000
AXNT20 KNHC 021728
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT MAY 02 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
1330 UTC.

...THE ITCZ...

THE ITCZ AXIS EXTENDS FROM W AFRICA AT 05N08W TO THE EQUATOR AT 
25W TO NE BRAZIL NEAR 04S39W. SCATTERED MODERATE CONVECTION IS 
WITHIN 120 NM OF THE ITCZ.  

...DISCUSSION...

GULF OF MEXICO...
SOUTHEASTERLY SURFACE WINDS OF 10-20 KT PREVAIL ACROSS THE GULF 
OF MEXICO...THE HIGHER VALUES IN THE WESTERN GULF...UNDER THE 
INFLUENCE OF A RIDGE OF HIGH PRESSURE NORTHEAST OF FLORIDA AND A 
BROAD LOW OVER TEXAS.  THERE ARE NO AREAS OF ORGANIZED DEEP 
CONVECTION AT THIS TIME.  IN THE UPPER LEVELS...A WEAK TROUGH 
LIES ACROSS THE GULF WITH SUBSIDING STABLE CONDITIONS 
DOMINATING.  LITTLE CHANGE IS ANTICIPATED FOR MOST OF THE GULF 
IN THE NEXT TWO DAYS...THOUGH THE BAROCLINIC SYSTEM OVER TEXAS 
MAY SEE THE COOL FRONTAL BOUNDARY JUST REACHING THE EXTREME NW 
GULF MONDAY MORNING.  IF IT DOES...THEN THIS PORTION OF THE GULF 
MAY SEE INCREASED CHANCES FOR PRECIPITATION AND A RELATIVELY 
BRIEF SWING OF THE SURFACE WINDS TO A NORTHERLY COMPONENT.

CARIBBEAN SEA...
EAST TO NORTHEASTERLY SURFACE WINDS RANGING FROM 10 TO 25 KT ARE 
OCCURRING TODAY...SOUTH OF THE RIDGE OVER THE WESTERN ATLANTIC.  
THE STRONGEST WINDS JUST SOUTH OF HISPANIOLA AND NORTH OF 
COLUMBIA ARE WELL-DEPICTED BY THE 1042 UTC QUIKSCAT PASS.  A 
SURFACE TROUGH EXTENDS FROM THE LESSER ANTILLES 
NORTH-NORTHEASTWARD INTO THE ATLANTIC.  THIS TROUGH IS KICKING 
UP SCATTERED LOW-TOPPED PRECIPITATION IN THE LESSER ANTILLES AS 
DEPICTED BY THE GUADELOUPE AND MARTINIQUE RADARS.  ADDITIONAL 
SHALLOW CONVECTION IS SEEN FROM THE VISIBLE SATELLITE IMAGERY 
JUST SOUTHWEST OF HAITI...LIKELY DUE TO THE CONVERGENCE OF 
SURFACE WINDS ON THE LEE SIDE OF HISPANIOLA.  IN THE UPPER 
LEVELS...ANTICYCLONICALLY TURNING WINDS WITH GENERAL SUBSIDENCE 
PREVAIL.  UPPER LEVEL CLOUDINESS IS BEING SPREAD EASTWARD BY 
THESE WINDS FROM CONVECTION OCCURRING OVER SOUTH AMERICA AND THE 
NORTHEAST PACIFIC'S ITCZ.

ATLANTIC OCEAN...
THE MAIN PLAYER TODAY IS THE VERY LARGE SURFACE HIGH CENTERED 
NORTH OF THE AZORES WITH THE RIDGE LINE EXTENDING SOUTHWESTWARD 
FROM THE HIGH TO 32N64W TO THE FLORIDA PENINSULA.  EASTERLY 
WINDS OF 20 KT OR LESS AND NO AREAS OF DEEP CONVECTION...WITH 
ONE EXCEPTION... COVER THE ATLANTIC.  THE ONLY EXCEPTION TO THE 
BENIGN CONDITIONS IS THE PROMINENT AFOREMENTIONED SURFACE TROUGH 
THAT EXTENDS FROM THE LESSER ANTILLES NORTH-NORTHEASTWARD TO 
25N58W.  THE TROUGH IS ASSOCIATED WITH A MID LEVEL LOW CENTERED 
NEAR 25N55W...WHICH CAN BE SEEN IN THE WATER VAPOR IMAGERY.  
SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 180 NM EAST OF 
THE SURFACE TROUGH NORTH OF 23N...THOUGH IT HAS BEEN DIMINISHING 
TODAY.  ISOLATED SHOWERS ARE ALSO OCCURRING OVER THE LESSER 
ANTILLES AND WITHIN 300 NM EAST OF THE TROUGH AXIS.  THE TROUGH 
IS ANTICIPATED TO SLOWLY WEAKEN AS IT MOVES GRADUALLY TO THE 
WEST.  ELSEWHERE...A WEAK COLD FRONT HAS REACHED OUR NORTHERN 
BOUNDARY EXTENDING FROM 32N39W TO 29N41W.  IT IS POSSIBLE AN 
EXTENSION OF THIS BOUNDARY EXISTS FROM THAT POINT WESTWARD ALONG 
29N TO ABOUT 50W.  SCATTERED SHOWERS ARE OBSERVED WITHIN 60 NM 
OF THE FRONT.  IN THE UPPER LEVELS...CYCLONICALLY CURVING 
WESTERLIES PREVAIL WITH PEAK WINDS AT 200 MB AROUND 70 KT 
BETWEEN 20-30N EAST OF 45W.  WIDESPREAD CIRRUS IS BEING ADVECTED 
NORTHEASTWARD IN THIS FLOW.

$$
LANDSEA