000
AXNT20 KNHC 271115
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST TUE DEC 27 2011

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL 
ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1100 UTC.

...ITCZ/MONSOON TROUGH...

A GREAT PORTION OF THE MONSOON TROUGH REMAINS INLAND OVER 
AFRICA. A SMALL SECTION OF IT ENTERS THE ATLC THROUGH THE COAST 
OF LIBERIA ALONG 6N10W AND QUICKLY ENDS AT 4N17W. THE ITCZ AXIS 
EXTENDS WSW FROM THIS POINT ALONG 4N30W 3N40W TO THE COAST OF 
BRAZIL NEAR 2N50W. SCATTERED WEAK TO MODERATE CONVECTION IS 
WITHIN 70-100 NM ON EITHER SIDE OF THE ITCZ/MONSOON TROUGH AXIS.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL SHORTWAVE MOVING 
ACROSS THE NW AND N CENTRAL GULF BASIN. THIS FEATURE SUPPORTS AN 
OCCLUDED 1007 MB LOW CENTERED OVER WRN TENNESSEE WITH A COLD 
FRONT ENTERING THE GULF ALONG 30N85W EXTENDING SW TO 24N90W THE 
SOUTH TO THE SOUTHERN MEXICO COAST NEAR 18N93W. MOSAIC DOPPLER 
RADAR IMAGERY INDICATES A FAST MOVING PRE-FRONTAL LINE OF HEAVY 
SHOWERS AND THUNDERSTORMS MOVING ACROSS THE FAR NE GULF BASIN N 
OF 26N. SCATTERED SHOWERS ARE OCCURRING WITHIN 50 NM EITHER SIDE 
OF THE FRONT. A BROAD AREA OF OVERCAST LOW LEVEL STRATOCUMULUS 
CLOUDS EXTENDS 120 NM W OF THE FRONT. WEST OF THE FRONT...GUSTY 
NW WINDS IN THE RANGE OF 15 TO 25 KT ARE FORECAST TO CONTINUE 
THROUGH THE MORNING HOURS AS HIGH PRESSURE ANCHORED OVER 
NORTHERN MEXICO AND TEXAS BUILDS IN ACROSS THE WESTERN AND 
CENTRAL GULF THROUGH LATE TUESDAY INTO WEDNESDAY.

CARIBBEAN SEA...
VERY DRY AIR ALOFT AND STRONG SUBSIDENCE COVERS MOST OF THE 
CARIBBEAN WATERS THIS MORNING. THIS AIRMASS IS SUPPRESSING DEEP 
CONVECTION ACROSS THE DISCUSSION AREA. FRESH TO STRONG TRADE 
WIND FLOW CONTINUES ACROSS MUCH OF THE BASIN...ESPECIALLY 
BETWEEN 68W-80W AND NEAR THE COAST OF COLOMBIA...WITH A FEW 
SMALL CLUSTERS OF LOW-TOP WEAK SHOWERS EMBEDDED IN THE FLOW 
INCLUDING COASTAL PORTIONS OF NORTHERN NICARAGUA...HONDURAS... 
AND BELIZE. THESE CONDITIONS ARE EXPECTED TO PERSIST THROUGH 
WEDNESDAY MORNING.

ATLANTIC OCEAN...
AN UPPER LEVEL SHORTWAVE/TROUGH MOVES ACROSS THE NW ATLC NORTH 
OF THE DISCUSSION AREA SUPPORTING A COLD FRONT ANALYZED INTO THE 
AREA ALONG 32N53W CONTINUING WSW ALONG 27N62W TO 26N71W...WHERE 
LOW-LEVEL MOISTURE BECOMES MORE DIFFUSE AND A WEAK STATIONARY 
FRONT CONTINUES WESTWARD INTO THE NW BAHAMAS ALONG 27N78W. 
POSSIBLE ISOLATED SHOWERS ARE OCCURRING WITHIN 70 NM EITHER SIDE 
OF THE FRONT. AN EARLIER ASCAT PASS DEPICTED STRONGER NORTHERLY 
WINDS UP TO 30 KT NORTH OF THE FRONT EAST OF 70W. GALE FORCE 
WINDS ARE N OF 30N WITHIN 240 NM E OF FRONT GENERATING SEAS 8 TO 
12 FT. IN THE MEAN TIME...AN UPPER LEVEL RIDGE IS BUILDING 
ACROSS THE WESTERN ATLC WITH DRY AIR ALOFT AND STRONG SUBSIDENCE 
NOTICED ON WATER VAPOR IMAGERY. THIS FEATURE SUPPORTS A 1024 MB 
HIGH CENTERED NEAR 34N70W. A WEAK AREA OF LOW LEVEL CONFLUENCE 
OF LIGHT WINDS IS ANALYZED AS A WEAK SURFACE TROUGH FROM 20N47W 
TO 14N50W WITHOUT ANY RAINSHOWER ACTIVITY ASSOCIATED. THE 
REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF AN UPPER 
LEVEL LOW CENTERED NEAR 19N32W. A SIGNIFICANT AMOUNT OF MOISTURE 
AND POSSIBLE SCATTERED SHOWERS AND TSTMS SUPPORTED BY STRONG 
MIDDLE TO UPPER LEVEL DIFFLUENCE ARE LOCATED EAST OF THE UPPER 
LOW FROM 10N-20N E OF 28W. 

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$

GARCIA