000 AXNT20 KNHC 272341 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST THU DEC 27 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. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS WEST AFRICA TO COASTAL LIBERIA NEAR 5N9W TO 4N16W. THE ITCZ BEGINS FROM 4N16W AND CONTINUES ALONG 3N29W 1S40W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-6N BETWEEN 14W-17W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 1N-5N BETWEEN 30W-36W...AND FROM 3N-6N BETWEEN 38W-43W. ...DISCUSSION... GULF OF MEXICO... MAINLY ZONAL WESTERLY FLOW ALOFT COVERS THE GULF OF MEXICO AROUND A BROAD UPPER RIDGE COVERING THE CARIBBEAN AND THE SW NORTH ATLC. THE UPPER RIDGE SUPPORTS A WEAK SURFACE RIDGE ACROSS THE EASTERN GULF...WHICH IS HELPING PROVIDE FAIR WEATHER EAST OF 90W. AN APPROACHING UPPER TROUGH CURRENTLY OVER THE WESTERN CONUS IS BEGINNING TO SUPPORT A FORMING FRONTAL SYSTEM ALONG THE TEXAS COAST. AS OF 2100 UTC...A 1009 MB SURFACE LOW IS ON THE TEXAS COAST NEAR 27N98W WITH A STATIONARY FRONT EXTENDING THROUGH THE LOW CENTER HUGGING THE COASTLINE OF TEXAS. THE FRONT WILL REMAIN STATIONARY FOR ABOUT 24 HOURS BEFORE MOVING INTO THE GULF AS A COLD FRONT. ISOLATED SHOWERS ARE CURRENTLY NEAR THE TEXAS COAST AND A FEW AREAS INLAND. WHILE WINDS ARE LIGHT ACROSS THE EASTERN GULF...THEY INCREASE TO 20-25 KT OVER THE WESTERN GULF AHEAD OF THE FRONT. THE SURFACE RIDGE IS EXPECTED TO SHIFT EAST ALLOWING THE FRONTAL BOUNDARY ON THE TEXAS COAST TO MOVE INTO THE GULF OF MEXICO OVER THE WEEKEND. SURFACE RIDGING WILL RE-ESTABLISH OVER THE BASIN BY SUNDAY AND INTO THE FIRST PART OF NEXT WEEK. CARIBBEAN SEA... AS OF 2100 UTC...THE COLD FRONT IN THE WEST ATLC CONTINUES INTO THE NW CARIBBEAN AS A STATIONARY FRONT. THE AXIS CURRENTLY EXTENDS FROM CENTRAL CUBA NEAR 22N80W TO HONDURAS AT 16N88W. ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS ARE WITHIN 150 NM EITHER SIDE OF THE AXIS. TRADEWIND FLOW OF 15-20 KT DOMINATES THE REMAINDER OF THE CARIBBEAN ALONG WITH MOSTLY CLEAR SKIES DUE TO DRY AIR ALOFT AROUND A BROAD UPPER LEVEL RIDGE COVERING THE BASIN. THE FRONT IS EXPECTED TO DISSIPATE WITH MOISTURE REMAINING IN THE NW CARIBBEAN AND DRIFTING NW INTO THE SE GULF OF MEXICO. ATLANTIC OCEAN... A DEEP LAYER TROUGH OVER THE NW ATLC SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N68W TO THE CENTRAL BAHAMAS NEAR 24N76W CONTINUING TO THE NW CARIBBEAN. POSSIBLE ISOLATED SHOWERS ARE ALONG THE FRONT AXIS. DUE TO DRY AIR ALOFT ON EITHER SIDE OF THE FRONT...FAIR CONDITIONS ARE NOTED ELSEWHERE ACROSS THE WESTERN ATLC. A BROAD UPPER LEVEL RIDGE COVERING THE CARIBBEAN EXTENDS INTO THE CENTRAL ATLC ALONG 54W SUPPORTING A WEAK SURFACE RIDGE AROUND A 1021 MB HIGH NEAR 28N55W. FARTHER EAST...A NEARLY CUT-OFF UPPER LEVEL LOW/TROUGH ALONG 41W SUPPORTS A WEAK 1015 MB SURFACE LOW NEAR 28N42W. A SURFACE TROUGH EXTENDS NORTHWARD FROM THE LOW TO 33N38W. A SECOND SURFACE TROUGH WRAPS AROUND THE LOW CENTER CONTINUING TO THE SW ALONG 18N43W 8N52W. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE NEAR THE LOW CENTER AND ALONG THE SURFACE TROUGH TO THE NORTH. SIMILAR ACTIVITY IS ALSO TO THE EAST NORTH OF 24N BETWEEN 34W-39W. THE REMAINDER OF THE EASTERN ATLC IS DOMINATED BY SURFACE RIDGING EXTENDING FROM A HIGH CENTER OVER PORTUGAL. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE ALONG 18W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON