000
AXNT20 KNHC 182306
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN MAR 18 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.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N6W 4N14W 2N29W 2N47W CROSSING 
EQUATOR NEAR 37W NEAR 52W. SCATTERED STRONG CONVECTION IS WITHIN 
A 60/75 NM RADIUS OF 1.5N9W. CLUSTERS OF SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 5N TO THE EQUATOR 
BETWEEN 18W-28W AND WITHIN 120 NM ALONG THE SW COAST OF AFRICA 
FROM 2W-7W. 

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL RIDGE IS MOVING ACROSS MEXICO AND THE CENTRAL PLAIN 
STATES INTO THE W GULF. THE BROAD UPPER LEVEL TROUGH REMAINS 
OVER THE E US AND THE REMAINDER OF THE GULF OF MEXICO EXTENDING 
INTO THE W ATLC. STRONG WINDS E TO SE WINDS DOMINATE THE GULF 
WITH SURFACE RIDGE ANCHORED OVER THE E US WITH A 1027 MB HIGH 
LOCATED OVER THE W FLORIDA PANHANDLE. IN THE WAKE OF THE MOST 
RECENT FRONTAL PASSAGE IS STRONG SUBSIDENCE AND DRY AIR AT ALL 
LEVELS GIVING THE GULF WITH CLEAR SKIES AND MILDER TEMPERATURES. 
HIGH PRESSURE WILL REMAIN IN CONTROL OF THE GULF THROUGH WED.

CARIBBEAN...
THE BROAD UPPER TROUGH OVER THE GULF OF MEXICO AND THE W ATLC 
COVERS THE NW CARIBBEAN WITH A REMNANT SURFACE TROUGH REMAINING 
FROM OVER HAITI ALONG THE E COAST OF JAMAICA TO 14N80W...HOWEVER 
IT IS LOSING ITS IDENTITY. STRONG SUBSIDENCE AND DRY AIR AT ALL 
LEVELS ARE BEHIND THE FRONT LEAVING THE AREA W OF THE FRONT WITH 
ONLY SCATTERED COLD AIR STRATOCUMULUS CLOUDS. THE REMAINDER OF 
THE CARIBBEAN IS DOMINATED BY A BROAD UPPER RIDGE ANCHORED ALONG 
THE COAST OF SOUTH AMERICA NEAR 7N58W AND EXTENDS ACROSS THE 
TROPICAL ATLC TO 40W. THIS IS ADVECTING SOME TROPICAL MOISTURE 
ACROSS THE E CARIBBEAN WITH THE SCATTERED THUNDERSTORMS 
DEVELOPING OVER COLOMBIA AND ALONG THE IMMEDIATE COASTAL WATERS. 
 
ATLANTIC...
BROAD UPPER TROUGH THAT COVERS E US AND THE GULF OF MEXICO 
EXTENDS OVER THE W ATLC TO 60W WITH THE ASSOCIATED COLD FRONT 
ENTERING THE AREA NEAR 32N59W CONTINUING ALONG 26N65W TO OVER 
HAITI NEAR 19N72W. BROKEN/OVERCAST CLOUDS WITH EMBEDDED 
RAIN/ISOLATED THUNDERSTORMS ARE WITHIN 300 NM E OF THE FRONT N 
OF 26N AND WITHIN 200 NM E OF THE FRONT S OF 26N TO OVER 
HISPANIOLA. IN THE WAKE OF THE COLD FRONT...STRONG SUBSIDENCE 
AND DRY AIR AT ALL LEVELS DOMINATE THE AREA WITH ONLY BROKEN 
COLD AIR STRATOCUMULUS CLOUDS. BROAD UPPER LEVEL TROUGH COVERS 
THE E ATLC N OF 20N E OF 45W WITH THE UPPER LOW N OF THE CANARY 
ISLANDS. HOWEVER...THERE IS NO LONGER A SURFACE REFLECTION. A 
SURFACE RIDGE COVERS THE E ATLC EXTENDING FROM A 1044 MB HIGH N 
OF THE AZORES THROUGH 32N38W TO 16N50W. THE TROPICAL ATLC IS 
DOMINATED BY A BROAD UPPER RIDGE THAT EXTENDS S OF 20N W OF 40W 
TO OVER THE CARIBBEAN AND SECOND E/W RIDGE ANCHORED OVER AFRICA. 

$$
WALLACE