000
AXNT20 KNHC 281702
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
205 PM EDT SUN APR 28 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 
1645 UTC.

...ITCZ/MONSOON TROUGH... 

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL 
ATLC NEAR 7N12W TO 4N19W WHERE THE ITCZ BEGINS AND CONTINUES 
ALONG 3N27W 1N33W 1N46W THEN INTO SOUTH AMERICA NEAR EQUATOR AND 
51W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 
NM EITHER SIDE OF THE ITCZ BETWEEN 20W-25W. CLUSTERS OF SIMILAR 
CONVECTION ARE FROM 1N TO S OF THE EQUATOR BETWEEN 4W-13W. 
SCATTERED MODERATE CONVECTION IS FROM 2N-5N BETWEEN 38W-42W.  

...DISCUSSION...

GULF OF MEXICO...                                               
A BROAD UPPER RIDGE COVERS THE GULF EXTENDING FROM THE E PACIFIC 
REGION ACROSS MEXICO INTO THE GULF NEAR VERACRUZ TO OVER THE N 
GULF COAST NEAR APALACHICOLA BAY FLORIDA. AN UPPER TROUGH IS 
MOVING TOWARD THE GULF EXTENDING FROM THE GREAT LAKES SW TO THE 
SOUTHERN PLAIN STATES SUPPORTING A FRONTAL BOUNDARY THAT REMAINS 
INLAND AT THIS TIME. A WEAK SURFACE TROUGH EXTENDS AT 28/1500 
UTC FROM SE LOUISIANA N OF NEW ORLEANS INTO THE GULF ON THE E 
SIDE OF ATCHAFALAYA BAY TO 28N93W. SCATTERED SHOWERS/ 
THUNDERSTORMS ARE WITHIN 45 NM E OF THE TROUGH. ISOLATED SHOWERS 
ARE OVER THE NW CARIBBEAN N OF 25N W OF 90W. A SECOND WEAK 
SURFACE TROUGH IS FROM 28N97W TO INLAND OVER TEXAS S OF CORPUS 
CHRISTI WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 45 
NM S OF THE TROUGH. THE W ATLC SURFACE RIDGE REMAINS OVER THE E 
GULF TO NEAR 90W. A THIRD SURFACE TROUGH IS IN THE BAY OF 
CAMPECHE EXTENDING FROM 23N95W TO MEXICO NEAR 18N93W. 
INFORMATION FROM NESDIS INDICATES THE W GULF IS DOMINATED BY 
SMOKE FROM FIRES OVER S MEXICO WITH VISIBLE SATELLITE IMAGERY 
CONFIRMING THE AREA S OF 25N W OF 92W. ISOLATED SHOWERS ARE IN 
THE SE GULF FROM 24N-26N BETWEEN 81W-85W LEAVING THE REMAINDER 
OF THE GULF WITH MOSTLY CLEAR SKIES THIS AFTERNOON. W ATLC RIDGE 
WILL REMAIN THROUGH MID WED AS A WEAK TROUGH REMAINS ANCHORED 
OVER S GULF OF MEXICO. COLD FRONT WILL MOVE OFF TEXAS COAST THU 
AND REACH FROM S CENTRAL LOUISIANA TO TAMPICO MEXICO LATE THU. 
 
CARIBBEAN SEA...                                              
THE BROAD UPPER RIDGE OVER THE GULF OF MEXICO EXTENDS OVER THE W 
CARIBBEAN W OF 80W. THE BROAD UPPER TROUGH OVER THE W/CENTRAL 
ATLC EXTENDS OVER THE CARIBBEAN E OF 80W ACROSS THE LESSER 
ANTILLES. WATER VAPOR SATELLITE IMAGERY SHOWS DRY STABLE AIR 
OVER THE CARIBBEAN W OF 67W. TRADE WINDS ACROSS THE BASIN ARE 
GENERATING ISOLATED SHOWERS WITHIN 60 NM OF LINE FROM 16N64W AND 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM OF LINE 
FROM 19N79W TO 22N83W INCLUDING THE CAYMAN ISLANDS AND THE ISLE 
OF YOUTH. AN UPPER RIDGE OVER THE TROPICS IS DRAWING MOISTURE 
ALOFT ACROSS THE FAR E CARIBBEAN GENERATING SCATTERED SHOWERS S 
OF 16N BETWEEN 59W-63W INCLUDING THE LESSER ANTILLES. THIS IS 
LEAVING THE REMAINDER OF THE CARIBBEAN UNDER MOSTLY CLEAR SKIES 
THIS AFTERNOON. MODERATE TO FRESH TRADE WINDS WILL PERSIST 
ACROSS BASIN THROUGH THU.  

ATLANTIC OCEAN...                                               
A BROAD UPPER TROUGH COVERS THE W ATLC SUPPORTING A COLD FRONT N 
OF THE DISCUSSION AREA AND A SURFACE TROUGH THAT EXTENDS INTO  
THE W ATLC THROUGH 32N61W TO 26N65W. SCATTERED SHOWERS ARE 
WITHIN 60 NM E OF THE TROUGH. A SECOND WEAKER SURFACE TROUGH IS 
TO THE E FROM 31N58W TO 28N57W. A THIRD SURFACE IS TO THE S 
EXTENDING FROM 23N65W TO 20N65W. A BROAD E/W UPPER RIDGE EXTENDS 
FROM AFRICA TO SOUTH AMERICA ANCHORED NEAR 8N36W. THIS UPPER 
FLOW IS DRAWING TROPICAL MOISTURE OVER THE TROPICAL ATLC AND THE 
SE CARIBBEAN GENERATING SCATTERED SHOWERS WITHIN 150/175 NM OF A 
LINE FROM OVER SOUTH AMERICA NEAR 10N61W ALONG 20N39W TO AFRICA 
NEAR 23N16W. THE REMAINDER OF THE ATLC IS UNDER NEAR ZONAL 
WESTERLY FLOW ALOFT AND WITH FAIR WEATHER THIS AFTERNOON. GENTLE 
TO MODERATE EASTERLY BREEZE THROUGH THU. 

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

$$ 
PAW