000
AXNT20 KNHC 311739
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST MON DEC 31 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 1715 UTC

...SPECIAL FEATURE...
A 1006 MB LOW PRES LOCATED NEAR 26N36W OR ABOUT 1000 NM S-SW OF 
THE AZORES. THE LOW IS PRODUCING A LARGE AREA OF GALE FORCE 
WINDS OVER THE N SEMICIRCLE...DUE TO A STRONG PRES GRADIENT 
BETWEEN THE LOW AND HIGHER PRES TO THE NW. HOWEVER THE 
CONVECTIVE ACTIVITY HAS BECOME DISORGANIZED AND HAS MOVED FAR 
FROM THE LOW CENTER...ABOUT 100 NM SW OF THE CENTER...SOME 
SCATTERED SHOWERS REMAIN NEAR THE LOW CENTER. THIS LOW IS NO 
LONGER EXPECTED TO BECOME A TROPICAL OR SUBTROPICAL SYSTEM.
  
...THE ITCZ...
THE ITCZ EXTENDS FROM THE LIBERIA COAST NEAR 6N10W TO 3N15W 
3N40W EQ46W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM
S OF AXIS FROM 11W-23W.

...DISCUSSION...
GULF OF MEXICO...
A COLD FRONT EXTENDS FROM CEDAR KEY FLORIDA TO 28N84W THE 
BECOMES STATIONARY AT 26N89W THEN DISSIPATING TO 20N95W. BROKEN 
TO OVERCAST LOW CLOUDS ARE WITHIN 140 NM N OF THE FRONT E OF 
89W...AND SCATTERED TO BROKEN WITHIN 120 NM N OF FRONT W OF 89W. 
SCATTERED SHOWERS SE OF THE FRONT FROM 25N-27N E OF 84W...ARE 
ABOUT TO MOVE INTO THE FORT MYERS FLORIDA AREA. BROAD UPPER 
LEVEL TROUGH COVERS THE GULF W OF 90W...WITH MODERATE TO STRONG 
SUBSIDENCE W OF 90W AND N OF 27N E OF 90W. THIS DRY AIR IS 
BRINGING MOSTLY CLEAR SKIES TO THE AREA...EXCEPT FOR THE AREA 
NEAR THE FRONT.

CARIBBEAN SEA...
TRANQUIL CONDITIONS PREVAIL ACROSS THE CARIBBEAN BENEATH AN 
AMPLIFIED MID TO UPPER RIDGE WITH AXIS FROM THE COAST OF 
COLOMBIA TO THE WINDWARD PASSAGE. MODERATE TO STRONG SUBSIDENCE 
WITH WIDESPREAD DRY AIR ALOFT IS EVIDENT ON WATER VAPOR
IMAGERY ESPECIALLY E OF THE HIGH WHERE THE FLOW ALOFT IS 
CONFLUENT DUE TO THE PRESENCE OF AN ELONGATED TROUGH E OF THE 
AREA. THIS STABLE AIRMASS IS SUPPRESSING THE DEVELOPMENT OF 
ORGANIZED DEEP CLOUDINESS. PATCHY MID-HIGH LEVEL CLOUDS ARE 
STREAMING NWD ON THE W SIDE OF THE HIGH W OF 80W. A FEW
SHOWERS ARE LIKELY IN THE FAST MOVING LOW CLOUDS ACROSS
MUCH OF THE BASIN.

ATLANTIC OCEAN...
MID AND UPPER LEVEL AMPLIFIED RIDGE CENTERED IN THE CARIBBEAN 
COVERS THE AREA W OF 55W. EXCEPT FOR THE AREA N OF THE BAHAMAS
STRONG SUBSIDENCE WITH DRY AIR AT THE MID TO UPPER LEVELS OF
THE ATMOSPHERE COVERS THE AREA W OF 50W. SHARP MID/UPPER LEVEL
TROUGH EXTENDS FROM 30N26W TO A WELL DEFINED CYCLONIC 
CIRCULATION NEAR 26N34W THEN CONTINUES S TO THE WINDWARD
ISLANDS. A 95-105 KT SUBTROPICAL JET S OF THE TROUGH FROM 
15N47W 26N25W TO THE COAST OF AFRICA NEAR 25N15W. UPPER 
DIFFLUENCE TO THE RIGHT OF THE JET AXIS IS GENERATING AND 
ADVECTING DENSE MID-HIGH LEVEL CLOUDS AND EMBEDDED SHOWERS 
WITHIN 600 NM S OF THE AXIS.  

$$
DGS