000
AXNT20 KNHC 040457
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED APR 4 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 
SECTIONS OF SOUTH AMERICA...AND THE 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0345 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N10W 3N2OW 1N23W CROSSING THE 
EQUATOR NEAR 30W TO 1S40W AND INTO SOUTH AMERICA NEAR 1S51W. A 
WEAK SURFACE TROUGH IS EMBEDDED IN THE ITCZ BETWEEN 3N20W AND 
1N23W WITH ISOLATED SHOWERS WITHIN 120 NM OF THE TROUGH. 
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE 
WITHIN 150 NM ALONG THE COAST OF SOUTH AMERICA N OF 2N E OF 53W. 

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE EXTENDING FROM WESTERN CUBA THROUGH THE SE 
US CONTINUES TO DOMINATE THE GULF ADVECTING UPPER LEVEL MOISTURE 
FROM THE E PACIFIC ACROSS MEXICO INTO THE GULF AND THE SE US. A 
SHORT WAVE TROUGH OVER NW MEXICO IS MOVING SLOWLY E IS ENHANCING 
HEAVY SHOWERS/THUNDERSTORMS MAINLY OVER MEXICO AND S TEXAS. 
ASSOCIATED WITH THE SHORTWAVE TROUGH IS A FRONTAL BOUNDARY 
EXTENDING WELL INLAND OVER TEXAS ACROSS THE MISSISSIPPI VALLEY 
TO ACROSS THE N ALABAMA. A WEAK SURFACE HIGH OVER FLORIDA IS 
PRODUCING WEAK S TO SE WINDS OVER THE ENTIRE GULF.  

CARIBBEAN SEA...
A BROAD UPPER E/W RIDGE EXTENDS ACROSS THE N PORTION OF SOUTH 
AMERICA WITH SE WIND TRANSPORTING UPPER LEVEL MOISTURE ACROSS 
CENTRAL AMERICA AND THE NW PORTION OF THE CARIBBEAN. A 1019 MB 
SFC HIGH SITUATED NORTH OF THE AREA CONTINUES TO PRODUCE 
MODERATE TO STRONG TRADE WINDS ACROSS THE BASIN. A NARROW BAND 
OF HIGH CLOUDS IS JUST SOUTH OF THE GREATER ANTILLES ON THE 
NORTHERN PERIPHERY OF THE BROAD UPPER RIDGE. 

ATLANTIC OCEAN...
AN UPPER RIDGE/TROUGH/RIDGE PATTERN CONTINUES TO DOMINATE THE 
FORECAST AREA. BROAD UPPER RIDGE THAT COVERS THE CARIBBEAN AND 
GULF OF MEXICO EXTEND INTO THE W ATLC W OF 65W. A SURFACE RIDGE 
COVERS THE W ATLC S OF 30N W OF 55W INTO THE GULF OF MEXICO 
ANCHORED BY A 1019 MB HIGH N OF THE BAHAMAS NEAR 28N77W. A DEEP 
LAYERED TROUGH IS IN THE CENTRAL ATLC N OF 15N FROM 35W-66W WITH 
THE A SERIES OF UPPER LOWS WELL N OF THE REGION. THE ASSOCIATED 
LEADING COLD FRONT ENTERS THE E ATLC NEAR 32N25W EXTENDING SSW 
TO 21N36W CONTINUING AS A SURFACE TROUGH ALONG 14N43W TO 13N51W. 
A DEEPENING 1004 MB LOW CENTERED E OF BERMUDA NEAR 43N56W 
EXTENDS A RE-ENFORCING COLD FRONT INTO THE W/CENTRAL ATLC ALONG 
30N59W THEN NE TO 31N66W DISSIPATING AS A STATIONARY BOUNDARY 
ALONG THE CAROLINA COAST. THIS SYSTEM IS EXPECTED TO CONTINUE TO 
DEEPEN AND DROP SE INTO THE N PORTION OF THE CENTRAL ATLC LATER 
TODAY INCREASING SHOWER ACTIVITY WITH ASSOCIATED STRONGER WINDS 
AND HIGH SEAS TO WELL WITHIN THE AREA. SCATTERED SHOWERS/ 
ISOLATED THUNDERSTORMS ARE WITHIN 120 NM SE OF THE COLD FRONT. 
THE LEADING COLD FRONT IS EMBEDDED WITHIN AN AREA OF MODERATE/ 
STRONG SUBSIDENCE AND DRY UPPER AIR LIMITING ACTIVITY TO 
ISOLATED SHOWERS WITHIN 75 NM E OF THE FRONT. BROAD E/W UPPER 
RIDGE COVERS THE TROPICAL ATLC EXTENDING FROM AFRICA ACROSS THE 
ATLC TO SOUTH AMERICA WITH THE AXIS ROUGHLY ALONG 7N/8N THUS 
SUPPRESSING THE ITCZ AXIS TO THE S. THIS SAME UPPER RIDGE 
EXTENDS N ALONG THE COAST OF AFRICA TO OVER THE CANARY ISLANDS. 

$$
WADDINGTON/WALLACE