000
AXNT20 KNHC 211124
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU DEC 21 2006

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 
1045 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N7W 3N12W 5N20W 5N47W 4N52W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM OF 
THE AXIS FROM 41W-50W. CLUSTERS OF SCATTERED MODERATE CONVECTION 
ARE WITHIN 75 NM OF THE AXIS FROM 13W-40W. 

...DISCUSSION...
GULF OF MEXICO...
DEEP LAYERED TROUGH IS MOVING INTO THE NW GULF W OF 88W WITH A 
LARGE UPPER LOW OVER THE CENTRAL PLAIN STATES. THE ASSOCIATED 
COLD FRONT EXTENDS FROM THE LOUISIANA/TEXAS BORDER JUST OFF THE 
TEXAS COAST TO A 12 MB LOW JUST S OF BROWNSVILLE TEXAS. 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE E OF THE FRONT AND 
W OF A LINE FROM THE FLORIDA PANHANDLE NEAR PENSACOLA ALONG 
27N92W TO THE TEXAS/MEXICO BORDER. UPPER RIDGE COVERS THE 
REMAINDER OF THE GULF WITH THE AXIS EXTENDING FROM THE W 
CARIBBEAN ACROSS CUBA AND S FLORIDA TO OFF THE SE US COAST. 
TROPICAL MOISTURE CONTINUES TO STREAM ACROSS MEXICO FROM THE E 
PACIFIC REGION TO OVER THE FAR W GULF. ISOLATED SHOWERS REMAIN 
OVER THE FAR SE GULF S OF 25N E OF 87W THROUGH THE STRAITS OF 
FLORIDA INCLUDING THE FLORIDA KEYS. 
 
CARIBBEAN SEA...
CUT-OFF UPPER LEVEL LOW IS OVER THE NW CARIBBEAN N OF 16N FROM 
74W-85W. THE REMAINDER OF THE CARIBBEAN IS DOMINATED BY AN UPPER 
RIDGE ANCHORED IN THE W TROPICAL ATLC. VERY DRY UPPER AIR AND 
MODERATE/STRONG SUBSIDENCE COVERS MOST OF THE AREA WITH THE 
EXCEPTION OF WIDELY ISOLATED LOW LEVEL SHOWERS N OF 15N BETWEEN 
76W-84W ENHANCED BY STRONG TRADE WINDS THAT ALSO DOMINATES THE 
CARIBBEAN AND A WEAK SURFACE TROUGH THAT EXTENDS FROM 16N77W 
THROUGH THE WINDWARD PASSAGE TO OVER THE TURKS AND CAICOS.  

ATLANTIC OCEAN...
UPPER RIDGE COVERS THE FAR W ATLC W OF 70W WITH THE AXIS FROM 
THE W CARIBBEAN ACROSS CUBA AND S FLORIDA TO OFF THE SE US COAST 
BEYOND 32N78W. DEEP LAYERED TROUGH IS OVER THE W ATLC N OF 20N 
FROM 48W-70W WITH THE ASSOCIATED COLD FRONT EXTENDING THROUGH 
32N49W WSW ALONG 27N62W TO 28N76W. A REMNANT SURFACE TROUGH IS 
IN THE CENTRAL ATLC EXTENDING FROM 30N50W TO 21N64W WITH 
ISOLATED SHOWERS WITHIN 180 NE E OF THE TROUGH N OF 25N. THE 
UPPER LOW IN THE NW CARIBBEAN IS GENERATING SCATTERED SHOWERS/ 
ISOLATED THUNDERSTORMS S OF 23N TO OVER HISPANIOLA AND CUBA 
BETWEEN 70W-80W WHILE THE REMAINDER OF THE W ATLC REMAINS RATHER 
SHOWER FREE. NARROWING UPPER RIDGE EXTENDS FROM THE TROPICS NEAR 
18N48W N ACROSS THE CENTRAL ATLC ALONG 25N45W TO BEYOND 32N40W 
WITH A WEAK 1024 MB HIGH LOCATED NEAR 28N38W. BROAD UPPER TROUGH 
COVERS THE REMAINDER OF THE ATLC WITH THE AXIS EXTENDING THROUGH 
32N13W SW TO 16N33W AND A 1016 MB SURFACE LOW NEAR 27N27W. 

$$
WALLACE