000
AXNT20 KNHC 301728
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN DEC 30 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...
SURFACE LOW PRES...1008 MB..IS CENTERED OVER THE EASTERN ATLC 
ABOUT 900 MILES SSW OF THE AZORES. SATELLITE IMAGERY INDICATES 
THAT THIS SYSTEM IS NOW INTERACTING WITH A COLD  FRONT TO ITS N 
AND SHOWER AND TSTM ACTIVITY HAS BECOME LESS ORGANIZED 
THAN YESTERDAY.  HOWEVER...THIS SYSTEM CONTINUES TO PRODUCE 
GALE-FORCE WINDS...MAINLY TO THE N AND SLIGHTLY TO THE S OF THE 
CENTER...AND IT STILL COULD BECOME A SUBTROPICAL STORM LATER 
TODAY OR TOMORROW AS IT MOVES SLOWLY DURING THE NEXT COUPLE OF 
DAYS. MOST OF THE CONVECTION IS TO THE N OF THE LOW CENTER
FROM 29N-32N BETWEEN 31W-36W...WITH A LINE OF SHOWERS AND
POSSIBLE ISOLATED TSTMS FROM 28N34W 28N34W.

...THE ITCZ...
FROM 6N11W TO 2N30W TO 1N50W. SCATTERED SHOWERS ARE WITHIN 240 
NM N OF THE AXIS W OF 25W.

...DISCUSSION...
GULF OF MEXICO...
MID/UPPER LEVEL TROUGH IS DIGGING ACROSS TEXAS AND INTO THE FAR 
NW GULF OF MEXICO. THE GULF OF MEXICO E OF 87W IS COVERED BY 
ANTICYCLONIC FLOW FROM A RIDGE EXTENDING N FROM THE CARIBBEAN.
STATIONARY FRONT EXTENDS FROM NEAR PENSACOLA FLORIDA ACROSS THE 
MOUTH OF THE MISSISSIPPI TO 25N95W. SCATTERED SHOWERS AND TSTMS
ARE ALONG THE FRONT N OF 28N WITH...OVERCAST CLOUDS W OF THE
FRONT.

CARIBBEAN SEA
UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED BETWEEN JAMAICA
AND HAITI. MODERATE TO STRONG SUBSIDENCE...WITH DRY AIR AT THE 
MIDDLE AND UPPER LEVELS OF THE ATMOSPHERE...COVERS NEARLY ALL
OF THE CARIBBEAN. HOWEVER..SCATTERED SHOWERS ARE LIKELY IN THE 
FAST MOVING SCATTERED TO BROKEN LOW CLOUDS E OF 75W AND ALSO
ACROSS THE NW CARIBBEAN W OF 85W.

ATLANTIC
MID/UPPER LEVEL RIDGE ACROSS THE WESTERN ATLC EXTENDS FROM AN
ANTICYCLONIC CIRCULATION IN THE CARIBBEAN ACROSS THE SOUTHERN
BAHAMAS TO 32N70W. MODERATE TO STRONG SUBSIDENCE COVERS MOST
OF THE ATLC S OF 30N W OF 60W. DOWNSTREAM TROUGH WITH AXIS FROM
32N40W TO NEAR WITH WINDWARD ISLANDS 14N59W. AN UPPER LEVEL
ANTICYCLONIC CIRCULATION IS E OF THE TROUGH CENTERED NEAR 
28N27N WITH RIDGE EXTENDING NWD TO 32N25W. UPPER LEVEL
DIFFLUENT FLOW BETWEEN THE TROUGH AND THE RIDGE IS ENHANCING
CONVECTIVE ACTIVITY ON THE N SIDE OF LOW PRES DESCRIBED
IN SPECIAL FEATURES. A 90-100 KT SUBTROPICAL JETSTREAM 
EXTENDS FROM 11N51W TO 20N35W THEN TO AFRICA NEAR 25N15W.
BROKEN/OVERCAST MIDDLE AND HIGH CLOUDS ARE WITHIN 400 NM
S OF THE JET AXIS. TRANSVERSE BANDING IS NOTED ON THE
HIGH CLOUDS E OF 35W INDICATING POSSIBLE HIGH LEVEL
TURBULENCE. MODERATE/STRONG SUBSIDENCE IS N OF THE JET
W OF 40W.

$$
DGS