000
AXNT20 KNHC 121121
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST TUE DEC 12 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 8N10W 5N25W 3N42W 2N52W. CLUSTERS OF 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 1N-7N 
BETWEEN 13W-30W.

...DISCUSSION...
GULF OF MEXICO...
BROAD MID/UPPER LEVEL TROUGH IS MOVING ACROSS THE CENTRAL US 
INTO THE MISSISSIPPI VALLEY AND THE NW GULF N OF 24N W OF 90W. 
LOW/MID LEVEL TROUGH REMAINS OVER THE S/CENTRAL GULF WITH A WEAK 
SURFACE TROUGH EXTENDING FROM S MEXICO ACROSS THE BAY OF 
CAMPECHE ALONG 20N93W N TO OFF THE TEXAS COAST NEAR 28N95W. THE 
REMAINDER OF THE GULF IS DOMINATED BY AN UPPER RIDGE WITH THE 
AXIS EXTENDING FROM THE CARIBBEAN ALONG 80W COVERING THE W ATLC 
DRAWING TROPICAL MOISTURE N ACROSS THE SE GULF TO 26N E OF 86W 
BRINGING SCATTERED SHOWERS AND WIDELY ISOLATED THUNDERSTORMS 
OVER THAT AREA. ALSO AT THE SURFACE...RIDGE THAT DOMINATES THE W 
ATLC AND THE E US IS BEGINNING TO SHIFT E WITH THE APPROACHING 
DEEP LAYERED TROUGH MOVING OVER THE MISSISSIPPI VALLEY. 

CARIBBEAN SEA...
BROAD MID/UPPER LEVEL RIDGE DOMINATES THE CARIBBEAN ANCHORED BY 
AN UPPER HIGH OVER NW VENEZUELA EXTENDING N INTO THE W ATLC 
ALONG 80W. THIS IS DRAWING TROPICAL MOISTURE N OVER THE NW 
CARIBBEAN GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N 
OF 17N FROM 80W-86W. THIS UPPER LEVEL FLOW COMBINED WITH 
MODERATE/STRONG EASTERLY TRADE WINDS ACROSS THE CARIBBEAN ARE 
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 11N W 
OF 80W. ALTHOUGH THE REMAINDER OF THE CARIBBEAN IS UNDER DRY 
UPPER AIR AND MODERATE/STRONG SUBSIDENCE...LOW LEVEL MOISTURE IS 
EVIDENT WITH ISOLATED SHOWERS FROM 12N-17N BETWEEN 66W-79W. 

ATLANTIC OCEAN...
BROAD MID/UPPER LEVEL RIDGE FROM THE CARIBBEAN COVER THE FAR W 
ATLC W OF 65W INTO THE E GULF OF MEXICO. DEEP LAYERED TROUGH 
COVERS THE W/CENTRAL ATLC N OF 23N BETWEEN 45W-65W. THE 
ASSOCIATED COLD FRONT ENTERS THE REGION NEAR 32N49W EXTENDING SW 
TO 24N58W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 26N 
FROM 41W-48W. A NARROW UPPER RIDGE EXTENDS FROM THE W TROPICAL 
ATLC NEAR 18N48W NNE TO BEYOND 32N40W. A CUT-OFF UPPER LOW IS 
IN THE E ATLC NEAR 23N31W COVERING THE AREA FROM 15N-29N BETWEEN 
20W-37W WITH AN UPPER RIDGE OVER THE SE ATLC ALONG THE COAST OF 
AFRICA. A WEAK SURFACE TROUGH EXTENDS FROM 20N45W TO 12N48W BUT 
IS EMBEDDED WITHIN DRY UPPER AIR AND STRONG SUBSIDENCE. BROAD 
SURFACE RIDGE DOMINATES THE E ATLC. 

$$
WALLACE