000
AXNT20 KNHC 041803
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN MAR 04 2012

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1700 UTC.

...ITCZ/MONSOON TROUGH...

MONSOON TROUGH EXTENDS FROM INLAND ACROSS TROPICAL REGION OF 
AFRICAN CONTINENT AND EXITS WEST COAST THROUGH LIBERIA AT 5N10W 
CONTINUING SW TO 1N18W WHERE IT TRANSITIONS TO ITCZ CONTINUING 
TO EQ24W TO NE COAST OF BRAZIL AT 3S42W.  SCATTERED MODERATE 
CONVECTION WITHIN 120 NM OF 3N18W.  ISOLATED MODERATE CONVECTION 
WITHIN 150 NM N OF ITCZ AXIS FROM 22W TO 35W.

...DISCUSSION...

GULF OF MEXICO...
VIGOROUS UPPER LEVEL TROUGH ACROSS ERN HALF OF CONUS SUPPORTS 
STRONG COLD FRONT PRESENTLY EXTENDING FROM FT MYERS FLORIDA TO 
NE YUCATAN PENINSULA CARRYING NUMEROUS STRONG CONVECTION WITHIN 
90 NM BOTH SIDES OF BOUNDARY.  STRONG N WINDS LITERALLY COVER 
ENTIRE SE HALF OF GULF WITH SEAS BUILDING TO 13-14 FT.  FRONT 
FORECAST TO MOVE OUT OF BASIN THIS AFTERNOON...BUT REINFORCED 
HIGH PRES 1029 MB BEHIND IT IS EXPECTED TO MAINTAIN TIGHT PRES 
GRADIENT SUPPORTING STRONG E BREEZE E OF 90W THROUGH MON NIGHT 
THEN SPREADING THROUGH ENTIRE GULF TUE.  VERY DRY SUBSIDING AIR 
MASS AT ALOFT CURTAIL ANY CONVECTION ONCE FRONT EXITS.  

CARIBBEAN SEA...
WITH THE EXCEPTION OF THE ADVECTING MOISTURE ASSOCIATED WITH 
ABOVE MENTIONED FRONT...CARIBBEAN REMAINS VERY DRY UNDER A 
STRONG SUBSIDING AIR MASS THAT COVERS THE ENTIRE BASIN TODAY.  
SUPPRESSION OF DEVELOPMENT EXPECTED TO AFFECT FRONTAL WEATHER 
TONIGHT AND MON SIGNIFICANTLY DIMINISHING ITS CONVECTION.  THESE 
CONDITIONS KEEP MOSTLY FAIR WEATHER CONDITIONS ELSEWHERE IN 
BASIN WITH STRONG TO NEAR GALE EASTERLY TRADES RULING E OF 80W.  
WINDS EXPECTED TO FURTHER STRENGTHEN TO GALE CONDITIONS MON 
NIGHT NEAR COAST OF COLOMBIA WITH SEAS BUILDING AS HIGH AS 15 
FT.  THERMAL LOW PRES 1008 MB OVER NW COAST OF COLOMBIA EXPECTED 
TO CONTRIBUTE TO STRENGTHEN THE WINDS.  LITTLE CHANGE IS 
FORECAST OVER BASIN THROUGH TUE.

ATLANTIC OCEAN...
HEALTHY COLD FRONT EXTEND FROM 31N79W TO 28N81W WITH NUMEROUS 
STRONG CONVECTION WITHIN 120 NM BOTH SIDES OF BOUNDARY.  
SATELLITE DETECTION SHOWS SOLID AREAS OF LIGHTNING STRIKES... 
BUT EXPECTED TO DIMINISH LATER THIS AFTERNOON AS FRONTAL ENERGY 
SHIFTS NE FOLLOWING UPPER LEVEL SUPPORT.  GALE FORCE WINDS WITH 
SEA HEIGHTS TO 13 FT EXPECTED N OF 27N ON BOTH SIDES OF FRONT 
THIS AFTERNOON AND TONIGHT. 

BROAD UPPER LEVEL RIDGE DOMINATE PATTERN ALOFT N OF 20N W OF 
50W.  SHARP AND DEEP TROUGH CUTS SW FROM 31N31W THROUGH LESSER 
ANTILLES...BOTH CONTRIBUTING TO KEEP VERY DRY AIR MASS ACROSS 
CENTRAL ATLC.  TROUGH ALSO HELPS IN ADVECTING ABUNDANT TROPICAL 
MOISTURE INTO UPPER LATITUDES E OF 20W.

SURFACE RIDGE AXIS STRETCHES FROM HIGH PRES CENTER 1035 MB NEAR 
IBERIAN PENINSULA AT 36N16W SW TO CENTRAL BAHAMAS.  STEADY FLOW 
OF FRESH TO STRONG E TO NE BREEZE ON SOUTHERN PERIPHERY OF RIDGE 
STRETCHES LONG FETCH AND PRODUCE LONG PERIOD SWELLS REACHING 11 
FT ACROSS MOST OF CENTRAL AND WESTERN N ATLC.  ONLY ISOLATED 
MODERATE SHOWERS EMBEDDED IN EASTERLY FLOW. 

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

$$

WALLY BARNES