000
AXNT20 KNHC 312341
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST MON DEC 31 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 2245 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH CURRENTLY REMAINS SOUTH OF NW AFRICA 
EXTENDING FROM THE PRIME MERIDIAN TO 9W ALONG 4N. THE ITCZ 
BEGINS FROM 4N9W AND CONTINUES ALONG 5N18W 2N27W EQ42W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 2N-7N 
BETWEEN 20W-30W...FROM EQ-7N BETWEEN 30W-40W...AND FROM 4N-7N 
BETWEEN 40W-46W. 

...DISCUSSION...

GULF OF MEXICO...
MOSTLY FAIR CONDITIONS COVER THE GULF OF MEXICO AROUND A BROAD 
SURFACE RIDGE EXTENDING FROM A 1029 MB HIGH OVER THE W ATLC. 
LIGHT SE-S FLOW COVERS THE EASTERN GULF INCREASING IN SPEED TO 
UP TO 20 KT ALONG THE FAR WESTERN GULF NEAR THE COAST OF TEXAS. 
OVERCAST SKIES AND LIGHT SHOWERS ARE ALSO ALONG THE TEXAS COAST 
AND FARTHER INLAND. ALOFT...A BROAD UPPER RIDGE COVERS THE 
ENTIRE BASIN WITH DRY AIR COVERING THE MAJORITY EXCEPT FOR THE 
FAR NW CORNER. THE SURFACE RIDGE IS EXPECTED TO SHIFT EAST 
ALLOWING FOR A COLD FRONT TO MOVE OFF THE TEXAS COAST TOMORROW 
AFTERNOON. SHOWERS AND POSSIBLE THUNDERSTORMS ARE EXPECTED NEAR 
THE FRONT WITH STRONG NORTHERLY WINDS BEHIND IT. 

CARIBBEAN SEA...
FAIR CONDITIONS SPREAD ACROSS THE MAJORITY OF THE CARIBBEAN DUE 
TO DRY AIR ALOFT AROUND A BROAD UPPER RIDGE COVERING THE BASIN 
CENTERED NEAR 17N78W. TRADEWIND FLOW OF 15-20 KT DOMINATE AT THE 
SURFACE REACHING 25-30 KT NEAR THE COAST OF COLOMBIA. A FEW 
LOW-LEVEL SHOWERS ARE EMBEDDED WITHIN THE TRADEWIND FLOW. EXPECT 
LITTLE CHANGE OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
A BROAD UPPER LEVEL RIDGE COVERING THE GULF OF MEXICO AND 
CARIBBEAN EXTENDS OVER THE WEST ATLC SUPPORTING A BROAD SURFACE 
RIDGE ANCHORED BY A 1029 MB HIGH NEAR 32N76W. THE RIDGE IS 
PROVIDING FAIR CONDITIONS ACROSS THE MAJORITY OF THE WEST ATLC. 
TO THE EAST...AN UPPER LEVEL TROUGH ALONG 50W SUPPORTS A COLD 
FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N50W 24N60W 20N74W. 
POSSIBLE ISOLATED SHOWERS ARE WITHIN 100 NM SOUTH AND EAST OF 
THE AXIS. GALE FORCE WINDS ARE ALSO PRESENT WEST OF THE FRONT 
NORTH OF 30N. A PRE-FRONTAL TROUGH IS EAST OF THE FRONT ALONG 
32N45W 27N48W 21N50W. NO SHOWER ACTIVITY IS NEAR THE AXIS. A 
SECOND UPPER TROUGH AXIS IS ALONG 35W...BUT IS NOT CAUSING ANY 
ACTIVE WEATHER. THE REMAINDER OF THE EAST ATLC IS DOMINATED BY 
SURFACE RIDGING AROUND A 1030 MB HIGH NEAR 32N22W. THE RIDGE IS 
SUPPORTED BY AN UPPER LEVEL RIDGE ALONG 20W.

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

$$
WALTON