000
AXNT20 KNHC 141751
TWDAT 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL 
205 PM EDT SUN APR 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 
1715 UTC.

...ITCZ/MONSOON TROUGH... 

THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST OF SIERRA 
LEONE NEAR 08N12W. THE INTERTROPICAL CONVERGENCE ZONE AXIS 
EXTENDS FROM 08N12W TO 01N18W 01S25W EQ43W. WIDELY SCATTERED 
MODERATE CONVECTION IS N OF 02S E OF 12W...FROM 07S TO 03S 
BETWEEN 15W AND 26W AS WELL AS FROM 02S TO 03N BETWEEN 22W AND 
49W. 
 
...DISCUSSION...

GULF OF MEXICO...                                               
AS OF 1500 UTC...A WARM FRONT EXTENDS FROM A 1008 MB LOW OVER SE 
LOUISIANA TO 29N89W 29N87W 29N85W 29N82W AND ACROSS N FLORIDA. A 
SURFACE TROUGH ALSO EXTENDING FROM THE LOW IS ALONG 29N90W 
25N91W 22N92W. THIS FRONTAL SYSTEM IS BEING SUPPORTED BY A 
MIDDLE-UPPER LEVEL SHORTWAVE TROUGH WITH AXIS CROSSING TO THE 
LOWER MISSISSIPPI VALLEY. RADAR IMAGERY AND LIGHTNING DATA 
INDICATE NUMEROUS RAINSHOWERS AND THUNDERSTORMS ARE OCCURRING N 
OF 28N BETWEEN 85W AND 90W. SCATTERED SHOWERS ARE N OF 28N E OF 
85W. THIS CONVECTION IS LARGELY DUE TO LOW-LEVEL MOISTURE 
CONVERGENCE IN THE VICINITY OF THE FRONTAL BOUNDARY. SCATTERED 
SHOWERS ARE AHEAD OF THE SURFACE TROUGH FROM 25N TO 28N EAST OF 
91W. FOG AND HAZE HAVE BEEN REPORTED OVER THE NE GULF N OF 25N  
AS WELL AS WITHIN 35 NM W OF THE SURFACE TROUGH N OF 27N. MOSTLY 
SE-S FLOW IN THE RANGE OF 5 TO 10 KT SPREAD OVER THE WESTERN 
GULF W OF 93W. STRONGER SE-S FLOW UP TO 25 KT COVERS THE 
REMAINDER OF THE BASIN S OF THE WARM FRONT. OVER THE COURSE OF 
24 HOURS...THE WARM FRONT IS EXPECTED TO DRIFT NORTHEASTWARD  
ACROSS NORTHERN FLORIDA LATER TODAY AND THEN MERGES WITH A 
FORMING LOW OFF THE CAROLINAS COASTS. SOUTHEASTERLY FLOW WILL 
BUILD OVER THE BASIN BY THEN.
 
CARIBBEAN SEA...                                        
A RELATIVELY TIGHT PRESSURE GRADIENT DUE TO A BROAD HIGH 
PRESSURE OVER THE ATLC AND A LOW OVER COLOMBIA IS PROVIDING 
EASTERLY TRADEWINDS UP TO 25 KT OVER THE EASTERN...CENTRAL AND 
SOUTHERN CARIBBEAN. SE FLOW OF THE SAME MAGNITUDE SPREAD OVER 
THE W CARIBBEAN W OF 80W. IN THE MIDDLE-UPPER LEVELS SW-W FLOW 
IS ACROSS THE BASIN ASSOCIATED TO A RIDGE ANCHORED OVER PANAMA. 
WATER VAPOR IMAGERY SHOW DRY AIR ALOFT ACROSS MOST OF THE BASIN 
WHICH IS SUPPRESSING CONVECTIVE ACTIVITY. SCATTERED SHOWERS ARE 
POSSIBLE S OF 15N IN THE SOUTHERN CARIBBEAN IN ASSOCIATION WITH 
A 1008 MB LOW IN NORTHERN COLOMBIA AND THE MONSOON TROUGH. THIS 
OVERALL SYNOPTIC PATTERN IS EXPECTED TO PERSIST THROUGH THE NEXT 
24 HOURS. 

ATLANTIC OCEAN...                                               
AS OF 1500 UTC...THE PORTION OF THE GULF WARM FRONT THAT EXTENDS 
TO THE W ATLC HAS WEAKENED AND TRANSITIONED TO A DYING WARM 
FRONT ALONG 30N74W 29N80W. SCATTERED SHOWERS AND ISOLATED 
THUNDERSTORMS ASSOCIATED TO THIS FRONT ARE WITHIN 100 NM S OF 
THE BOUNDARY WEST OF 78W. BROAD SURFACE RIDGING IS ACROSS THE 
EASTERN...CENTRAL AND W ATLC E OF 70W ANCHORED BY A 1024 MB HIGH 
LOCATED NEAR 28N50W. THE TAIL OF A DISSIPATING COLD FRONT 
EXTENDS FROM 30N31W TO 29N38W BEING SUPPORTED BY A MIDDLE-UPPER 
LEVEL TROUGH THAT EXTENDS SOUTHWESTWARD ACROSS THE CENTRAL ATLC 
FROM 31N31W TO 11N53W. NO CONVECTIVE PRECIPITATION IS ASSOCIATED 
TO THIS FRONT. OVER THE COURSE OF 24 HOURS...RAINSHOWERS AND 
POSSIBLE THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER THE W ATLC 
W OF 73W N OF 27N AS THE WARM FRONT OVER THE NE GULF CONTINUES A 
NORTHEASTWARD TRACK TOWARDS THE COASTAL WATERS OF THE CAROLINAS. 

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

$$
NR