000 AXNT20 KNHC 230550 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST SUN DEC 23 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 6N10W TO 4N12W WHERE THE ITCZ CONTINUES ALONG 4N18W 5N36W TO SOUTH AMERICA NEAR 4N51W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 1N-6N BETWEEN 15W-23W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 90 NM N OF THE ITCZ BETWEEN 23W-27W...FROM 2N-4N BETWEEN 29W-36W... AND FROM 5N-7N BETWEEN 37W-44W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER RIDGE EXTENDS FROM THE E PACIFIC REGION ACROSS MEXICO TO OVER THE CENTRAL CONUS COVERING MOST OF THE GULF OF MEXICO AND DEEPENING THE BROAD UPPER TROUGH THAT COVERS THE W ATLC INTO THE CARIBBEAN. A SURFACE RIDGE COVERS THE GULF ANCHORED BY A 1026 MB HIGH ALONG THE N GULF COAST NEAR MOBILE ALABAMA. THE SOUTHERLY RETURN FLOW OVER THE W GULF IS GENERATING ISOLATED SHOWERS WITHIN 90 NM ALONG THE W GULF COAST FROM E OF VERACRUZ MEXICO TO VERMILION BAY LOUISIANA. THE REMAINDER OF THE GULF IS UNDER CLEAR SKIES AGAIN TONIGHT. HIGH PRESSURE WILL SHIFT E THROUGH SUN. A COLD FRONT WILL APPROACH THE N GULF MON THEN STALL AS A STATIONARY FRONT N OF 28N MON NIGHT AND TUE. A STRONGER COLD FRONT WILL RACE SE ACROSS THE REGION TUE AND WED. CARIBBEAN SEA... THE BROAD UPPER TROUGH OVER THE W ATLC EXTENDS S OVER THE W CARIBBEAN W OF 65W SUPPORTING A COLD FRONT IN THE W ATLC ACROSS PORTIONS OF HAITI TO NEAR 19N74W WHERE A SHEAR LINE CONTINUES TO INLAND OVER CENTRAL NICARAGUA NEAR 13N84W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 200 NM E OF THE SHEAR LINE. A BROAD UPPER RIDGE AXIS IS E OF THE LESSER ANTILLES TO OVER THE CENTRAL ATLC COVERING THE REMAINDER OF THE E CARIBBEAN. SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS OVER THE E CARIBBEAN FROM VENEZUELA TO OVER THE GREATER ANTILLES BETWEEN 63W-70W WITH SCATTERED SHOWERS S OF 15N E OF 74W TO THE WINDWARD ISLANDS. STRONG SUBSIDENCE AND DRY STABLE AIR ALOFT COVER THE CARIBBEAN W OF 70W LEAVING THE AREA W OF THE SHEAR LINE UNDER CLEAR SKIES TONIGHT. SHEAR LINE WILL MOVE E FROM THE MONA PASSAGE TO PANAMA BY SUN NIGHT. HIGH PRESSURE BUILDING OVER THE W ATLC WILL SUPPORT FRESH TO STRONG TRADE WINDS ACROSS THE CENTRAL CARIBBEAN THROUGH THE MIDDLE OF NEXT WEEK. ANOTHER FRONT WILL MOVE INTO THE NW CARIBBEAN NEXT THU. ATLANTIC OCEAN... THE BROAD UPPER TROUGH COVERS THE W ATLC W OF 60W SUPPORTING A COLD FRONT THAT ENTERS THE W ATLC NEAR 32N59W ALONG 25N65W TO OVER PORTIONS OF HAITI TO NEAR 19N74W WHERE IT CONTINUES AS A SHEAR LINE OVER THE CARIBBEAN. ISOLATED SHOWERS ARE POSSIBLE WITHIN 90 NM W OF THE FRONT. THE SURFACE RIDGE OVER THE GULF OF MEXICO CONTINUES TO BUILD E OVER THE W ATLC W OF THE FRONT. THE WEAK SURFACE RIDGE IS OVER THE REMAINDER OF THE W INTO THE CENTRAL ATLC AND IS ANCHORED BY A 1018 MB HIGH NEAR 24N59W. AN UPPER TROUGH COVERS THE E ATLC N OF 20N E OF 40W SUPPORTING ANOTHER COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N28W CONTINUING ALONG 25N32W TO 19N43W. A SURFACE TROUGH TRAILS THE FRONT EXTENDING FROM 30N32W ALONG 27N36W TO 25N43W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 200 NM E OF THE FRONT N OF 23N. W ATLC COLD FRONT WILL WEAKEN INTO A SHEAR LINE N OF THE LEEWARD ISLANDS SUN AND SUN NIGHT. HIGH PRESSURE BUILDING BEHIND THE FRONT WILL SHIFT E ALONG 30N. A STRONG COLD FRONT IS EXPECTED MOVE OFF THE NE FLORIDA COAST LATE TUE REACHING FROM 31N71W TO THE STRAITS OF FLORIDA BY LATE WED AND FROM 31N65W TO CENTRAL CUBA BY LATE THU. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW