AXNT20 KNHC 021748
TWDAT 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE DEC 02 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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 1715 UTC.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 8N12W 7N19W 8N38W 5N54W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-9N 
BETWEEN 12W-19W. SCATTERED MODERATE CONVECTION IS FROM 4N-10N 
BETWEEN 29W-39W AND FROM 5N-10N BETWEEN 43W-50W.

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYERED TROUGH IS ACROSS THE SE CONUS AND THE FLORIDA 
PANHANDLE TOWARD THE SW GULF OF MEXICO AND IS SUPPORTING A COLD 
FRONT THAT PASSES THROUGH A FORT PIERCE TO NAPLES FLORIDA LINE 
AND SW TO NEAR 24N85W TO 23N90W. MIDDLE TO UPPER LEVEL DRY AIR 
AND STRONG SUBSIDENCE IS OVER THE ENTIRE GULF REGION. BROKEN TO 
OVERCAST MIDDLE AND HIGH CLOUDS ARE OBSERVED IN THE SE GULF AND 
STRAITS OF FLORIDA WITH POSSIBLE ISOLATED SHOWERS WITHIN 90 NM 
OF THE FRONTAL BOUNDARY. BEHIND THE FRONT SCATTERED COLD AIR 
STRATOCUMULUS CLOUDS ARE EVIDENT ON SATELLITE IMAGERY N OF 24N 
AND E OF 89W. NEXT COLD FRONTAL BOUNDARY IS FORECAST TO ENTER 
THE NW GULF ON THURSDAY MORNING.

CARIBBEAN SEA...
A COLD FRONT ENTERS THE WRN CARIBBEAN FROM ACROSS ERN CUBA TO 
NEAR 18N80W AND INTO A 1015 MB SURFACE LOW PRESSURE NEAR 15N83W. 
SCATTERED SHOWERS AND TSTMS ARE WITHIN 150 NM ON EITHER SIDE OF 
THE FRONT WITH SCATTERED MODERATE CONVECTION ACROSS THE SW 
CARIBBEAN S OF 15N AND W OF 76W. THIS FRONT IS BEGINNING TO 
STALL AND IS FORECAST TO TURN STATIONARY OVER THE NEXT 12-24 
HOURS ACROSS THE WRN CARIBBEAN. A SURFACE TROUGH IS LOCATED IN 
THE ERN CARIBBEAN ALONG 68W SOUTH OF 16N. SCATTERED SHOWERS ARE 
FROM 12N-17N BETWEEN 65W-71W. BROKEN LOW TO MIDDLE LEVEL CLOUDS 
ARE ACROSS THE LEEWARD ISLANDS AND PUERTO RICO USHERED IN ON 
E-NE 15-20 KT TRADES. IN THE UPPER LEVELS...A SHARP AMPLIFIED 
RIDGE IS LOCATED IN THE W ATLC AND EXTENDS A RIDGE AXIS INTO THE 
CENTRAL CARIBBEAN THROUGH THE MONA PASSAGE TO NEAR 12N76W.

ATLANTIC OCEAN...
A COLD FRONT IS SUPPORTED BY THE AFOREMENTIONED UPPER LEVEL 
TROUGHING ACROSS THE ERN GULF OF MEXICO AND EXTENDS SW FROM A 
1017 MB LOW THAT IS CENTERED IN THE W ATLC NEAR 32N76W TO NEAR 
FORT PIERCE FLORIDA. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE 
FRONT N OF 26N. ANOTHER COLD FRONT ENTERS THE W ATLC NEAR 32N69W 
AND EXTENDS SW OVER CAT ISLAND AND THE EXUMA CAYS IN THE BAHAMAS 
TO OVER ERN CUBA AND INTO THE WRN CARIBBEAN. UPPER LEVEL SWLY 
WIND FLOW FROM A LARGE-SCALE RIDGE CENTERED NEAR 26N62W IS 
CREATING A LARGE AREA OF UPPER DIFFLUENCE INDUCING SCATTERED 
SHOWERS AND ISOLATED TSTMS FROM 20N TO BEYOND 32N BETWEEN 
69W-80W ACROSS MUCH OF THE BAHAMAS AND ERN CUBA. THE UPPER LEVEL 
RIDGE AXIS LIES ALONG A LINE FROM THE MONA PASSAGE TO BEYOND 
32N59W. A SURFACE RIDGE IS ALONG A LINE FROM 23N68W TO BEYOND 
32N56W. A LARGE-SCALE DEEP LAYER TROUGH COVERS THE CENTRAL ATLC 
WITH AN UPPER LOW CENTERED NEAR 29N38W. BROAD CYCLONIC SURFACE 
FLOW IS OBSERVED BETWEEN 25W-47W WITH ONE 1013 MB SURFACE LOW 
NEAR 29N40W AND ANOTHER 1012 MB SURFACE LOW N OF THE AREA NEAR 
34N33W. A SURFACE TROUGH CURVES FROM THIS LOW TO 32N31W TO 
27N30W AND SW TO NEAR 11N47W. SCATTERED SHOWERS AND POSSIBLE 
ISOLATED TSTMS ARE WITHIN 250 NM ON EITHER SIDE OF THE 
TROUGH...UNDER AN UPPER LEVEL SOUTHWESTERLY WIND FLOW REGIME 
LOCATED ON THE ERN SIDE OF A TROUGH AND ON THE WRN SIDE OF A 
RIDGE. THIS RIDGE IS CENTERED OVER SIERRA LEONE AND IS PROVIDING 
AN UPPER LEVEL DIFFLUENT PATTERN SUPPORTING THE CONVECTION ALONG 
THE ITCZ AXIS.

$$
HUFFMAN