000 AXNT20 KNHC 291253 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SAT DEC 29 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1045 UTC. ...THE ITCZ/THE MONSOON TROUGH... MONSOON TROUGH EXTENDS ACROSS WEST AFRICA TO COAST OF LIBERIA WHERE IT TRANSITIONS INTO ITCZ ALONG 06N10W 03N30W EQ49W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 3N-7N BETWEEN 23W-38W AND FROM EQ-2N BETWEEN 31W-36W. ...DISCUSSION... GULF OF MEXICO... AS OF 0900 UTC...A COLD FRONT EXTENDS FROM THE FLORIDA PANHANDLE NEAR 31N84W TO THE EASTERN COAST OF MEXICO ALONG 24N89W 22N95W 19N96W. STRONG SHOWERS/ISOLATED THUNDERSTORMS ARE UP TO 150 NM EAST OF THE AXIS NORTH OF 24N. ISOLATED SHOWERS ARE UP TO 120 NM AHEAD OF THE FRONT ELSEWHERE. STRONG NORTHWEST-NORTH WINDS OF 20-25 KT ARE OBSERVED BEHIND THE FRONT. THE FRONT IS SUPPORTED BY AN UPPER LEVEL TROUGH MOVING THROUGH THE MISSISSIPPI VALLEY WITH A SHORTWAVE DIPPING SOUTH OVER ALABAMA AND GEORGIA. BROAD UPPER RIDGING COVERS THE SOUTHERN GULF ACCOMPANIED BY DRY AIR...WHICH IS HELPING PROVIDE FAIR CONDITIONS ACROSS THE SE GULF. THE FRONT IS EXPECTED TO CONTINUE TO PUSH SE ACROSS THE BASIN WITH SURFACE RIDGING BUILDING IN BEHIND IT. THE RIDGE WILL THEN SHIFT EAST ALLOWING THE NEXT FRONTAL SYSTEM TO MOVE INTO THE NW GULF BY EARLY TUESDAY. THE CARIBBEAN SEA... FAIR CONDITIONS AND TRADEWIND FLOW OF 15-20 KT SPREAD ACROSS THE MAJORITY OF THE CARIBBEAN DUE TO DRY AIR ALOFT AROUND A BROAD UPPER LEVEL RIDGE COVERING THE BASIN. ONLY A FEW SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE IN THE FAR SW GULF ACROSS COSTA RICA AND PANAMA ASSOCIATED WITH THE MONSOON TROUGH EXTENDING ALONG 10N. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24 HOURS. A COLD FRONT CURRENTLY IN THE GULF OF MEXICO IS EXPECTED TO REACH THE FAR NW CARIBBEAN EARLY SUNDAY. THE ATLANTIC OCEAN... BROAD UPPER LEVEL RIDGING COVERS THE SW NORTH ATLC SUPPORTING A WEAK SURFACE RIDGE AROUND A 1021 MB HIGH NEAR 29N65W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE MOVING ACROSS NORTHERN FLORIDA OVER ATLC WATERS NORTH OF 28N WEST OF 74W ASSOCIATED WITH A COLD FRONT IN THE GULF OF MEXICO. AN UPPER LEVEL TROUGH OVER THE NW ATLC CONTINUES TO SUPPORT A WEAK COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N55W AND CONTINUES TO 26N65W. POSSIBLE ISOLATED SHOWERS ARE ALONG THE AXIS. A WEAK 1021 MB SURFACE HIGH IS ALSO TO THE EAST OF THE COLD FRONT NEAR 29N52W HELPING PROVIDE FAIR CONDITIONS ACROSS MUCH OF THE CENTRAL ATLC. FARTHER EAST...A NEARLY CUT-OFF UPPER LEVEL LOW NEAR 25N38W SUPPORTS A 1016 MB SURFACE LOW NEAR 23N43W WITH AN ASSOCIATED SURFACE TROUGH EXTENDING THROUGH THE CENTER ALONG 30N40W 20N43W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE MAINLY EAST OF THE TROUGH AXIS FROM 22N-26N BETWEEN 37W-40W. THE REMAINDER OF THE EASTERN ATLC IS DOMINATED BY SURFACE RIDGING AROUND A 1030 MB HIGH CENTERED OVER NW AFRICA. ALOFT...AN UPPER LEVEL RIDGE COVERS THE AREA ALONG 22W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON