000 AXNT20 KNHC 132335 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST WED FEB 13 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 COAST OF LIBERIA NEAR 6N10W TO 3N14W WHERE IT TRANSITIONS INTO ITCZ AND CONTINUES ALONG 1N27W EQ37W 2S41W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 3N-6N BETWEEN 9W-17W...FROM 1N-4N BETWEEN 20W-32W...AND FROM 1S-2N BETWEEN 32W-46W. ...DISCUSSION... GULF OF MEXICO... A COLD FRONT BISECTS THE GULF OF MEXICO CURRENTLY EXTENDING FROM NE FLORIDA AT 31N81W TOWARDS THE SW GULF ALONG 26N88W 22N95W 20N97W 23N101W...AS OF 2100 UTC. A LINE OF SHOWERS/THUNDERSTORMS IS ABOUT 150 NM AHEAD OF THE FRONT WHILE A SWATH OF WIDESPREAD SHOWERS EXTENDS 90 NM TO 190 NM BEHIND...OR WEST OF THE FRONT. NW WINDS UP TO ABOUT 15-20 KT ARE IMMEDIATELY BEHIND THE FRONT ACROSS THE NORTHERN GULF...AND MAY REACH UP TO 30 KT BEHIND THE AXIS IN THE SW GULF AS INDICATED BY AN EARLIER ASCAT PASS. SOME OF THESE STRONGER WINDS ARE RESULTING FROM THE INCREASING PRESSURE GRADIENT OVER THE WESTERN GULF AS HIGH PRESSURE BUILDS BEHIND THE FRONT. ALOFT...AN ELONGATED UPPER TROUGH EXTENDING FROM THE GREAT LAKES REGION TO WESTERN TEXAS SUPPORTS THE FRONTAL BOUNDARY...WHILE AN UPPER LEVEL RIDGE COVERS THE AREA TO THE SOUTH AND EAST. THIS PATTERN IS PROVIDING MAINLY SOUTHWESTERLY FLOW ALOFT ACROSS THE GULF. DRY AIR CONTINUES TO COVER THE SE GULF WHERE MOSTLY CLEAR SKIES ARE STILL OBSERVED. THE FRONT IS EXPECTED TO CONTINUE MOVING SE ACROSS THE BASIN THROUGH THE NEXT 24 HOURS. SHOWERS ARE LIKELY NEAR THE AXIS WITH THUNDERSTORMS POSSIBLE. SURFACE RIDGING WILL CONTINUE TO BUILD IN BEHIND THE FRONT. CARIBBEAN SEA... DRY AIR ALOFT COVERS THE CARIBBEAN AROUND A BROAD UPPER RIDGE COVERING THE MAJORITY OF THE BASIN...AND AROUND AN UPPER LEVEL TROUGH IN THE CENTRAL ATLC EXTENDING TO THE FAR NORTHEASTERN CARIBBEAN. STRONG SUBSIDENCE IS ALSO NOTED IN WATER VAPOR IMAGERY OVER THE EASTERN AND CENTRAL 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 ISOLATED SHOWERS. THESE AREAS OF LOW MOISTURE ARE MAINLY FROM 15N-17N BETWEEN 69W-79W...AND FROM 15N-20N BETWEEN 82W-84W. MOSTLY 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. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. BEYOND THAT TIME...MOISTURE ASSOCIATED WITH THE COLD FRONT IN THE GULF WILL LIKELY REACH THE FAR NW CARIBBEAN. ATLANTIC OCEAN... UPPER LEVEL RIDGING COVERS THE SW NORTH ATLC EXTENDING FROM THE CARIBBEAN SUPPORTING SURFACE RIDGING AROUND A 1022 MB HIGH CENTERED NEAR 28N50W. A FEW SHOWERS/THUNDERSTORMS AHEAD OF THE COLD FRONT IN THE GULF ARE BEGINNING TO IMPACT THE FAR NW CORNER OF THE DISCUSSION AREA. ACROSS THE CENTRAL ATLC...AN UPPER LEVEL TROUGH IS APPROACHING THE AZORES ISLANDS ALONG 30W WITH AXIS CONTINUING INTO THE CENTRAL TROPICAL ATLC AND TO THE FAR EASTERN CARIBBEAN. THE UPPER TROUGH SUPPORTS A STATIONARY FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N32W AND CONTINUES ALONG 25N42W 20N56W. POSSIBLE ISOLATED SHOWERS ARE ALONG THE AXIS. THE FAR EASTERN ATLC IS DOMINATED BY SURFACE RIDGING AROUND A 1029 MB HIGH EAST OF THE AZORES NEAR 40N16W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE COVERING THE EASTERN ATLC ALONG 14W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON