000 AXNT20 KNHC 122341 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST TUE FEB 12 2013 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. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE SOUTHERN COAST OF SIERRA LEONE NEAR 7N12W TO 5N20W. THE ITCZ BEGINS AT 5N20W AND CONTINUES ALONG 1N30W EQ44W 2S47W. A CLUSTER OF MODERATE/STRONG CONVECTION IS FROM 3N-4N BETWEEN 10W-12W...AND FROM 2N-4N BETWEEN 23W-25W. SCATTERED MODERATE CONVECTION IS FROM 3N-6N BETWEEN 37W-50W. ...DISCUSSION... GULF OF MEXICO... WHILE UPPER LEVEL RIDGING CURRENTLY COVERS THE GULF OF MEXICO FOR THE TIME BEING...AN UPPER LEVEL TROUGH IS APPROACHING AND SUPPORTS A 1008 MB SURFACE LOW OVER LOUISIANA NEAR 31N93W...AS OF 2100 UTC. A COLD FRONT EXTENDS FROM THE LOW CENTER TO 25N98W CONTINUING INTO NORTHEAST MEXICO. A WARM FRONT DRAPES ACROSS THE NE GULF COAST STATES FROM THE LOW CENTER EASTWARD TO NEAR 31N83W. POSSIBLE ISOLATED SHOWERS ARE ALONG THE COLD FRONT WITH SCATTERED SHOWERS WITHIN 60 NM OF THE WARM FRONT...ESPECIALLY OVER THE FLORIDA PANHANDLE. THE REMAINDER OF THE GULF OF MEXICO IS UNDER WEAK SURFACE RIDGING EXTENDING FROM THE WEST ATLC. THE SURFACE RIDGING COUPLED WITH DRY AIR ALOFT IS PROVIDING FAIR CONDITIONS ACROSS MUCH OF THE SOUTHERN AND CENTRAL PORTIONS OF THE BASIN. MAINLY SOUTHERLY FLOW OF 15-20 KT IS EAST OF THE FRONT SHIFTING TO NW FLOW WEST OF THE FRONT. EXPECT THE FRONT TO MOVE THROUGH THE BASIN OVER THE NEXT COUPLE OF DAYS WITH SHOWERS AND THUNDERSTORMS POSSIBLE NEAR THE AXIS. CARIBBEAN SEA... DRY AIR ALOFT COVERS THE CARIBBEAN AROUND A BROAD UPPER RIDGE COVERING THE WESTERN HALF OF THE BASIN CENTERED OVER GUATEMALA...AND AROUND AN UPPER LEVEL TROUGH IN THE CENTRAL ATLC EXTENDING TO THE FAR EASTERN CARIBBEAN. STRONG SUBSIDENCE IS ALSO NOTED IN WATER VAPOR IMAGERY OVER THE EASTERN CARIBBEAN. THE DRY AIR AND SUBSIDENCE ALOFT IS HELPING PROVIDE FAIR CONDITIONS ACROSS THE BASIN WITH ONLY A FEW AREAS OF LOW LEVEL MOISTURE AND POSSIBLE ISOLATED SHOWERS. THESE AREAS OF LOW MOISTURE ARE MAINLY FROM 15N-17N EAST OF JAMAICA TO THE LEEWARD ISLANDS. THIS MOISTURE IS ALL THAT REMAINS OF A SHEAR AXIS THAT IS QUICKLY DISSIPATING WITH ONLY A SMALL PORTION EXTENDING FROM THE LEEWARD ISLANDS TO 15N64W. MAINLY 15-20 KT TRADEWIND FLOW DOMINATES WITH A SMALL AREA OF 25 KT WINDS NEAR THE COAST OF COLOMBIA. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... UPPER LEVEL RIDGING COVERS THE SW NORTH ATLC EXTENDING FROM THE CARIBBEAN SUPPORTING SURFACE RIDGING AROUND A 1024 MB HIGH CENTERED NEAR 31N54W. AN UPPER LEVEL TROUGH TO THE EAST ALONG 42W SUPPORTS A COLD FRONT THAT ENTERS THE AREA NEAR 32N38W AND CONTINUES TO 23N45W WHERE IT BECOMES A SHEAR AXIS TO THE NE CARIBBEAN NEAR 16N62W. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE WITHIN 160 NM EAST OF THE COLD FRONT WITH POSSIBLE ISOLATED SHOWERS NEAR THE SHEAR AXIS. THE FAR EASTERN ATLC IS DOMINATED BY SURFACE RIDGING AROUND A 1031 MB HIGH EAST OF THE AZORES NEAR 38N19W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE COVERING THE EASTERN ATLC ALONG 18W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON