000
AXNT20 KNHC 212305
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED MAR 21 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 
2215 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N10W JUST S OF THE EQUATOR FROM 
22W-35W THEN ALONG 3N45W 2N52W. SCATTERED MODERATE/STRONG 
CONVECTION IS FROM 4N TO S OF THE EQUATOR BETWEEN 18W-27W. 
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 150/200 NM 
OF THE AXIS FROM 27W-43W.  

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER LEVEL RIDGE IS MOVING FROM THE E PACIFIC REGION 
ACROSS MEXICO AND THE CENTRAL PLAIN STATES RE-ENFORCING THE 
UPPER RIDGE CURRENTLY OVER THE GULF. A WEAK SHORTWAVE UPPER 
TROUGH IS OVER THE MISSISSIPPI VALLEY BUT IS NOT IN THE GULF. 
THE BROAD UPPER LEVEL OVER THE W ATLC EXTENDS FROM OVER FLORIDA 
EASTWARD. STRONG SURFACE E TO SE WINDS CONTINUE TO DOMINATE THE 
GULF WITH SURFACE RIDGE ANCHORED IN THE W ATLC AND THE RIDGE 
AXIS EXTENDING INTO THE GULF FROM OVER GEORGIA SW TO THE BAY OF 
CAMPECHE. UPPER LEVEL MOISTURE REMAINS OVER THE N GULF WITH 
MODERATE SUBSIDENCE AND DRY AIR IN THE LOWEST LEVELS CONTINUING 
TO KEEP THE MUCH OF THE GULF UNDER MOSTLY CLEAR SKIES. HOWEVER 
WITH THE STRONG EASTERLY SURFACE FLOW IS USHERING IN SCATTERED 
SHOWERS/ISOLATED THUNDERSTORMS OVER THE FLORIDA PENINSULA AND 
THE IMMEDIATE COASTAL WATERS. SIMILAR ACTIVITY IS N OF 28N FROM 
88W-92W ASSOCIATED WITH THE UPPER TROUGH OVER THE MISSISSIPPI 
VALLEY. 

CARIBBEAN...
THE CARIBBEAN IS DOMINATED BY A BROAD UPPER RIDGE ANCHORED IN 
THE TROPICAL ATLC GIVING MOST THE AREA SW TO W UPPER FLOW. THE 
REMNANTS OF THE FRONTAL BOUNDARY OF A FEW DAYS AGO CONTINUES TO 
GIVE THE N/CENTRAL CARIBBEAN SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS ARE N OF 16N FROM 72W-80W. THE MOSITURE LEVELS 
HAVE INCREASED OVER THE PAST 24 TO 48 HOURS INCREASING THE 
CHANCE OF SCATTERED SHOWERS ACROSS THE AREA EXCEPT ALONG THE 
COAST OF SOUTH AMERICA. STRONG EASTERLY TRADE WINDS CONTINUE 
ACROSS THE ENTIRE CARIBBEAN WITH THE STRONGEST WINDS ALONG THE 
COAST OF COLOMBIA. 
 
ATLANTIC...
BROAD UPPER TROUGH COVERS THE W ATLC EXTENDING FROM OVER FLORIDA 
TO 60W. THE ASSOCIATED STATIONARY FRONT ENTERS THE AREA NEAR 
32N54W EXTENDING SSW ALONG 24N62W. OVERCAST CLOUDS WITH EMBEDDED 
SHOWERS/ISOLATED THUNDERSTORMS ARE W OF THE FRONT WITHIN 120/150 
NM OF LINE 26N63W TO THE CENTRAL BAHAMAS NEAR 25N76W. STRONG 
EASTERLY SURFACE FLOW IS USHERING IN SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS OVER THE FLORIDA PENINSULA AGAIN THIS AFTERNOON.  
BROAD UPPER LEVEL LOW COVERS THE E ATLC N OF 16NE OF 40W 
CENTERED NEAR 30N28W. LARGE SURFACE RIDGE COVERS THE ATLC WITH A 
WEAKNESS IN THE IMMEDIATE VICINITY OF THE STATIONARY FRONT. THE 
TROPICAL ATLC IS DOMINATED BY A BROAD UPPER RIDGE COVERS THE 
CARIBBEAN/W TROPICAL ATLC AND SECOND E/W RIDGE ANCHORED INLAND 
OVER AFRICA. 

$$
WALLACE