000
AXNT20 KNHC 192310
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU APR 19 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2245 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N9W 5N18W 2N32W ALONG THE EQUATOR 
FROM 44W-52W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 
90/120 NM S OF THE ITCZ AXIS FROM 12W-18W AND WITHIN 60/75 NM OF 
A LINE FROM 1.5N4W TO 3N10W. 

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE COVERS MUCH OF THE GULF EXTENDING FROM SOUTH 
AMERICA ACROSS THE CARIBBEAN AND CENTRAL AMERICA TO OVER TEXAS 
AND OKLAHOMA. THIS IS ADVECTING TROPICAL MOISTURE ACROSS MEXICO 
AND OVER THE W GULF MOSTLY IN THE UPPER LEVELS. WEAK COLD FRONT 
EXTENDS THROUGH THE STRAITS OF FLORIDA NEAR 25N80W TO 23N83W. 
THIS FRONT IS ASSOCIATED WITH A BROAD UPPER TROUGH THAT COVERS 
THE NE US INTO THE W ATLC AND THE GULF E OF 84W. DRY UPPER AIR 
OVER FLORIDA IS LIMITING SHOWERS BUT LENDING TO THE FIRES 
CURRENTLY BURNING IN THE EVERGLADES. LIGHT N TO WINDS DOMINATE 
THE ENTIRE AREA. WEAK RIDGE IS BUILDING S FROM OVER THE E US  
ENCOMPASSING THE GULF AND SHALL REMAIN THROUGH THE WEEKEND. 

CARIBBEAN SEA...
BROAD UPPER RIDGE DOMINATES THE ENTIRE AREA ANCHORED INLAND OVER 
SOUTH AMERICA WITH THE AXIS EXTENDING ALONG 10N70W INTO THE GULF 
OF MEXICO NEAR 21N87W. WEAK 1007 MB LOW IS INLAND OVER NW 
VENEZUELA GENERATING SHOWER/THUNDERSTORMS INLAND AND WITHIN 
45/60 NM ALONG THE COAST OF VENEZUELA AND COLOMBIA FROM 69W-76W. 
THE REMAINDER OF THE CARIBBEAN REMAINS CLEAR TO THE DRY AIR IN 
PLACE OVER THE ENTIRE AREA. 

ATLANTIC OCEAN...
THE DEEP LAYERED TROUGH OVER THE E US AND FLORIDA CONTINUES TO 
MOVE ACROSS THE W AND CENTRAL ATLC N OF 20N E OF 50W. THE MOST 
SIGNIFICANT FEATURE AGAIN TONIGHT IS THE LARGE 989 MB LOW WELL N 
OF THE REGION WITH A WEAKENING FRONTAL BOUNDARY THAT DOES NOT 
EXTEND INTO THE REGION. HOWEVER...EMBEDDED WITHIN THE BROAD 
UPPER RIDGE IS A WEAK SHORTWAVE UPPER TROUGH JUST SW OF BERMUDA 
WITH THE ASSOCIATED COLD FRONT EXTENDING FROM A 1004 MB LOW NEAR 
30N72W ACROSS THE N BAHAMAS AND THROUGH THE FLORIDA STRAITS NEAR 
25N80W. DIFFLUENCE TO THE E OF THE BROAD UPPER TROUGH IS 
ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 
120/150 NM OF A LINE FROM 22N54W TO BEYOND 32N42W. DRY AIR 
COVERS THE W ATLC LIMITING ANY SHOWER ACTIVITY WITH THE FRONT 
OVER THE BAHAMAS. HIGH PRESSURE COVERS THE E ATLC WITH A 1021 MB 
HIGH LOCATED NEAR 30N31W. DRY AIR DOMINATES THE E ATLC AS WELL 
AS THE TROPICAL ATLC...LIMITING SHOWER ACTIVITY AND PUSHING THE 
ITCZ TO THE S.  

$$
WALLACE