000
AXNT20 KNHC 281737
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST MON DEC 28 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1500 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 05N09W TO 06N14W TO 02N45W TO 
EQ50W. SCATTERED MODERATE CONVECTION WITHIN 60 NM S OF AXIS 
BETWEEN 37W AND 39W. SCATTERED MODERATE CONVECTION WITHIN 60 NM 
N OF AXIS W OF 45W.

...DISCUSSION...

THE GULF OF MEXICO...
A SURFACE TROUGH EXTENDS REMAINS OVER THE WESTERN GULF OF MEXICO 
FROM 27N97W TO 19N92W. 1035 MB SURFACE HIGH PRES IS CENTERED 
OVER CENTRAL TEXAS. BUOYS AND LAND BASED OBSERVATIONS INDICATE 
FRESH TO STRONG NORTHERLY FLOW ON THE EAST SIDE OF THE HIGH 
PRES...DELIVERING COOL AND RELATIVELY DRY AIR ACROSS MUCH OF 
THE CENTRAL AND EASTERN GULF OF MEXICO. DENSE LOW TO MID LEVEL 
CLOUDS WITH CEILINGS OF 5 TO 8 THOUSAND FEET COVER THE FAR 
WESTERN GULF W OF THE TROUGH FROM S TEXAS TO THE BAY OF 
CAMPECHE. BY TUE NIGHT...LOW PRES WILL FORM ALONG THE TROUGH 
OVER THE NW GULF AND SHIFT NE TOWARD LOUISIANA BY WED.

THE CARIBBEAN SEA...
A DEEP LAYER TROUGH EXTENDING FROM THE CENTRAL ATLC TO THE SE 
CARIBBEAN IS SHIFTING E AHEAD OF AN UPPER LEVEL ANTICYCLONE 
BUILDING OVER THE WESTERN CARIBBEAN. SUBSIDENT DRY AIR IN THE NW 
FLOW BETWEEN THESE FEATURES IS MAINTAINING MOSTLY SUNNY 
CONDITIONS ACROSS THE EASTERN AND CENTRAL CARIBBEAN. AT THE 
SURFACE...HIGH PRES OVER THE S CENTRAL U.S. IS MAINTAINING 
MODERATE NORTHERLY FLOW OVER THE NW CARIBBEAN. MEANWHILE 
EASTERLY TRADES DOMINATE THE EASTERN AND CENTRAL CARIBBEAN DUE 
TO HIGH PRES OVER THE N CENTRAL ATLC. A LINE OF CLOUDS FROM SE 
CUBA TO EASTERN HONDURAS MARKS THE CONVERGENCE OF THE NORTHERLY 
AND EASTERLY WINDS. MEANWHILE NORTHERLY SWELL WITH PERIODS TO 14 
SECONDS AND HEIGHTS TO 12 FT IS PUSHING THROUGH THE MONA AND 
ANEGADA PASSAGES.

ATLANTIC OCEAN S OF 31N...
A REX BLOCK PATTERN OVER WEST AFRICA IS BREAKING DOWN IN ADVANCE 
OF A DEEP LAYER TROUGH EXTENDING FROM THE N CENTRAL ATLC THROUGH 
THE SE CARIBBEAN. AN ASSOCIATED COLD FRONT EXTENDS FROM ROUGHLY 
THE CANARY ISLANDS TO 16N45W...THEN STATIONARY TO NE OF THE 
LEEWARD ISLANDS. WINDSAT DATA SHOW STRONG TO NEAR GALE FORCE NW 
WINDS BEHIND THE FRONT IN THE AREA MAINLY N OF 26N E OF 50W.  
OTHERWISE SCATTEROMETER DATA SHOW MODERATE TO FRESH NORTHERLY 
WINDS PREVAILING BETWEEN THE FRONT AND A 1027 MB HIGH PRES 
CENTERED OVER THE N CENTRAL ATLC. SCATTEROMETER DATA ALSO SHOW 
AN AREA OF FRESH TRADES S OF THE HIGH PRES OFF THE COAST OF THE 
GUYANA. EAST OF THE HIGH PRES...FRONTAL BOUNDARY REMAINS STALL 
FROM 31N68W TO CENTRAL BAHAMAS...PROMPTING SCATTERED SHOWERS 
BETWEEN THE SOUTHERN BAHAMAS AND BERMUDA. LOOKING AHEAD THROUGH 
TUE...THE COLD FRONT NEAR THE CANARY ISLANDS WILL CONTINUE SE 
TOWARD THE CAPE VERDE ISLANDS AHEAD OF THE UPPER TROUGH...AND 
THE STATIONARY FRONT THROUGH THE BAHAMAS WILL START TO MOVE EAST 
AHEAD OF AN UPPER LEVEL TROUGH PUSHING OFF THE U.S. EAST COAST.

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

$$
CHRISTENSEN