000
AXNT20 KNHC 281708
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI APR 28 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 
SECTIONS OF SOUTH AMERICA...AND THE 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 
1715 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N1W 3N20W 1N40W 1N50W. SCATTERED 
MODERATE AND ISOLATED STRONG CONVECTION IS NOTED WITHIN 240 NM N 
OF THE AXIS E OF 22W. SCATTERED MODERATE CONVECTION IS NOTED 
FROM 9N TO 7S BETWEEN 25W AND 50W.

...DISCUSSION...
GULF OF MEXICO...
AN UPPER ANTICYCLONE IS CENTERED NEAR VARACRUZ MEXICO NEAR 
17N95W. A RIDGE EXTENDS N ACROSS THE GULF OF MEXICO INTO THE  
ALONG 30N95W CONTINUING E INTO THE CENTRAL UNITED STATES. THE 
UPPER FLOWS DIVES SE ACROSS ALABAMA INTO THE WESTERN ATLANTIC 
NEAR 25N78W WHERE THE UPPER FLOW THEN TURNS CYCLONIC INTO A 
SHORTWAVE TROUGH.  MOISTURE STREAMING NE FROM ITCZ CONVECTION 
OVER THE E PACIFIC BETWEEN 115W AND 129W...STREAMS ACROSS 
NORTHERN MEXICO ALONG WESTERN EDGE OF THE RIDGE...ROUGHLY WITHIN 
200 NM EITHER SIDE OF LINE 24N106W 27N101W 32N96W. AT THE 
SURFACE...THE COLD FRONT CONTINUES TO PUSH IT WAY THROUGH THE 
FLORIDA STRAITS BECOMING ILL DEFINED AS IT PUSHES ITS WAY INTO 
CUBA...AXIS EXTENDS FROM 23N87W EAST OVER THE CENTRAL BAHAMAS 
INTO THE WESTERN ATLANTIC. DRY UPPER AIR IS INDICATED OVER THE 
EASTERN GULF E OF 85W SUPPRESSING CONVECTION. 

CARIBBEAN SEA...
ALOFT...A UPPER LEVEL SHORTWAVE TROUGH EXTEND ACROSS THE NW 
PORTIONS OF THE CARIBBEAN SEA ENTERS THE AREA ALONG 20N75W TO 
15N78W....THIS TROUGH IS BRINING DRY AIR ALOFT TO THE WEST 
INDIES. ELSEWHERE...OVER THE SOUTHEASTERN CARIBBEAN BROAD 
ANTICYCLONIC FLOW DOMINATES THE AREA...STREAMING MOISTURE INTO 
THE AREA S OF 16N... AT THE LOWER LEVEL MOISTURE FROM CONVECTION 
S OF 12N BETWEEN 68W AND 81W SPREADS NE IN THE ANTICYCLONIC FLOW 
ACROSS THE CENTRAL AND EASTERN CARIBBEAN SEA. OTHERWISE ISOLATED 
TRADE WIND CUMULUS IS MOVING W THROUGH THE WATERS S OF 20N. 

ATLANTIC OCEAN...
THE WESTERN SW N ATLC CONTINUES TO BE DOMINATED BY A SHORTWAVE 
TROUGH WITH ITS MEAN AXIS LYING N TO S ALONG 73W. DIFFLUENCE E 
OF THE TROUGH ASSOCIATED WITH A SURFACE COLD FRONT CONTINUES TO 
ENHANCING CONVECTION AHEAD.  THE FRONT CURRENTLY EXTENDS FROM A 
1008 MB LOW NEAR 32N72W TO 22N87W. THE CONVECTION WELL OUT IN 
FRONT AND IS CONCENTRATED WITHIN 60 NM EITHER SIDE OF LINE  FROM 
30N67W 27N70W.  IMMEDIATELY E...A SHORTWAVE RIDGE EXTENDS N FROM 
NEAR 19N61W  ALONG 26N57W 32N56W...THEN CONTINUES NE TO WELL N 
OF THE AREA EFFECTIVELY SEPARATING THE TROUGH ALONG THE E COAST 
OF CONUS FROM A LONGWAVE TROUGH THAT DOMINATES THE CENTRAL N 
ATLC. AT THE SURFACE...1030 MB HIGH LOCATED NEAR 39N41W WITH 
RIDGE EXTENDING SW TO NEAR 25N64W CONTINUES TO DOMINATE.
THE EXTREME E ATLC...AN UPPER ANTICYCLONE IS ESTIMATED NEAR 8N7E 
AND RIDGES W ALONG 7N47W. 

$$
JP/LL