000
AXNT20 KNHC 041041
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON MAY 04 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ALONG 6N10W 1N20W CROSSING THE EQUATOR NEAR 23W 
AND CONTINUING ALONG 1S30W 1S40W AND INTO NE BRAZIL NEAR 2S44W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM N 
OF THE AXIS BETWEEN 14W-25W. SIMILAR CONVECTION IS LOCATED FROM 
3S TO 3N BETWEEN 30W-36W.

...DISCUSSION...

GULF OF MEXICO...
THE COMBINATION OF BROAD SURFACE LOW PRESSURE ACROSS THE MEXICAN 
PLATEAU AND A SURFACE RIDGE EXTENDING FROM THE W ATLC ACROSS THE 
FLORIDA PENINSULA INTO THE NRN GULF IS PRODUCING SE WINDS FROM 
10 TO 20 KT. NO ORGANIZED AREAS OF DEEP CONVECTION ARE OCCURRING 
OVER THE GULF...HOWEVER A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH 
IS MOVING ACROSS THE SE CONUS AND IS SUPPORTING A STATIONARY 
FRONT ACROSS SRN ALABAMA...MISSISSIPPI...AND LOUISIANA THAT 
CONTINUES TO PRODUCE SCATTERED SHOWERS AND TSTMS INLAND OVER THE 
SE CONUS. A COLD FRONT IS ALSO POSITIONED ALONG THE IMMEDIATE 
TEXAS GULF COAST. THIS FRONT IS FORECAST TO BRUSH THE NW GULF 
WATERS OVER THE NEXT 24 HOURS BEFORE WEAKENING SLIGHTLY AND 
LIFTING NORTHWARD AS A STATIONARY BOUNDARY. UPPER LEVEL WINDS 
WILL CONTINUE TO TRANSITION TO MORE OVERALL ZONAL FLOW AS THE 
SHORTWAVE TROUGH LIFTS OFF TO THE NE. ONLY A FEW BANDS OF CIRRUS 
CLOUDS STRETCH ACROSS THE NE GULF ON DIFFLUENT FLOW LOCATED 
ACROSS THE ERN GULF AND FLORIDA.

CARIBBEAN SEA...
FRESH TRADEWINDS REMAIN ACROSS THE CARIBBEAN AS THE ANALYZED 
PRESSURE FIELD CONTINUES TO EXHIBIT A RELATIVELY RELAXED 
GRADIENT. A SURFACE TROUGH EXISTS IN THE ERN CARIBBEAN EXTENDING 
FROM THE U.S. VIRGIN ISLANDS SWD ALONG 65W TO THE NE COAST OF 
VENEZUELA. SCATTERED SHOWERS ARE AFFECTING THE LESSER ANTILLES 
AND NE CARIBBEAN MAINLY N OF A SAINT LUCIA TO WRN PUERTO RICO 
LINE...AS OBSERVED FROM THE GUADELOUPE...MARTINIQUE AND PUERTO 
RICO RADARS. ELSEWHERE...AN UPPER LEVEL HIGH CENTERED OVER NRN 
COLOMBIA EXTENDS RIDGING TO THE NW ACROSS CENTRAL AMERICA AS FAR 
N AS BELIZE AND GUATEMALA. UPPER DIFFLUENCE IS GENERATING A FEW 
ISOLATED SHOWERS AND TSTMS ACROSS THE SW CARIBBEAN S OF 11N WITH 
MORE SCATTERED ACTIVITY INLAND ACROSS NRN SOUTH AMERICA. DEBRIS 
MOISTURE FROM THE CONVECTION OVER COLOMBIA AND VENEZUELA...IN 
THE FORM OF SCATTERED CIRRUS CLOUDS...IS SPREADING NE ACROSS 
MUCH OF THE CARIBBEAN.

ATLANTIC OCEAN...
THE ATLANTIC IS DOMINATED BY A SURFACE HIGH PRESSURE CENTERED 
WELL NORTH OF THE DISCUSSION AREA NEAR 46N21W WITH RIDGING 
EXTENDING WEST-SOUTHWESTWARD TO 34N54W AND TO THE FLORIDA 
PENINSULA. TWO SMALLER SCALE FEATURES ARE OF INTEREST WHICH ARE 
EMBEDDED WEAKNESSES WITHIN THE SURFACE RIDGE. THE FIRST IS A 
SURFACE TROUGH NE OF PUERTO RICO ALONG 69W FROM ROUGHLY 21N TO 
29N. THIS TROUGH HAS BEEN PROGRESSING W-NW WITH A MIDDLE TO 
UPPER LEVEL LOW OBSERVED ON WATER VAPOR IMAGERY W OF THE SURFACE 
TROUGH CENTERED NEAR 28N70W. SCATTERED SHOWERS AND ISOLATED 
TSTMS ARE PRESENT WITHIN 90 NM OF A LINE FROM 21N62W TO 28N69W. 
THE SURFACE WINDS ARE ENHANCED E OF THE TROUGH AXIS WITH E TO SE 
WINDS OF UP TO 25 KT. THE SECOND FEATURE IS A SURFACE TROUGH 
EXTENDING FROM 25N38W TO BEYOND 32N43W. SCATTERED SHOWERS ARE 
OCCURRING E OF THE SURFACE TROUGH FROM 28N-34N BETWEEN 35W-41W. 
A BROAD UPPER LOW CENTERED NEAR 31N38W ASSOCIATED WITH THE 
SURFACE TROUGH DOMINATES THE UPPER LEVEL WINDS OVER MOST OF THE 
CENTRAL ATLC WITH CYCLONICALLY TURNING WINDS OBSERVED AS FAR S 
AS 10N. FINALLY...THERE IS AN ENHANCEMENT OF NELY SURFACE WINDS 
OF 20-25 KT NORTHEAST OF THE CAPE VERDE ISLANDS TO THE WEST 
COAST OF MAURITANIA AND SENEGAL. OVER THE NEXT FEW DAYS...THE 
SURFACE TROUGH N OF PUERTO RICO IS FORECAST TO CONTINUE MOVING 
NORTHWESTWARD...WHILE THE TROUGH IN THE CENTRAL ATLANTIC SHOULD 
GRADUALLY FILL.

$$
HUFFMAN