000
AXNT20 KNHC 281745
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE APR 28 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
1715 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 4N8W 3N10W CROSSING THE EQUATOR 
AT 19W TO 2S30W AND INTO NE BRAZIL NEAR 3S40W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS FROM 1N-7N BETWEEN 
11W-17W.

...DISCUSSION...

GULF OF MEXICO...
A 1031 MB SURFACE HIGH IS LOCATED OVER THE W ATLC NEAR 33N73W 
AND EXTENDS A RIDGE ACROSS THE SE CONUS AND ENCOMPASSES FLORIDA 
AND MUCH OF THE GULF OF MEXICO. THIS FEATURE IS PRODUCING FRESH 
TO STRONG E TO SE FLOW ACROSS GULF REGION AS AN EARLIER QSCAT 
PASS FROM AROUND 1200 UTC CONFIRMED THESE WIND SPEEDS. THE 
SURFACE HIGH WILL REMAIN STATIONARY OVER THE NEXT 24 TO 36 HOURS 
WHILE GRADUALLY WEAKENING. ALOFT...A DEEP LAYERED TROUGH EXTENDS 
ACROSS THE CENTRAL GULF INTO SRN MEXICO. AN AREA OF STRONG 
SHOWERS AND TSTMS IS NOTED OVER ERN TEXAS ALONG A STATIONARY 
FRONTAL BOUNDARY...BUT THIS ACTIVITY IS FORECAST TO REMAIN 
INLAND N OF THE GULF. OTHERWISE ONLY A FEW ISOLATED SHOWERS ARE 
OBSERVED ACROSS THE SE GULF S OF 24N E OF 87W.

CARIBBEAN SEA...
HIGH PRESSURE LOCATED N OF AREA MAINTAINS FRESH TO STRONG 
SURFACE WIND ACROSS MUCH OF THE BASIN WITH THE STRONGEST WINDS 
IN THE TYPICAL AREA NEAR THE COAST OF COLOMBIA. THIS WEATHER 
PATTERN IS FORECAST TO PERSIST DURING THE NEXT 24 HOURS. THE 
HIGH IS FORECAST TO GRADUALLY WEAKEN TUE THROUGH FRI AND AS A 
RESULT... THE TRADE WINDS ARE EXPECTED TO DIMINISH DURING THIS 
TIME FRAME AS WELL. A BROAD UPPER LEVEL RIDGE COVERS MOST OF THE 
BASIN... WITH MOSTLY SW TO W UPPER LEVEL WINDS. THESE WINDS ARE 
ADVECTING MID/UPPER LEVEL MOISTURE FROM THE E PACIFIC REGION 
ACROSS N CENTRAL AMERICA INTO THE WRN CARIBBEAN SEA. IN 
ADDITION...LOW- TOPPED TRADE WIND SHOWERS ARE OBSERVED ACROSS 
THE REGION...MORE CONCENTRATED OVER THE NRN CARIBBEAN MAINLY N 
OF 16N. PATCHES OF LOW-LEVEL MOISTURE WILL CONTINUE TO PROPAGATE 
ACROSS THE BASIN PRODUCING ISOLATED TO SCATTERED PASSING 
SHOWERS. 

ATLANTIC OCEAN...
A 1031 MB SURFACE HIGH IS LOCATED IN THE W ATLC JUST N OF THE 
AREA NEAR 33N73W. THIS SYSTEM CONTINUES TO DOMINATE THE WEATHER 
ACROSS THE W ATLC AS A TIGHT PRESSURE GRADIENT WITH 20-25 KT ELY 
WINDS FROM 18N-27N W OF 60W INCLUDING THE BAHAMAS AND THE 
STRAITS OF FLORIDA IS OBSERVED. ISOLATED SHOWERS REMAIN EMBEDDED 
WITHIN THE ELY FLOW FROM THE NE CARIBBEAN INTO THE W ATLC TO 25N 
BETWEEN 65W-75W. THE REMAINDER OF THE DISCUSSION AREA IS UNDER 
THE INFLUENCE OF A RIDGE ANCHORED ON A 1028 MB HIGH CENTERED S 
OF THE AZORES NEAR 35N25W. A BELT OF FRESH TO STRONG NELY WINDS 
IS BETWEEN THE CANARY AND THE CAPE VERDE ISLANDS DUE TO THE 
TIGHT PRESSURE GRADIENT BETWEEN THIS HIGH AND LOWER PRESSURE 
OVER AFRICA. ALOFT...A LONG-WAVE TROUGH OVER THE E-CENTRAL ATLC 
ENTERS THE FORECAST AREA NEAR 32N38W THEN ALONG 30N TO 30N60W 
AND WESTWARD TO A CLOSED LOW LOCATED NEAR 30N73W NE OF THE 
BAHAMAS. THIS UPPER TROUGHING ALONG 30N SUPPORTS A DISSIPATING 
STATIONARY FRONTAL BOUNDARY CLIPPING THE REGION NEAR 32N58W TO 
BERMUDA GENERATING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF 
THE FRONT.

$$
HUFFMAN