000
AXNT20 KNHC 011744
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT DEC 01 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 
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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1730

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 6.5W10W 5N25W 5N35W 2.5N51W. 
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE 
WITHIN 90 NM EITHER SIDE OF THE ITCZ AXIS E OF 20W TO THE COAST 
OF W AFRICA AND WITHIN 60 NM OF LINE FROM 5N30W TO 8N37.5W.  

DISCUSSION...

GULF OF MEXICO...
A SURFACE RIDGE DOMINATES THE E HALF OF THE US EXTENDING S OVER 
THE ENTIRE GULF OF MEXICO. AN UPPER RIDGE EXTENDS OVER MEXICO 
EAST OF 110W AND THE U.S. EAST OF ABOUT 100W AND COVERS MOST OF 
THE GULF. A UPPER SHORTWAVE TROUGH EXTENDS FROM THE W ATLC 
ACROSS THE STRAITS OF FLORIDA TO THE NE YUCATAN PENINSULA. 
MOSTLY DRY STABLE AIR DOMINATES THE GULF. HOWEVER...SOME 
SCATTERED SHOWERS DOT THE SE GULF S OF 24N W OF 88W. 

CARIBBEAN SEA...
A BROAD UPPER RIDGE COVERS THE W CARIBBEAN WITH THE AXIS 
EXTENDING FROM COLOMBIA TO THE S COAST OF CUBA COVERING THE AREA 
W OF 70W. THE SOUTHERN EXTENSION OD A BROAD UPPER LOW IN THE 
SOUTH CENTRAL ATLC COVERS THE E CARIBBEAN E OF 70W WITH DRY 
STABLE AIR DOMINATING THE ENTIRE REGION. MODERATE/STRONG NE 
TRADE WINDS DOMINATE THE CARIBBEAN USHERING IN SOME ISOLATED 
FAST MOVING SHOWERS S OF 13.5N FROM 68W-78W. 

ATLANTIC OCEAN...
A UPPER SHORTWAVE TROUGH EXTENDS THROUGH 32N64W TO THE STRAITS 
OF FLORIDA AND OVER THE SE GULF OF MEXICO.  SCATTERED SHOWERS 
ARE WITHIN 90 NM OF THE SURFACE TROUGH. THE UPPER RIDGE EXTENDS 
ACROSS THE W ATLC FROM CENTRAL CUBA TO 27N64W AND IS WEAKENING 
OVER THE ATLANTIC PART. BROAD UPPER LOW IS CENTERED IN THE SOUTH 
CENTRAL ATLC NEAR 24N55W COVERING THE AREA FROM 48W-68W 
INCLUDING THE E CARIBBEAN. A SURFACE TROUGH EXTENDS FROM 30N54W 
TO 19N59W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 
22N-29N BETWEEN 52W-58W. SMALL WEAK UPPER LOW IS IN THE E ATLC 
NEAR 29N35W WITH AN UPPER TROUGH OVER THE FAR E ATLC N OF 20N E 
OF 24W AND NO SURFACE REFLECTIONS ASSOCIATED WITH EITHER OF 
THESE UPPER LEVEL FEATURES. UPPER RIDGE COVERS MUCH OF THE 
TROPICS S OF 20N E OF 50W TO INLAND OVER AFRICA PROVIDING UPPER 
LEVEL DIFFLUENCE TO GENERATE SCATTERED SHOWERS AND POSSIBLE 
ISOLATED THUNDERSTORMS WITHIN 200 NM OF LINE FROM 7N54W TO 
20N48W. A JET STREAM WITH WINDS ESTIMATED TO BE 80 TO 110 KT 
EXTENDS AROUND THE N BOUNDARY OF THIS UPPER RIDGE WITH THE 
STRONGEST WINDS E OF 25W. AT THE SURFACE...A BROAD SURFACE RIDGE 
COVERS THE ATLC WITH A WEAKNESS ALONG THE SURFACE TROUGH.    

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