000
AXNT20 KNHC 302350
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
805 PM EDT TUE APR 30 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...ITCZ/MONSOON TROUGH... 

THE MONSOON TROUGH EXTENDS FROM THE COAST OF SIERRA LEONE NEAR 
8N13W TO 3N17W. THE ITCZ BEGINS FROM 3N17W AND CONTINUES ALONG 
1N30W EQ40W EQ50W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 
EQ-1N BETWEEN 10W-20W. SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION IS WITHIN 120 NM NORTH OF THE AXIS BETWEEN 25W-37W. 
SIMILAR ACTIVITY IS ALSO FROM 4N-7N BETWEEN 42W-46W. 

...DISCUSSION...

GULF OF MEXICO... 
A LARGE BURST OF SHOWERS/THUNDERSTORMS IS ACROSS THE NORTH 
CENTRAL GULF OF MEXICO. BASED OFF OF LIGHTNING DATA AND RADAR 
IMAGERY...THE HEAVIEST ACTIVITY IS FROM 25N-27N BETWEEN 88W-
93W...AND ALONG A LINE FROM 26N87W TO 31N89W. CLUSTERS OF 
SHOWERS AND THUNDERSTORMS ALSO DOT MUCH OF THE FLORIDA 
PENINSULA. THE ACTIVITY IN THE CENTRAL GULF IS MAINLY CONNECTED 
TO UPPER LEVEL DIFFLUENCE AROUND AN UPPER LEVEL TROUGH MOVING 
ACROSS THE NW GULF WITH AXIS NEAR 94W. A WEAK SURFACE TROUGH IS 
ANALYZED ALONG 28N94W TO 25N93W TO THE WEST OF THE SHOWER 
ACTIVITY...BUT IT IS MAINLY INFLUENCED BY THE UPPER LEVEL 
PATTERN. THE SW GULF REMAINS CLEAR AT THIS TIME AS WELL AS 
PORTIONS OF THE SE GULF. SOUTHEAST SURFACE FLOW OF 10-15 KT 
SPREADS ACROSS THE AREA WITH HIGHER GUSTS IN THE AREAS OF 
SHOWERS/THUNDERSTORMS. MOIST CONDITIONS ARE EXPECTED TO REMAIN 
OVER THE CENTRAL AND EASTERN GULF FOR THE NEXT SEVERAL DAYS AS 
BROAD LOW PRESSURE DEVELOPS IN THE CENTRAL GULF BY THE END OF 
THE WEEK. 
 
CARIBBEAN SEA... 
MOSTLY DRY AIR ALOFT COVERS THE CARIBBEAN IN WESTERLY FLOW. THE 
DRY AIR ALOFT IS HELPING MAINTAIN MOSTLY FAIR CONDITIONS AT THE 
SURFACE. HOWEVER...A FEW AREAS OF ISOLATED SHOWERS/THUNDERSTORMS 
HAVE POPPED UP OVER A FEW OF THE ISLANDS INCLUDING 
CUBA...HISPANIOLA...JAMAICA...AND PUERTO RICO. SCATTERED 
SHOWERS/POSSIBLE THUNDERSTORMS ARE ALSO IN THE VICINITY OF THE 
LESSER ANTILLES FROM 13N-18N EAST OF 64W. THIS ACTIVITY IS TIED 
TO AN AREA OF ENHANCED MOISTURE TO THE EAST OF THE ISLANDS. 
TRADEWIND FLOW OF 15 KT CONTINUES THROUGHOUT THE AREA. LITTLE 
CHANGE IS EXPECTED OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN... 
A SHORTWAVE UPPER TROUGH OFF THE CAROLINAS' COAST IS SUPPORTING 
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THE WEST ATLC 
NORTH OF 26N BETWEEN 72W-78W. AN UPPER LEVEL RIDGE TO THE EAST 
SUPPORTS A WEAK SURFACE RIDGE AROUND A 1022 MB HIGH NEAR 32N70W. 
AN UPPER LEVEL LOW NEAR 35N43W CONTINUES TO SUPPORT AN OCCLUDED 
1004 MB SURFACE LOW NEAR 34N45W. AN ASSOCIATED COLD FRONT 
EXTENDS INTO THE DISCUSSION AREA ALONG 32N42W 27N45W 24N52W. 
SCATTERED SHOWERS EXTEND UP TO 300 NM EAST OF THE AXIS NORTH OF 
27N. BROAD SURFACE RIDGING IS ACROSS THE REMAINDER OF THE EAST 
ATLC SUPPORTED BY AN UPPER LEVEL RIDGE ALONG 30W. 

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

$$ 
WALTON