000
AXNT20 KNHC 212342
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT JAN 21 2012

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE ITCZ EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 
8N13W ALONG 5N18W 2N25W 1N40W ACROSS THE EQUATOR NEAR 45W TO 
INLAND OVER SOUTH AMERICA. CLUSTERS OF SCATTERED MODERATE/ 
ISOLATED STRONG CONVECTION ARE FROM 1N-7N BETWEEN 2W-15W AND 
WITHIN 180 NM N OF THE ITCZ BETWEEN 32W-39W. 

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH IS MOVING RAPIDLY ACROSS THE E CONUS AND THE N 
GULF N OF 26N SUPPORTING A COLD FRONT THAT AT 21/2100 UTC ENTERS 
THE GULF NEAR GALVESTON TEXAS ALONG 28N96W TO INLAND OVER S 
TEXAS S OF CORPUS CHRISTI NEAR 27N98W TO S OF LAREDO TEXAS. 
HEAVY SHOWERS/THUNDERSTORMS ARE INLAND OVER S ALABAMA ACROSS 
CENTRAL GEORGIA TO OVER THE E PORTION OF SOUTH CAROLINA AND ARE 
APPROACHING THE FLORIDA PANHANDLE. A SURFACE RIDGE ANCHORED IN 
THE W ATLC EXTENDS AN AXIS ACROSS THE FLORIDA PENINSULA TO NEAR 
26N90W WITH SOUTHERLY RETURN FLOW E OF THE FRONT. AN UPPER RIDGE 
COVERS THE REMAINDER OF THE GULF AND MEXICO INTO TEXAS DRAWING 
UPPER LEVEL MOISTURE ACROSS MEXICO AND THE GULF WITH LOW LEVEL 
MOISTURE PRESENT ARE GIVING MOST OF THE GULF PARTLY CLOUDS SKIES 
THIS EVENING BUT LITTLE IN THE WAY OF SHOWERS. THE COLD FRONT 
WILL STALL AND DRIFT N OF THE AREA LATER TONIGHT. A SECOND COLD 
FRONT WILL REACH THE NW GULF EARLY MON AND WEAKEN AS IT MOVES 
ACROSS THE N GULF MON THROUGH TUE. A THIRD COLD FRONT WILL MOVE 
OFF THE TEXAS COAST THU.

CARIBBEAN SEA...
THE UPPER RIDGE OVER THE GULF OF MEXICO EXTENDS OVER THE NW 
CARIBBEAN WITH NEAR ZONAL WESTERLY FLOW ALOFT ACROSS THE 
REMAINDER OF THE BASIN. WATER VAPOR IMAGERY SHOWS MODERATE TO 
STRONG SUBSIDENCE AND DRY STABLE AIR ALOFT ACROSS THE ENTIRE 
BASIN. EASTERLY TRADE WINDS ARE ACROSS THE CARIBBEAN WITH THE 
STRONGEST WINDS ALONG THE COAST OF COLOMBIA. THESE TRADE WINDS 
ARE USHERING IN LOW LEVEL FAST MOVING CLOUDS AND POSSIBLE 
ISOLATED SHOWERS GIVING THE CARIBBEAN MOSTLY FAIR CONDITIONS 
THIS EVENING. LITTLE CHANGE IS EXPECTED THROUGH THU. 

ATLANTIC OCEAN...
A SURFACE RIDGE DOMINATES THE W ATLC ANCHORED BY A 1025 NEAR 
BERMUDA AND EXTENDING A RIDGE AXIS ACROSS FLORIDA INTO THE GULF 
OF MEXICO. AN UPPER TROUGH COVERS THE CENTRAL ATLC SUPPORTING A 
WEAKENING FRONTAL BOUNDARY THAT EXTENDS FROM A 1014 MB LOW NEAR 
28N44W ALONG 26N39W 20N41W TO 16N47W AND A STRONGER COLD FRONT 
THAT EXTENDS FROM A 1015 MB LOW NEAR 32N51W ALONG 29N50W 25N54W 
TO 24N61W. ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS ARE N OF 
27N BETWEEN 36W-44W WITH SCATTERED SHOWERS WITHIN 60/75 NM SE OF 
THE STRONG COLD FRONT. A SURFACE RIDGE DOMINATES THE E ATLC N 
OF 16N E OF 38W ANCHORED BY A 1033 MB HIGH NEAR THE AZORES. 
SURFACE RIDGE OVER THE W ATLC WILL PERSIST THROUGH MON. WEAK 
COLD FRONT WILL MOVE OFF THE GEORGIA COAST EARLY TUE AND STALL 
ALONG THE N PERIPHERY OF THE W ATLC BY EARLY THU BEFORE 
DISSIPATING. THE WEAK CENTRAL ATLC FRONTAL BOUNDARY IS EXPECTED 
TO DISSIPATE BY SUN NIGHT AS THE STRONG COLD FRONT WILL CONTINUE 
TO MOVE SLOWLY EASTWARD BECOMING A SURFACE TROUGH SUN NIGHT THEN 
STALLING ALONG 45W THROUGH THU.  

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

$$
PAW