000
AXNT20 KNHC 081743
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
205 PM EDT FRI APR 08 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 ALONG 04N08W 02N18W CROSSING THE EQUATOR NEAR 26W 
THEN INTO NE BRAZIL NEAR 02S44W. ISOLATED MODERATE CONVECTION IS 
FROM 01N-05N BETWEEN 10W-17W...AND FROM 01N-06N BETWEEN 26W-38W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES A MIDDLE TO UPPER LEVEL RIDGE OVER 
MUCH OF THE GULF THIS AFTERNOON ACCOMPANIED BY MOSTLY DRY AIR 
AND OVERALL SUBSIDENCE. THIS UPPER LEVEL FEATURE CONTINUES TO 
SUPPORT A SURFACE RIDGE AXIS WHICH EXTENDS FROM THE W ATLC NEAR 
30N71W ACROSS THE CENTRAL FLORIDA PENINSULA TO THE WEST-CENTRAL 
GULF NEAR 24N94W. LOCATED MOSTLY ON THE WESTERN PERIPHERY OF THE 
RIDGE...SOUTHERLY RETURN FLOW IN THE RANGE OF 10 TO 20 KT IS 
EXPECTED THROUGH EARLY SUNDAY...WITH THE STRONGEST WINDS TO 20 
KT MAINLY W OF 90W. WINDS OVER THE NW GULF WILL VEER SLIGHTLY ON 
SUNDAY WITH A WEAK COLD FRONT FORECAST TO EMERGE OFF THE TEXAS 
AND LOUISIANA GULF COAST EARLY MONDAY.

CARIBBEAN SEA...
THE CARIBBEAN SEA REMAINS UNDER MOSTLY WEST-SOUTHWESTERLY UPPER 
LEVEL FLOW DUE TO AN UPPER LEVEL RIDGE AXIS THAT EXTENDS FROM 
THE TROPICAL NORTH ATLC NEAR 05N40W OVER NORTHERN VENEZUELA NEAR 
09N66W THEN TO BEYOND GUATEMALA NEAR 15N91W. MOSTLY DRY AIR AND 
SUBSIDENCE IS ASSOCIATED WITH THIS RIDGE MAINLY N OF 13N. AT THE 
SURFACE...EASTERLY TRADES CONTINUE AND ARE EXPECTED TO PERSIST 
THROUGH THE WEEKEND DUE TO A STATIONARY RIDGE LOCATED IN THE SW 
NORTH ATLC. LOW-LEVEL MOISTURE CONTINUES TO ADVECT WESTWARD 
ACROSS THE BASIN WITH ISOLATED SHOWERS NOTED ON VISIBLE 
SATELLITE IMAGERY OVER PORTIONS OF THE NORTH-CENTRAL AND NE 
CARIBBEAN WITHIN 120 NM EITHER SIDE OF A LINE FROM 14N61W TO 
17N66W TO 19N82W. SCATTERED SHOWERS AND TSTMS ARE ALSO OCCURRING 
IN THE SW CARIBBEAN S OF 11N...LIKELY ENHANCED BY UPPER LEVEL 
DIFFLUENCE ASSOCIATED WITH THE RIDGING ALOFT.

ATLANTIC OCEAN...
UPPER LEVEL TROUGHING IS LOCATED OVER THE WESTERN NORTH ATLC AND 
DIPS INTO THE DISCUSSION AREA TO 24N BETWEEN 45W-65W. AN UPPER 
LEVEL SHORTWAVE TROUGH IS EMBEDDED WITHIN THE MEAN TROUGH IN THE 
VICINITY OF 50W AND SUPPORTS A COLD FRONT ANALYZED INTO THE 
REGION NEAR 32N41W THAT EXTENDS SW TO 25N57W THEN MEANDERS 
W-SW TO 24N67W. WHILE STRONG UPPER LEVEL DYNAMICS LACK IN 
VICINITY OF THE FRONT...ISOLATED SHOWERS ARE OCCURRING WITHIN 90 
NM E OF THE FRONT N OF 27N. A 1023 MB HIGH IS CENTERED W-NW OF 
THE FRONT NEAR 30N71W THAT IS PROVIDING MOSTLY FAIR WEATHER 
CONDITIONS OVER MUCH OF THE SW NORTH ATLC N OF 25N W OF 55W. 
FARTHER EAST...THE REMAINDER OF THE EASTERN ATLC IS UNDER THE 
INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1024 MB HIGH CENTERED 
NEAR 27N34W PROVIDING MOSTLY FAIR WEATHER CONDITIONS E OF 
AFOREMENTIONED COLD FRONT.

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

$$
HUFFMAN