000
AXNT20 KNHC 291745
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
205 PM EDT TUE MAR 29 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1715 UTC.

...ITCZ...

ITCZ AXIS IS ANALYZED ALONG 07N13W 06N15W 03N18W CROSSING THE 
EQUATOR NEAR 32W THEN INTO NE BRAZIL NEAR 02S43W. SCATTERED 
MODERATE CONVECTION IS FROM THE EQUATOR TO 03N BETWEEN 13W-19W. 
ISOLATED MODERATE CONVECTION IS WITHIN 150 NM N OF THE AXIS 
BETWEEN 22W-32W AND FROM THE EQUATOR TO 02N BETWEEN 32W-45W.

...DISCUSSION...

GULF OF MEXICO...
A WEAK UPPER LEVEL SHORTWAVE TROUGH IS POSITIONED ALOFT OVER THE 
SW NORTH ATLC WATERS WITH CONTINUES TO SUPPORT A VERY WEAK 
STATIONARY FRONTAL BOUNDARY THAT EXTENDS ALONG 29N FROM DAYTONA 
BEACH FLORIDA WESTWARD INTO THE NE GULF WATERS NEAR 29N87W. 
LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE FRONT IS 
GENERATING POSSIBLE ISOLATED SHOWERS N OF 27N E OF 88W. ALSO... 
LIGHTNING DATA IS DETECTING A SMALL AREA OF SCATTERED SHOWERS 
AND ISOLATED TSTMS FROM 26N-28N BETWEEN 86W-89W. THE REMAINDER 
OF THE GULF IS CONTINUING TO SEE SOUTHERLY FLOW IN THE RANGE OF 
10-15 KT THIS AFTERNOON UNDER BROAD UPPER LEVEL RIDGING ALOFT. 
THE RIDGE IS PRODUCING MOIST SOUTHWESTERLY FLOW OVER MOST OF THE 
WESTERN GULF WITH INCREASED CLOUDINESS AND WARM AIR ADVECTION 
AHEAD OF THE NEXT COLD FRONT FORECAST TO ENTER THE NW GULF 
WATERS EARLY WEDNESDAY.  

CARIBBEAN SEA...
THE MAIN FEATURE IN THE CARIBBEAN SEA THIS AFTERNOON IS THE W-NW 
MOVEMENT OF A SURFACE TROUGH ANALYZED FROM 11N62W TO 19N62W 
ACROSS THE LESSER ANTILLES. THIS WEAKNESS IS LOCATED ON THE 
SOUTHWESTERN PERIPHERY OF A CENTRAL ATLC RIDGE AND IS FORECAST 
TO MOVE INTO THE VICINITY OF THE US/UK VIRGIN ISLANDS AND PUERTO 
RICO OVER THE NEXT 24 TO 36 HOURS. ISOLATED TO WIDELY SCATTERED 
SHOWERS ARE OCCURRING FROM 12N-19N BETWEEN 60W-64W...WITH THIS 
AREA OF GRADUALLY TRANSLATE WEST-NORTHWESTWARD THROUGH LATE 
TUESDAY. THIS SHOWER ACTIVITY WILL BE FAIRLY LIMITED IN VERTICAL 
EXTENT DUE TO VERY DRY AIR AND SUBSIDENCE ALOFT. THE UPPER AIR 
SOUNDING AT 29/1200 UTC FROM SAN JUAN PUERTO RICO INDICATED THIS 
DRY AIR ABOVE APPROXIMATELY 700 MB. ELSEWHERE...THE REMAINDER OF 
THE CARIBBEAN IS EXPERIENCING MOSTLY FAIR WEATHER CONDITIONS DUE 
TO SUCH DRY AIR ALOFT. WATER VAPOR IMAGERY INDICATES THE DRY AIR 
EXTENDS WESTWARD TO 90W OVER PORTIONS OF CENTRAL AMERICA. 
OTHERWISE...FRESH TO STRONG TRADES CONTINUE AND ARE EXPECTED TO 
PERSIST THROUGH THE WEEKEND.

ATLANTIC OCEAN...
A WESTERN NORTH ATLC DEEP LAYER TROUGH IS LOCATED MOSTLY NORTH 
OF THE DISCUSSION AREA...HOWEVER...THE ASSOCIATED COLD FRONT 
EXTENDS INTO THE AREA NEAR 32N63W SW TO 31N67W THEN BECOMES 
STATIONARY TO THE FLORIDA COAST NEAR DAYTONA BEACH. ISOLATED 
SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE FRONT. A 
PRE-FRONTAL SURFACE TROUGH IS ANALYZED FROM 30N68W TO GRAND 
BAHAMA ISLAND NEAR 27N78W THEN INLAND TO LAKE OKEECHOBEE. 
LOW-LEVEL CONVERGENCE IN THE VICINITY OF THE SURFACE TROUGH IS 
GENERATING WIDELY SCATTERED SHOWERS WITHIN 120 NM EITHER SIDE OF 
THE SURFACE TROUGH AXIS. THIS ACTIVITY CONTINUES TO BE ENHANCED 
BY A WEAK UPPER LEVEL SHORTWAVE TROUGH WITH AXIS ALONG 79W. THE 
REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE 
OF A SURFACE RIDGE ANCHORED BY A 1029 MB HIGH CENTERED NEAR 
33N28W. THE SURFACE RIDGE AXIS EXTENDS SW FROM THE HIGH CENTER 
THROUGH 30N35W TO 25N65W.

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

$$
HUFFMAN