000
AXNT20 KNHC 291154
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU DEC 29 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...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST OF GUINEA NEAR 
10N14W TO 5N22W. THE ITCZ AXIS EXTENDS WSW FROM THIS POINT ALONG 
3N33W TO THE COAST OF BRAZIL NEAR 1S47W. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION IS WITHIN 120 NM ON THE NRN SIDE OF 
THE ITCZ AXIS BETWEEN 20W-30W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL SHORTWAVE PROGRESSING 
OVER THE N CENTRAL GULF BASIN ADVECTING MIDDLE TO UPPER LEVEL 
MOISTURE ACROSS THE NE CORNER OF THE BASIN. DESPITE THE UPPER 
LEVEL FEATURE...A 1022 MB HIGH IS CENTERED OVER THE FLORIDA 
PANHANDLE NEAR 30N82W. THIS FEATURE IS PROMOTING LIGHT AND 
VARIABLE WINDS AND FAIR WEATHER CONDITIONS ACROSS THE AREA. THE 
HIGH IS FORECAST TO SLIDE EASTWARD THROUGH SATURDAY AND MOVE 
INTO THE SW NORTH ATLC BY SUNDAY. THE NEXT COLD FRONT IS THEN 
EXPECTED BY SUNDAY MORNING TO ENTER THE NW GULF USHERING IN 
STRONG NORTHERLY WINDS THAT WILL SPREAD EASTWARD ACROSS THE GULF 
THROUGH EARLY NEXT WEEK.

CARIBBEAN SEA...
VERY DRY AIR ALOFT AND STRONG SUBSIDENCE COVERS THE CARIBBEAN 
WATERS THIS MORNING. THIS AIRMASS IS SUPPRESSING DEEP CONVECTION 
ACROSS THE DISCUSSION AREA. MODERATE TO FRESH TRADE WIND FLOW 
CONTINUES ACROSS MUCH OF THE CENTRAL AND ERN BASIN...ESPECIALLY 
BETWEEN 67W-77W AND STRONGER WINDS NEAR THE COAST OF COLOMBIA. A 
FEW SMALL CLUSTERS OF LOW-TOP WEAK SHOWERS ARE EMBEDDED IN THE 
FLOW. THESE CONDITIONS ARE EXPECTED TO PERSIST THROUGH FRIDAY AS 
A RIDGE WILL POSITION ITSELF IN THE SW NORTH ATLC AND INCREASE 
THE TRADES DUE TO AN INCREASED PRESSURE GRADIENT. THE TRADES 
WILL REMAIN STRONG BASIN-WIDE THROUGH THE UPCOMING WEEKEND.

ATLANTIC OCEAN...
A BROAD UPPER LEVEL TROUGH IS MOVING ACROSS THE NW ATLC 
SUPPORTING A COLD FRONT ANALYZED INTO THE DISCUSSION AREA ALONG 
32N60W BECOMING A WEAK STATIONARY FRONT ACROSS THE CENTRAL 
BAHAMAS NEAR 25N74W TO THE COAST OF CUBA NEAR 22N78W. SCATTERED 
WEAK SHOWERS AND POSSIBLE ISOLATED TSTMS ARE OCCURRING WITHIN 
30-50 NM ON EITHER SIDE OF THE FRONT. HIGH PRESSURE WILL 
CONTINUE TO BUILD IN BEHIND THE FRONT FROM THE FAR EASTERN GULF 
OF MEXICO ACROSS THE REMAINDER OF THE SW NORTH ATLC THROUGH 
EARLY FRIDAY. FARTHER EAST...A NARROW UPPER LEVEL TROUGH IS 
MOVING ACROSS THE N CENTRAL ATLC OUTSIDE THE DISCUSSION AREA. 
THIS UPPER LEVEL FEATURE SUPPORTS THE TAIL END OF A COLD FRONT 
THAT EXTENDS INTO THE AREA ALONG 32N38W TO 25N42W. LOW-LEVEL 
MOISTURE REMAINS LIMITED WITH THIS FRONT...WITH JUST A FEW WEAK 
ISOLATED SHOWERS WITHIN 30 NM ON EITHER SIDE OF THE FRONT. THE 
REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A STRONG 
SURFACE RIDGE ANCHORED N OF THE DISCUSSION AREA.

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

$$

GARCIA