000 AXNT20 KNHC 070000 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST THU JAN 06 2011 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...ITCZ... THE ITCZ AXIS IS ANALYZED FROM THE SOUTHERN COAST OF LIBERIA NEAR 4N8W EXTENDING WESTWARD ALONG EQ20W 1S30W EQ40W 3S50W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 3S TO 5N W OF 30W. SIMILAR CONVECTION IS WITHIN 30 NM EITHER SIDE OF THE AXIS BETWEEN 15W AND 23W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER LEVEL TROUGH COVERS THE ESE CONUS. AN UPPER LEVEL SHORTWAVE IS EMBEDDED IN THE TROUGH AND IS MOVING OFF THE SE US SEABOARD...SUPPORTING A COLD FRONT THAT ENTERS THE DISCUSSION AREA THROUGH FLORIDA...EXTENDING FROM THE SOUTHERN TIP OF THE PENINSULA NEAR 25N81W SOUTHWEST TO 22N91W. DOPPLER RADAR IMAGERY SHOWS A WELL DEFINED LINE OF MODERATE TO HEAVY SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 20 NM ALONG THE FRONT...AS IT MOVES THROUGH THE FAR SE GULF AND THE FLORIDA STRAITS. MARINE OBS LOCATED IN THE VICINITY OF THE PASSING FRONT INDICATED GUSTY WINDS UP TO 25 KT NEAR THE FRONTAL CONVECTION. AS THIS SYSTEM MOVES OUT OF THE AREA TONIGHT...AN UPPER LEVEL RIDGE OF HIGH PRESSURE BUILDS ACROSS THE REGION...PROVIDING FAIR WEATHER CONDITIONS ELSEWHERE ACROSS THE GULF FOR THE NEXT DAY OR SO. CARIBBEAN SEA... THE UPPER LEVELS OF THE CARIBBEAN SEA ARE DOMINATED BY STRONG SUBSIDENCE AND DRY STABLE AIR ALOFT NOTED ON WATER VAPOR IMAGERY. CONSEQUENTLY...GENERALLY FAIR WEATHER CONDITIONS ARE OCCURRING ACROSS MUCH OF THE CARIBBEAN AND NO SURFACE FEATURES ARE ANALYZED AT THE PRESENT TIME. MARINE OBS COMBINED WITH EARLIER ASCAT PASSES INDICATE A VERY LOOSE PRESSURE GRADIENT ACROSS THE REGION WITH A 10-15 KT TRADE WIND FLOW S OF 18N E OF 83W. THIS FLOW STARTS TURNING NE ALONG 80W CREATING A WEAK CONVERGENCE ZONE IN THE FAR SW CARIBBEAN...SUPPORTING LINES OF WEAK SHOWERS WITHIN 150 NM OFF THE COASTS OF NICARAGUA...COSTA RICA...AND PANAMA W OF 80W. A COLD FRONT...CURRENTLY MOVING ACROSS THE SE GULF OF MEXICO...IS EXPECTED TO ENTER THE NW CARIBBEAN OVER THE NEXT 6 HOURS WITH SCATTERED CONVECTION. ATLANTIC OCEAN... A BROAD UPPER LEVEL TROUGH COVERS THE ESE CONUS AND NW ATLC. AN UPPER LEVEL SHORTWAVE IS EMBEDDED IN THE TROUGH AND IS MOVING OFF THE SE US SEABOARD...SUPPORTING A 993 MB LOW PRESSURE SYSTEM NEAR 36N65W. A COLD FRONT EXTENDS SW FORM THE LOW CENTER TO THE FLORIDA PENINSULA ALONG 30N70W 25N80W. SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS ARE WITHIN 140 NM EAST OF THE FRONT ALONG WITH DEVELOPING GALE FORCE WINDS N OF 28N EAST OF THE FRONT TO 65W. SEAS ARE EXPECTED TO RANGE FROM 8-11 FT IN THIS AREA. BROAD UPPER LEVEL RIDGING COVERS THE CENTRAL ATLANTIC ANCHORED BY A NEARLY STATIONARY 1019 MB HIGH NEAR 28N40W. THIS FEATURE IS PROVIDING MOSTLY FAIR WEATHER CONDITIONS BETWEEN 25W AND 60W. DESPITE GIVEN CONDITIONS...A SET OF TWO WEAK SURFACE TROUGHS ARE EMBEDDED IN THE ANTI-CYCLONIC FLOW. THE FIRST ONE IS ANALYZED FROM 19N53W TO 16N55W. THE SECOND ONE IS ANALYZED FROM 22N42W TO 17N43W. SCATTERED MODERATE SHOWERS ARE DEVELOPING WITHIN 100 NM EITHER SIDE OF THE TROUGHS N OF 17N. THESE TWO TROUGHS ARE EXPECTED TO DISSIPATE OVER THE NEXT 24 HOURS. OVER THE EASTERN N ATLC...A BROAD UPPER LEVEL TROUGH SWINGS ACROSS THE NE ATLC SUPPORTING A WEAKENING COLD FRONT SITUATED N OF THE CANARY ISLANDS FROM 32W15W TO 23N30W. THE UPPER SUPPORT FOR THE FRONT IS MOVING NE OUT OF THE ATLC...AND THE FRONT WILL MAKE SLOW PROGRESS TO THE EAST OVER THE NEXT 24 HOURS. LOOK FOR THE WEST ATLC COLD FRONT TO CONTINUE TO MOVE EASTWARD WITH CONVECTION AND GALE FORCE WINDS AHEAD OF IT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA