Tropical Weather Discussion
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000
AXNT20 KNHC 131030
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON APR 13 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 11N16W SW
TO 05N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
04N18W TO 01N26W...ALONG THE EQUATOR TO THE NORTHERN COAST OF
BRAZIL NEAR 02S42W. SCATTERED MODERATE TO STRONG CONVECTION IS
FROM 01N TO 07N BETWEEN 13W AND 26W. SCATTERED MODERATE
CONVECTION IS FROM 05S TO 03N W OF 29W.

...DISCUSSION...

GULF OF MEXICO...

BROAD SURFACE HIGH PRESSURE OVER THE ATLC OCEAN EXTENDS A RIDGE
AXIS SW ACROSS THE FLORIDA PENINSULA AND THE EASTERN GULF...THUS
PROVIDING RETURN WIND FLOW OF 10 TO 15 KT ACROSS THE BASIN.
SOUTHEASTERLY WIND FLOW ACROSS THE BASIN CONTINUES TO ADVECT
ABUNDANT MOISTURE FROM THE CARIBBEAN TO THE NORTHERN
GULF...WHICH ALONG A ZONE OF DIFFLUENT FLOW ALOFT SUPPORT
SCATTERED MODERATE CONVECTION AND TSTMS N OF 28N BETWEEN 85W AND
89W. ON THE NW GULF...HEAVY SHOWERS AND TSTMS ARE N OF 25N W OF
93W ASSOCIATED WITH A SQUALL LINE EXTENDING FROM SE TEXAS NEAR
29N94W TO 25N95W. A 1008 MB LOW OVER CENTRAL MEXICO ALONG
DIFFLUENCE IN THE MIDDLE TO UPPER LEVELS SUPPORT SIMILAR
CONVECTION FROM 22N TO 25N W OF 95W AND SCATTERED SHOWERS S OF
23N W OF 90W. AREAS OF DIFFLUENT FLOW WITHIN AN UPPER RIDGE
MOVING ACROSS THE GULF AND ABUNDANT MOISTURE WILL CONTINUE TO
SUPPORT SHOWERS AND TSTMS ACROSS THE NORTHERN BASIN THROUGH WED
NIGHT. OTHERWISE...SURFACE RIDGING WILL CONTINUE TO BE THE
DOMINANT FEATURE DURING THE NEXT THREE DAYS.

CARIBBEAN SEA...

A BROAD SURFACE RIDGE OVER THE ATLC OCEAN EXTENDS TO THE
NORTHERN AND SE CARIBBEAN WHILE LOW PRESSURE DOMINATES ON THE SW
BASIN BEING ANCHORED BY A 1008 MB LOW OVER NW COLOMBIA. THIS IS
SUPPORTING A TIGHTER PRESSURE GRADIENT OVER THE CENTRAL
BASIN...THUS RESULTING IN TRADES OF 20 TO 25 KT BETWEEN 64W AND
80W...INCREASING TO 30 KT ALONG THE COAST OF COLOMBIA. ELSEWHERE
TRADES OF 15 KT DOMINATE. SSMI TPW IMAGERY CONTINUE TO SHOW
ABUNDANT MOISTURE MOVING ACROSS THE CARIBBEAN SEA...WHICH ALONG
A MIDDLE LEVEL TROUGH OVER THE EASTERN BASIN MAY SUPPORT
ISOLATED SHOWERS OVER THE LESSER ANTILLES...PUERTO RICO AND
HISPANIOLA. SCATTERED MODERATE CONVECTION IS WITHIN 100 NM OF
THE COASTS OF SOUTHERN NICARAGUA...COSTA RICA AND NORTHERN
PANAMA. 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 LEVEL TROUGH EXTENDS FROM THE ATLC SW ACROSS PUERTO
RICO AND HISPANIOLA TO THE CENTRAL CARIBBEAN. PATCHES OF SHALLOW
MOISTURE MOVING WITH THE TRADES ACROSS THE ISLAND ALONG WITH
LIFTING ASSOCIATED WITH THE TROUGH SUPPORT CLOUDINESS WITH
POSSIBLE SCATTERED TO ISOLATED SHOWERS. SIMILAR CONDITIONS ARE
EXPECTED TO PREVAIL THROUGH THIS EVENING. WINDS OVER COASTAL
WATERS ARE OF 20 TO 25 KT.

ATLANTIC OCEAN...

A BROAD UPPER TROUGH OVER THE NW AND CENTRAL ATLC CONTINUE TO
SUPPORT A COLD FRONT ENTERING THE AREA OF DISCUSSION NEAR 30N58W
SW TO 29N65W WHERE IT TRANSITIONS INTO A STATIONARY FRONT ALONG
29N73W TO 30N81W. SCATTERED SHOWERS AND TSTMS ARE ON THE TAIL OF
THE FRONT...ISOLATED SHOWERS ARE N OF THE FRONTAL BOUNDARY. A
BROAD SURFACE RIDGE COVERS THE CENTRAL ATLC ANCHORED BY A 1025
MB HIGH NEAR 29N47W. RECENT SCATTEROMETER DATA SHOW A WEAKNESS
IN THE RIDGE BEING ANALYZED AS A SURFACE TROUGH ALONG 27N58W TO
21N61W AND A SECOND TROUGH FROM 27N66W TO 23N69W WITH NO
CONVECTION. A MIDDLE TO UPPER LEVEL LOW SE OF THE CANARY ISLANDS
CONTINUES TO SUPPORT A COLD FRONT EXTENDING FROM 30N19W SW TO
26N26W TO A WEAK LOW PRESSURE CENTER NEAR 28N35W TO 27N40W WHERE
IT STARTS TO DISSIPATE. NO CONVECTION IS ASSOCIATED WITH THIS
FRONT. THE FRONT OVER THE SW N ATLC IS EXPECTED TO DISSIPATE
TUESDAY AFTERNOON OVER THE CENTRAL BASIN. SURFACE RIDGING WILL
DOMINATE ELSEWHERE DURING THE NEXT TWO DAYS.

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

$$
NR



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