000
AXNT20 KNHC 270530
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0515 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 5N13W. THE ITCZ AXIS 
EXTENDS WSW FROM THIS POINT ALONG 5N20W 3N30W 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 A 
1014 MB LOW CENTERED OVER SRN MISSISSIPPI WITH A COLD FRONT 
EXTENDING SOUTHWARD FROM THE LOW TO 25N92W WHERE IT BECOMES 
STATIONARY TO THE SOUTHERN MEXICO COAST NEAR 18N93W. ISOLATED 
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. IN ADDITION...A STATIONARY FRONT EXTENDS 
ACROSS THE CENTRAL FLORIDA PENINSULA INTO THE NE GULF BASIN 
ALONG 28N83W TO THE COAST OF ALABAMA NEAR 30N88W PROVIDING A 
SURFACE LIFTING MECHANISM TO GENERATE SCATTERED SHOWERS AND 
THUNDERSTORMS N OF 28N BETWEEN 85W-88W. MOSAIC DOPPLER RADAR 
IMAGERY INDICATES THE TWO SEPARATE ACTIVITIES MAY BE MERGING 
OVER THE NEXT FEW HOURS AS THE COLD FRONT CONTINUES TO PROGRESS 
EASTWARD. WEST OF THE FRONT...STRONG N-NW WINDS IN THE RANGE OF 
15 TO 25 KT ARE FORECAST TO CONTINUE THROUGH THE OVERNIGHT 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 LATE EVENING. 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 32N55W CONTINUING WSW ALONG 26N67W TO 27N75W...WHERE 
LOW-LEVEL MOISTURE BECOMES MORE DIFFUSE AND A STATIONARY FRONT 
CONTINUES WESTWARD INTO THE CENTRAL FLORIDA PENINSULA ALONG 
28N80W. POSSIBLE ISOLATED SHOWERS ARE OCCURRING WITHIN 70 NM 
EITHER SIDE OF THE FRONT. AN EARLIER ASCAT PASSE DEPICTED 
STRONGER NORTHERLY WINDS UP TO 30 KT NORTH OF THE FRONT EAST OF 
70W. TO THE SE OF THIS FRONT...A WEAK AREA OF LOW LEVEL 
CONFLUENCE OF LIGHT WINDS IS ANALYZED AS A WEAK SURFACE TROUGH 
FROM 27N45W TO 21N49W WITHOUT ANY RAINSHOWER ACTIVITY 
ASSOCIATED. A SIMILAR WEAKENING TROUGH IS ALSO ANALYZED FROM 
20N47W TO 14N48W. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE 
INFLUENCE OF AN UPPER LEVEL LOW CENTERED NEAR 20N34W. 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 30W. 

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

$$

GARCIA