000
AXNT20 KNHC 112342
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
805 PM EDT MON APR 11 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION OF 
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE 
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE 
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND 
RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2330 UTC.

...THE ITCZ...

ITCZ AXIS IS ANALYZED S OF THE EASTERN IVORY COAST NEAR 2N7W... 
CONTINUING WSW ALONG 1N20W 2S30W 1S40W INT0 BRAZIL NEAR 1S47W. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 3S-5N 
BETWEEN 10W-30W SCATTERED MODERATE CONVECTION IS WITHIN 150 NM 
ON EITHER SIDE OF THE AXIS W OF 30W. 

...DISCUSSION...

THE GULF OF MEXICO...
A DEEP LAYER TROUGH MOVES ACROSS THE CENTRAL CONUS. THIS FEATURE 
SUPPORTS A COLD FRONT MOVING THROUGH THE FAR WEST GULF ANALYZED 
FROM WESTERN LOUISIANA TO TAMPICO MEXICO ALONG 30N92W 26N96W 
21N97W. THIS FRONTAL BOUNDARY CAN BE TRACKED BY A THIN CLOUD 
LINE ON SATELLITE VISIBLE THAT IS NOT PRODUCING ANY CONVECTION 
AT ALL. MARINE OBS ACROSS THE BASIN INDICATE 10-20 KT RETURN 
FLOW AHEAD OF THE FRONT...WHILE 10-15 KT NW FLOW BEHIND THE 
FRONT. ASIDE THE FRONTAL BOUNDARY...FAIR WEATHER CONDITIONS ARE 
NOTED ACROSS THE GULF. SHORT RANGE COMPUTER MODELS SUGGEST THIS 
FRONT WILL CONTINUE TO MOVE EASTWARD WITH LIMITED CONVECTION 
OVER THE NEXT 24 HOURS.

THE CARIBBEAN SEA...
WATER VAPOR IMAGERY SHOWS VERY DRY AIR AND STRONG SUBSIDENCE 
ALOFT ACROSS THE CENTRAL AND WESTERN CARIBBEAN THIS AFTERNOON. 
THIS IS KEEPING WEATHER CONDITIONS FAIR OVER THE A GREAT PORTION 
OF THE DISCUSSION AREA W OF 70W. HOWEVER...A SURFACE TROUGH IS 
MOVING ACROSS THE FAR E CARIBBEAN...ANALYZED FROM 17N64W TO 
10N66W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ASSOCIATED 
TO THIS SYSTEM ARE E OF A LINE FROM 18N64W TO 11N71W.AN UPPER 
LEVEL LOW SITTING OVER HISPANIOLA AND A BROAD ANTI-CYCLONIC 
CIRCULATION CENTERED OVER THE FAR WEST TROPICAL ATLC IS FURTHER 
ENHANCING THE CONVECTION IN THIS REGION BY PROVIDING A SWLY DEEP 
LAYER MOISTURE FLOW NOTED ON WATER VAPOR AND TOTAL PRECIPITABLE 
WATER IMAGERY. WEATHER CONDITIONS IN THIS REGION WILL REMAIN 
CONSTANT OVER THE NEXT 24 TO 48 HOURS. 

THE ATLANTIC OCEAN...
A DEEP LAYERED TROUGH/OCCLUDED LOW MOVE ACROSS THE N CENTRAL 
ATLC SUPPORTING A COLD FRONT THAT ENTERS THE AREA FROM 32N44W TO 
29N50W TO 28N57W...DISSIPATING FROM THIS POINT TO 21N70W. A 
SURFACE TROUGH THEN CONTINUES PARALLEL TO THE BAHAMAS TO NEAR 
30N77W. SCATTERED WEAK CONVECTION IS WITHIN 80 NM ON EITHER SIDE 
OF THE COLD FRONT E OF 52W. NO CONVECTION IS OBSERVED IN THE 
VICINITY OF THE COLD FRONT W OF 52W. OTHER THAN A WIND SHIFT 
FROM NE TO SW ALONG THE SURFACE TROUGH...NO CONVECTION IS 
OBSERVED ALONG THE TROUGH. S OF THIS FRONTAL SYSTEM...A NEARLY 
STATIONARY WEAK 1016 MB LOW IS NEAR 22N61W WITH A SURFACE TROUGH 
EXTENDING FROM 25N58W TO THE LOW CENTER TO 20N62W. THE 
CONVECTION ASSOCIATED WITH THIS SYSTEM IS WEAK AND DISPLACED 
FROM 21N-25N BETWEEN 56W-62W. THIS SYSTEM WILL CONTINUE TO 
WEAKEN OVER THE NEXT 12-18 HOURS. THE REMAINDER OF THE ATLC E OF 
45W IS UNDER SURFACE RIDGING AXIS FROM THE NE ATLC TO 20N50W.

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

$$

GARCIA