000
AXNT20 KNHC 131027
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE MAR 13 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 5N8W 3N20W 4N31W 1N52W. CLUSTERS OF 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 3N TO S 
OF THE EQUATOR W OF 45W TO INLAND OVER SOUTH AMERICA. CLUSTERS 
OF SCATTERED MODERATE CONVECTION ARE WITHIN 120 NM OF THE AXIS 
FROM 18W-30W. 

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE REMAINS OVER THE GULF WITH THE AXIS EXTENDING 
FROM THE CARIBBEAN OVER W CUBA TO THE NORTH-CENTRAL GULF COAST. 
THIS CONTINUES TO ADVECT UPPER LEVEL MOISTURE ACROSS MEXICO AND 
THE W GULF. THE UPPER LEVEL LOW REMAINS OVER E NEW MEXICO/W 
TEXAS CLIPPING THE NW GULF ENHANCING THE SCATTERED SHOWERS/ 
ISOLATED THUNDERSTORMS OVER THE NW GULF N OF 22N W OF 92W. A 
SURFACE RIDGE COVERS THE E US INTO THE GULF ANCHORED BY A 1026 
MB HIGH IN THE W ATLC. LIGHT TO MODERATE EASTERLY SURFACE WINDS 
WITH SOME HIGHER GUSTS IN THE VICINITY OF THE SHOWER ACTIVITY 
CONTINUE TO DOMINATE THE GULF. OTHERWISE THE REMAINDER OF THE 
GULF REMAINS CLOUD AND SHOWER FREE. 
 
CARIBBEAN...
BROAD UPPER RIDGE COVERS THE ENTIRE CARIBBEAN EXTENDING FROM 
VENEZUELA ACROSS W CUBA INTO THE GULF OF MEXICO. MODERATE/STRONG 
SUBSIDENCE AND VERY DRY AIR AT ALL LEVELS CONTINUE TO LEAVE THE 
CARIBBEAN MOSTLY CLOUD FREE WITH VIRTUALLY NO SHOWERS. PRESSURE 
GRADIENT BETWEEN THE RIDGE OVER THE ATLC AND THE LOWER PRESSURES 
IN THE TROPICS ARE GENERATING MODERATE/STRONG EASTERLY TRADE 
WINDS BRINGING SOME LOW LEVEL MOISTURE WITH ISOLATED SHOWERS TO 
THE FAR E CARIBBEAN BETWEEN 62W-67W INCLUDING THE N LEEWARD/ 
VIRGIN ISLANDS. 

ATLANTIC...
BROAD DEEP LAYERED TROUGH COVERS THE W AND CENTRAL ATLC N OF 24N 
FROM 48W-80W WITH THE ASSOCIATED COLD FRONT EXTENDING INTO THE 
AREA THROUGH 32N51W TO A RECENT DEVELOPED 1016 MB LOW NEAR 
26N57W AND A SURFACE TROUGH CONTINUING S TO TO THE 
LEEWARD/VIRGIN ISLANDS NEAR 18N64W. SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS ARE WITHIN 180 NM E OF THE COLD FRONT WITH 
ISOLATED SHOWERS WITHIN 90/120 NM EITHER SIDE OF THE SURFACE 
TROUGH. THE SURFACE RIDGE OVER THE E US AND GULF OF MEXICO IS 
BUILDING E OVER THE W ATLC WITH A 1026 MB HIGH LOCATED BETWEEN 
BERMUDA AND THE NORTH CAROLINA COAST. THIS COMBINED WITH 
MODERATE SUBSIDENCE AND DRY AIR AT ALL LEVELS ARE LEAVING THE 
REMAINDER OF THE W ATLC MOSTLY CLOUD AND SHOWER FREE. AN UPPER 
LEVEL TROUGH OVER THE E ATLC EXTENDS INTO THE REGION N OF 20N E 
OF 30W TO THE COAST OF AFRICA WITH THE UPPER LOW MOVING ACROSS 
MADEIRA ISLANDS TOWARD THE CANARY ISLANDS. THE ASSOCIATED 
SURFACE 1010 MB LOW IS OVER THE MADEIRA ISLANDS WITH A SURFACE 
TROUGH EXTENDING S OVER THE CANARY ISLANDS TO NEAR 25N18W. A 
SURFACE RIDGE COVERS THE REMAINDER OF THE E AND CENTRAL ATLC N 
OF 15N BETWEEN 20W-50W ANCHORED BY A 1037 MB HIGH N OF THE 
AZORES. THE REMAINDER OF THE ATLC IS UNDER RATHER BENIGN UPPER 
LEVEL FEATURES AS WELL AS MODERATE/STRONG SUBSIDENCE AND VERY 
DRY AIR AT ALL LEVELS KEEPING THE REMAINDER OF THE ATLC QUIET 
AGAIN THIS MORNING. 

$$
WALLACE