000
AXNT20 KNHC 271754
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST SUN DEC 27 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 1745 UTC.

...THE ITCZ...
THE ITCZ AXIS PASSES ALONG THE CENTRAL COAST OF LIBERIA IN WEST 
AFRICA ON A ALMOST STRAIGHT LINE TO THE NORTH COAST OF BRAZIL 
NEAR THE CITY OF AMAPA. FOLLOWING ARE THE COORDINATES OF THE 
ITCZ...5.5N10W 4N20W 3N30W 2.5N40W 2N50W. NO SIGNIFICANT 
CONVECTION IS OCCURRING ALONG OR NEAR THE ITCZ...EXCEPT AN AREA 
OF WEAK TO MODERATE CONVECTION NEAR 2N50W..60 NM EAST OF THE 
CITY OF AMAPA BRAZIL.  

...DISCUSSION...

THE GULF OF MEXICO...
IN THE UPPER LEVELS OF THE ATMOSPHERE...A SUBTROPICAL JET IS 
MOVING ACROSS THE GULF OF MEXICO. THIS FEATURE IS CREATING AN 
AREA OF CONVERGENCE OVER THE CENTRAL BASIN. A TROUGH IS PLOTTED 
OVER THE CENTRAL BASIN ALONG 27N90W 23N91W 20N93W...BRINGING 
CYCLONIC SURFACE FLOW OF 15 KT TO 25 KT OVER THE ENTIRE BASIN. 
SOUTHWEST FLOW ALOFT IS BRINGING MODERATE MOISTURE TO THE 
REGION. THIS COMBINATION IS BRINGING CONVECTION TO THE 
NORTH-NORTHEAST AND CENTRAL BASIN FROM 24N TO 30N BETWEEN 82W 
AND 90W. DOPPLER RADAR IMAGERY INDICATES SCATTERED MODERATE 
SHOWERS MOVING EASTWARD ENTERING THE WEST CENTRAL COAST OF 
FLORIDA NEAR ST. PETERSBURG TO THE WESTERN TIP OF THE FLORIDA 
PANHANDLE. ANOTHER AREA OF SHOWERS IS FOUND 15 NM EAST OF 
MATAMOROS MEXICO. UNSETTLED WEATHER WILL CONTINUE ACROSS THE 
BASIN DUE TO THE PASSAGE OF THE TROUGH...WITH MORE CONVECTION 
MOVING EASTWARD PASSING ACROSS THE STATE OF FLORIDA OVER THE 
NEXT 24 HOURS.

THE CARIBBEAN SEA...

A SURFACE TROUGH IS OVER THE NNW CARIBBEAN ALONG 21N85W 19N85W 
16N85W. ANOTHER SURFACE TROUGH IS ANALYZED OVER THE WESTERN 
CARIBBEAN ALONG 19N80W 15N80W 11N80W. NEVERTHELESS...THESE TWO 
FEATURES ARE BEING SUPPRESSED BY UPPER LEVEL RIDGE OF HIGH 
PRESSURE COVERING MOST OF THE BASIN...THUS ONLY ISOLATED SHOWERS 
ARE SEEN OVER THE NW CARIBBEAN NORTH OF 15N AND WEST OF 75W. 
FROM 75W EASTWARD...STRONG SUBSIDENCE OF AIR IS DOMINATING THE 
LANDSCAPE...SUPPRESSING DEEP CONVECTION OVER THE CENTRAL AND 
EASTERN BASIN. ONLY SCATTERED SHOWERS ARE SEEN IN THIS REGION. 
MODERATE TRADEWINDS ARE NOTED OVER THE MAJORITY OF THE CARIBBEAN 
SEA. EXPECT OVER THE NEXT 24 HOURS FOR SHOWERS TO BE OVER THE 
SOUTHWEST CARIBBEAN AND PANAMA.

THE ATLANTIC OCEAN...

A COLD FRONT IS OVER THE WESTERN ATLANTIC. THE SOUTHERN HALF OF 
THIS FRONT ENTERS THE DISCUSSION AREA AS A STATIONARY FRONT 
ALONG 3272 2775 TO THE CENTRAL BAHAMAS. WEAK CONVECTION IS 60 NM 
ON EITHER SIDE OF THE FRONT. THIS FRONT IS BEEN SLOWLY PUSHED 
EASTWARD AS HIGH PRESSURE MOVES INTO THE WESTERN ATLANTIC. OVER 
THE NEXT 24 HOURS...THE STATIONARY FRONT IS EXPECTED TO GAIN 
MOMENTUM AND BECOME A COLD FRONT AND MOVE EASTWARD. OVER THE 
CENTRAL ATLANTIC...ANOTHER COLD FRONT IS ANALYZED ALONG 32N27W 
25N35W 22N40W 19N50W...BECOMING STATIONARY ALONG THE 18N LINE TO 
68W. THIS COLD FRONT IS LOOSING MOMENTUM. NEVERTHELESS...A TIGHT 
SURFACE PRESSURE GRADIENT BEHIND THE FRONT IS CREATING GALE TO 
STORM FORCE WINDS FROM NORTH OF 29N EAST OF 40W. WEAK TO 
MODERATE CONVECTION IS SEEN FROM 25N TO 29N BETWEEN 34W AND 36W. 
THE WEATHER OVER THE EAST ATLANTIC AND ELSEWHERE SOUTH OF 
16N...STRONG SUBSIDENCE OF AIR ALOFT DOMINATES THE WEATHER IN 
THESE REGIONS. EXPECT OVER THE NEXT 24 HOURS FOR THE TWO COLD 
FRONTS TO CONTINUE TO MOVE EASTWARD WITH SHOWERS AND CONVECTION. 

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

$$

GARCIA