000
AXNT20 KNHC 301834
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON MAR 30 2009

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1645 UTC.

...ITCZ...
FROM 05N09W TO 00N30W TO 01S37W TO COAST OF BRAZIL AT 01S46W.  
NUMEROUS MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM OF 
AXIS E OF 17W THEN SCATTERED MODERATE FROM 17W-26W.  ISOLATED 
MODERATE WITHIN 90 NM OF AXIS W OF 40W. 

...DISCUSSION...
UPPER LEVELS...
FLOW ALOFT BECOMING QUASI-ZONAL AS LONGWAVE TROUGH SUPPORTING 
SURFACE COLD FRONT OVER SW N ATLC WEAKENS AND SHIFTS NE.  WEAK 
UPSTREAM RIDGE CREST FLATTENS UNDER INFLUENCE OF NEW CYCLONIC 
VORTEX ACROSS CENTRAL PLAINS.  EXCEPT THE MOISTURE ASSOCIATED 
WITH COLD FRONT ALONG SW N ATLC...REMAINDER OF FORECAST AREA 
REMAINS UNDER MODERATE TO STRONG SUBSIDING AIR MASS WHICH
INHIBITS CLOUD DEVELOPMENT.  LARGE AMPLITUDE LONG WAVE UPPER 
LEVEL TROUGH ACROSS CENTRAL ATLC FROM 31N35W TO 17N52W TO 13N61W 
SUPPORTS ILL DEFINED STATIONARY FRONT FROM 31N31W TO 19N42W.
RIDGE OVER AFRICAN CONTINENT BRINGS ONLY SIGNIFICANT AMOUNT OF 
TROPICAL MOISTURE INTO E ATLC MAINLY S OF 15N W OF 40W.  
    
ELSEWHERE AT THE SURFACE...
GULF OF MEXICO...
HIGH PRESSURE RIDGE COVER EASTERN HALF OF GULF WITH LOW LEVEL 
STRATIFIED CLOUDS OF LITTLE OR NO VERTICAL DEVELOPMENT.  
MOISTURE FROM TAIL END OF STATIONARY FRONT OVER STRAITS OF 
FLORIDA PROMPTING BROKEN TO OVERCAST LOW LEVEL CLOUDS WITH 
ISOLATED SHOWERS S OF 27N E OF 87W.  REMAINDER GULF CARRIES 
MOSTLY SCATTERED LOW CLOUDS AND BRIEF ISOLATED ALONG COASTAL 
SECTIONS.  ANOTHER COLD FRONT FORECAST TO APPROACH BASIN BY TUE.
     
CARIBBEAN SEA...
VERY WEAK ANTICYCLONIC FLOW COVERS ENTIRE AREA WITH DRY AIR MASS 
DUE TO MODERATE TO STRONG SUBSIDENCE.  ONLY MOISTURE MOVING N 
FROM OVER SOUTH AMERICA CONTINENT IS IMMEDIATELY DRIED OVER THE 
CARIBBEAN BASIN ALLOWING ONLY ISOLATED SHOWERS OF SHORT 
DURATION.  EVEN MOISTURE FROM STATIONARY FRONT FROM WESTERN TIP 
OF CUBA TO BELIZE QUICKLY DISAPPEAR WHEN MIXED WITH CARIBBEAN 
SUBSIDING AIR MASS. 

ATLANTIC OCEAN...
STATIONARY FRONT FROM 31N31W TO 19N42W PROMPTING SCATTERED DEEP 
CONVECTION MOSTLY N OF 28N FROM 26W-32W.  MOISTURE INCOMING OVER 
CANARY ISLANDS ADVECTED BY RIDGE OVER AFRICAN CONTINENT 
PROMPTING SCATTERED SHOWERS.  HIGH PRESSURE RIDGE AXIS FROM 
31N20W TO 16N29W.

$$
WALLY BARNES