW IMAGERY SHOW
PATCHES OF SHALLOW MOISTURE MOVING ACROSS THE NW AND NE
BASIN...THUS SUPPORTING CLOUDINESS AND POSSIBLE SCATTERED TO
ISOLATED SHOWERS OVER THE VIRGIN ISLANDS...PUERTO RICO...WESTERN
HISPANIOLA...JAMAICA AND THE WINDWARD PASSAGE. ISOLATED SHOWERS
ARE ON PANAMA AND COSTA RICA COASTAL WATERS. FAIR WEATHER IS
ELSEWHERE BEING SUPPORTED BY DRY AIR SUBSIDENCE FROM ALOFT. NOT
SIGNIFICANT CHANGES ARE EXPECTED DURING THE NEXT TWO DAYS.

...HISPANIOLA...

A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM THE SW N ATLC S
ACROSS THE ISLAND TO NORTHERN VENEZUELA. SHALLOW MOISTURE ALONG
WITH LIFTING PROVIDED BY THE UPPER TROUGH SUPPORT CLOUDINESS
WITH POSSIBLE SCATTERED TO ISOLATED SHOWERS...MAINLY FOCUSED
OVER HAITI AND THE WINDWARD PASSAGE. SHOWERS ARE EXPECTED TO
CONTINUE THROUGH SATURDAY MORNING WHEN A DRY AIRMASS ENTERS THE
ISLAND PROVIDING FAIR WEATHER CONDITIONS THROUGH SUNDAY EVENING.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL TROUGH OVER THE NORTH-CENTRAL ATLC
CONTINUE TO SUPPORT A SURFACE LOW PRESSURE SYSTEM FROM WHICH A
COLD FRONT EXTENDS SW ENTERING THE AREA OF DISCUSSION FROM
30N32W SW TO 25N47W WHERE IT TRANSITIONS TO A STATIONARY FRONT
ALONG 27N55W. FROM THAT POINT A WARM FRONT EXTENDS NW TO 28N60W
TO 30N66W. ISOLATED SHOWERS ARE WITHIN 50 NM EITHER SIDE OF THE
FRONTAL BOUNDARY. A 1014 MB LOW OVER GEORGIA ADJACENT WATERS
EXTENDS A COLD FRONT SW TO CAPE CANAVERAL ENHANCING SCATTERED
SHOWERS AND TSTMS MAINLY AHEAD OF THE FRONT N OF 26N W OF 72W.
SURFACE RIDGING AND FAIR WEATHER DOMINATES ELSEWHERE.

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

$$
NR



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