000
AXNT20 KNHC 272342
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON APR 27 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 5N9W 2N20W CROSSING THE EQUATOR 
AT 25W TO 2S35W INTO NE BRAZIL NEAR 3S46W. CLUSTERS OF MODERATE 
TO STRONG CONVECTION ARE NOTED OVER SW AFRICA AND NE BRAZIL. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM THE 
EQUATOR TO THE COAST OF AFRICA BETWEEN 3W-6W. 

...DISCUSSION...

GULF OF MEXICO...
A LARGE 1032 MB SURFACE HIGH LOCATED OVER THE W ATLC NEAR 33N73W 
EXTENDS A RIDGE ACROSS THE FLORIDA STATE INTO THE ENTIRE GULF OF 
MEXICO. THIS FEATURE IS PRODUCING FRESH TO STRONG E TO SE FLOW 
ACROSS GULF REGION. AN ASCAT PASS FROM AROUND 1600 UTC CONFIRMED 
THESE WIND SPEEDS. THE SFC HIGH WILL REMAIN STATIONARY OVER THE 
NEXT 24 TO 36 HOURS WHILE GRADUALLY WEAKENING. ALOFT...A DEEP 
LAYERED TROUGH EXTENDS ACROSS CENTRAL TEXAS AND NE MEXICO. AN 
AREA OF STRONG SHOWERS AND TSTMS IS NOTED OVER TEXAS AHEAD OF 
FRONT AND DRY LINE COMPLEX...BUT THIS ACTIVITY SHOULD REMAIN N 
OF THE GULF. SOME SHOWER/TSTM ACTIVITY IS ALSO NOTED OVER NE 
MEXICO... PARTICULARLY OVER THE STATE OF COAHUILA. OTHERWISE A 
SHARP MID/UPPER LEVEL RIDGE EXTENDS FROM THE BAY OF CAMPECHE TO 
THE SE CONUS. A NARROW BAND OF MID/UPPER LEVEL MOISTURE IS 
BETWEEN THE TROUGH AND THE RIDGE AND GOES FROM CENTRAL MEXICO TO 
SE LOUISIANA. GENERALLY SCATTERED CLOUDS PERSIST OVER THE 
AREA... EXCEPT FOR BROKEN LOW CLOUDS NEAR THE TEXAS COAST.

CARIBBEAN SEA...
HIGH PRES 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 
WILL PERSIST DURING THE NEXT 24 HOURS. THE HIGH IS FORECAST TO 
GRADUALLY WEAKEN TUE THROUGH FRI. AS A RESULT...THE TRADE WINDS 
ARE EXPECTED TO DIMINISH DURING THIS TIME-FRAME. A BROAD UPPER 
LEVEL RIDGE COVERS MOST OF THE CARIBBEAN...WITH MOSTLY SW TO W 
UPPER LEVEL WINDS. THESE WINDS ARE TRANSPORTING ABUNDANT 
MID/UPPER LEVEL MOISTURE FROM THE EPAC REGION ACROSS N CENTRAL 
AMERICA INTO THE CARIBBEAN SEA...THEN OVER E CUBA...JAMAICA AND 
HISPANIOLA. A SHORT-WAVE TROUGH IS OVER WESTERN CUBA AND THE NW 
CARIBBEAN. THIS TROUGH IS HELPING TO INDUCE SOME SHOWER/TSTM 
ACTIVITY OVER CUBA. IN ADDITION...LOW-TOPPED TRADE WIND SHOWERS 
ARE OBSERVED ACROSS THE REGION...MORE CONCENTRATED OVER THE 
EASTERN CARIBBEAN AND JAMAICA. PATCHES OF LOW-LEVEL MOISTURE 
WILL CONTINUE TO PROPAGATE ACROSS THE CARIBBEAN SEA PRODUCING 
ISOLATED TO SCATTERED PASSING SHOWERS. 

ATLANTIC OCEAN...
AS PREVIOUSLY MENTIONED...A LARGE 1032 MB SURFACE HIGH IS JUST N 
OF THE AREA NEAR 33N73W. THIS SYSTEM HAS TIGHTENED THE PRES 
GRADIENT OVER THE W ATLC WITH 20-25 KT ELY WINDS FROM 20N-27N W 
OF 63W INCLUDING THE BAHAMAS AND THE STRAITS OF FLORIDA. A SFC 
TROUGH...REMNANTS OF A FRONTAL BOUNDARY...IS ANALYZED ALONG 
31N47W 27N51W 24N52W. ISOLATED SHOWERS ARE JUST AHEAD OF THE 
TROUGH AXIS MAINLY NEAR 27N51W. THE REMAINDER OF THE DISCUSSION 
AREA IS UNDER THE INFLUENCE OF A RIDGE ANCHORED ON A HIGH NEAR 
THE AZORES. A BELT OF FRESH TO STRONG NLY WINDS IS BETWEEN THE 
CANARY AND THE CAPE VERDE ISLANDS DUE TO THE TIGHT PRES GRADIENT 
BETWEEN THIS HIGH AND LOWER PRES OVER AFRICA. A LONG-WAVE TROUGH 
OVER THE E-CENTRAL ATLC ENTERS THE FORECAST AREA NEAR 31N45W TO 
A CLOSED LOW LOCATED 29N48W...THEN THE TROUGH EXTENDS MAINLY E-W 
TO ANOTHER CLOSED LOW LOCATED NE OF THE BAHAMAS NEAR 30N70W. 
THIS UPPER-LEVEL PATTERN IS FORECAST TO PERSIST OVER THE NEXT 
COUPLE OF DAYS WITH THE WESTERNMOST UPPER LOW MOVING EWD AND THE 
ASSOCIATED TROUGH DIGGING SWD INTO THE NORTHERN CARIBBEAN. 
COMPUTER MODEL ALREADY ANTICIPATES AN INCREASE IN MOISTURE 
ACROSS THE GREATER ANTILLES FROM EASTERN CUBA TO PUERTO RICO AND 
OVER THE SE BAHAMAS DUE TO THE PRESENCE OF THIS UPPER-LEVEL 
TROUGH.    

$$
GR