000
AXNT20 KNHC 132324
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED DEC 13 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...THE ITCZ...
ITCZ AXIS IS ALONG 6N12W 4N22W 4N40W 2N50W . SCATTERED 
MODERATE CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE AXIS 
BETWEEN 22W-33W. ISOLATED MODERATE IS WITHIN 90 NM S OF THE 
AXIS E OF 18W.

...DISCUSSION...
THE GULF OF MEXICO...
A FEW SCATTERED SHOWERS OVER THE SE GULF IN A LARGE AREA OF 
CLOUDINESS. SCATTERED CLOUDS WITH AREAS OF RAIN AND A FEW 
POSSIBLE SHOWERS ARE OVER THE SW GULF . A FEW PATCHES OF LOW 
CLOUDS AND LIGHT SHOWERS ARE ELSEWHERE.
  
THE CARIBBEAN SEA...
A TROUGH ALONG THE SW PORTION IS CAUSING SCATTERED SHOWERS AND 
ISOLATED THUNDERSTORMS S OF 16N W OF 80W. ANOTHER TROUGH NEAR 
THE YUCATAN COAST IS CAUSING SCATTERED SHOWERS. THIS TROUGH HAS 
BECOME A LITTLE BETTER DEFINED WITH LOW-LEVEL CYCLONIC TURNING 
IN THE WINDS EVIDENT IN SATELLITE IMAGERY AND AN EARLIER QSCAT 
PASS. SOME LIFT NEAR THE SFC TROUGH ALONG WITH WEAK UPPER 
DIFFLUENCE...BETWEEN A BROAD FLAT RIDGE CENTERED OVER COLOMBIA 
AND STRONGER UPPER LEVEL WLY FLOW IN THE NW CARIB...IS SPARKING 
SCATTERED SHOWERS AND ISOLATED TSTMS FROM 11N-17N BETWEEN 
78W-84W. DEEPER MORE CONVECTIVE ACTIVITY...ASSOCIATED WITH THE 
ITCZ...LIES FURTHER S OVER COLOMBIA AND THE EXTREME SW CARIB. 
THE REMAINDER OF THE AREA IS QUIET UNDER MODERATELY DRY AIR 
ALOFT ASSOCIATED WITH THE BROAD UPPER LEVEL RIDGE. TRADE WINDS 
ARE MOSTLY IN THE 15-20 KT RANGE EXCEPT FOR SOME STRONGER WINDS 
IN THE S CENTRAL CARIB DUE TO LOWER PRES OVER N SOUTH AMERICA. 
NO MAJOR CHANGES IN THESE WINDS ARE EXPECTED THRU THE WEEK.
 
THE ATLANTIC OCEAN...
A LONGWAVE RIDGE/TROUGH/RIDGE PATTERN IS ESTABLISHED ACROSS THE 
DISCUSSION AREA. VERTICALLY STACKED RIDGING EXISTS IN THE WRN 
ATLC WITH THE MEAN AXIS ALONG 68W. A BAND OF STRONG MID-UPPER 
LEVEL WINDS OR A WEAK JET STRETCHES FROM THE BAHAMAS EASTWARD TO 
22N45W THEN RACING NWD IN RESPONSE TO THE TROUGH IN THE CENTRAL 
ATLC. N OF THE WEAK JET...PLENTY OF DRY STABLE AIR ALOFT EXISTS 
W OF 40W. THIS STRONG MID-LEVEL CAP IS KEEPING THE PATCHES OF 
LOW-LEVEL MOISTURE DRIVEN BY FRESH NE-E WINDS SHALLOW. A BROAD 
TROUGH DOMINATES THE CENTRAL ATLC WITH THE UPPER AXIS ALONG 43W. 
 A PLUME OF MOISTURE ASSOCIATED WITH THE SFC FRONT AND UPPER 
LEVEL JET MENTIONED IS N OF 23N BETWEEN 36W-43W.  THE 
SUBTROPICAL E ATLC IS DOMINATED BY STRONG VERTICALLY STACKED 
RIDGING WITH THE UPPER HIGH CENTER NEAR 31N24W AND THE 1028 MB 
SFC CENTER FURTHER TO THE NE. A WEAKENING CUT OFF UPPER LEVEL 
LOW IS EMBEDDED IN THE LARGE SCALE RIDGE NEAR 25N29W. THIS UPPER 
LEVEL FEATURE IS ONLY PRODUCING SOME ISOLATED SHOWERS IN ITS 
VICINITY. THE UPPER LOW APPEARS THAT IT WILL BE COMPLETELY 
OVERTAKEN SHORTLY BY A NARROW RIDGE TO ITS W AS SUGGESTED BY 
GFS.   

$$
TORRES