000
AXNT20 KNHC 130003
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
805 PM EDT TUE APR 12 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 2345 UTC.

...THE ITCZ...

ITCZ AXIS IS ANALYZED FROM THE EASTERN IVORY COAST NEAR 5N4W... 
CONTINUING WSW ALONG 2N10W...CROSSING THE EQUATOR AT 20W...3S30W 
THEN INT0 NE BRAZILIAN COAST NEAR 5S37W. SCATTERED TO ISOLATED 
MODERATE CONVECTION IS OBSERVED FROM 3S-3N BETWEEN 17W-24W.  
SCATTERED TO ISOLATED MODERATE CONVECTION IS WITHIN 140 NM S OF 
THE AXIS W OF 28W. 

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 21 UTC A DEEP LAYER TROUGH WITH AXIS NEAR 80W IS SUPPORTING A 
COLD FRONT THAT EXTENDS WESTWARD IN THE GULF AND THEN CROSS THE 
BAY OF CAMPECHE INTO MEXICO. THIS COLD FRONT IS ANALYZED FROM 
30N79W...CROSSING THE EASTERN COAST OF FLORIDA NEAR 29N81W THEN 
IN THE GULF ALONG 28N83W 25N90W 18N94W. SATELLITE VISIBLE SHOWS 
A THIN FRONTAL BOUNDARY WITH NO CONVECTION ASSOCIATED TO IT. A 
PREFRONTAL TROUGH THAT EXTENDS TO THE W COAST OF CENTRAL FLORIDA 
IS ANALYZED ALONG 30N78W 28N81. RADAR IMAGERY SHOWS THUNDERSTORMS 
WITHIN 30 NM OF THIS TROUGH. ELSEWHERE IN THE GULF...FAIR 
WEATHER CONDITIONS ARE NOTED DUE TO STRONG DRY AIR SUBSIDENCE 
FROM THE UPPER LEVEL. EXPECT IN 24 HOURS FOR THE FRONT TO 
CONTINUE ITS EASTWARD MOVEMENT WITH LIMITED CONVECTION. 

THE CARIBBEAN SEA...
WATER VAPOR IMAGERY SHOWS VERY DRY AIR AND STRONG SUBSIDENCE 
ALOFT ACROSS THE CENTRAL AND WESTERN CARIBBEAN. THIS IS KEEPING 
WEATHER CONDITIONS FAIR OVER GREAT PORTION OF THE DISCUSSION 
AREA W OF 68W. EAST OF 68W...A SURFACE TROUGH IS ANALYZED FROM 
10N68W TO 19N68W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS 
ASSOCIATED TO THIS SYSTEM ARE FROM 12N-18N BETWEEN 60W-68W. AN 
UPPER LEVEL TROUGH WITH AXIS NEAR 75W CLOSE TO 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 FAIRLY CONSTANT OVER THE NEXT 24 TO 
48 HOURS. 

THE ATLANTIC OCEAN...
IN THE W ATLANTIC A COLD FRONT BEING SUPPORTED BY AN UPPER LEVEL 
DEEP LAYERED TROUGH ENTERS THE AREA FROM 30N79W TO THE EASTERN 
FLORIDA COAST NEAR 29N80W. A PREFRONTAL TROUGH WITH SHOWERS AND 
THUNDERSTORMS ASSOCIATED TO IT IS ALONG 30N78W 28N80W. IN THE 
CENTRAL N ATLANTIC A COLD FRONT FOLLOWED BY A SHEAR LINE 
CONTINUE TO WEAKEN. THE DISSIPATING COLD FRONT IS ANALYZED FROM 
30N46W TO 26N53W WHERE A SHEAR LINE STARTS AND CONTINUES 
WESTWARD TO 25N68W. LIMITED SHOWERS TO THE E SIDE OF THE 
BOUNDARY MIGHT BE ASSOCIATED TO THIS SYSTEM. THIS SYSTEM WILL 
CONTINUE TO WEAKEN OVER THE NEXT 12-18 HOURS. THE REMAINDER OF 
THE ATLC E OF 38W IS UNDER SURFACE AND UPPER LEVEL RIDGING 
BRINGING FAIR WEATHER CONDITIONS.

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

$$

RAMOS