000 AXNT20 KNHC 232359 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SAT FEB 23 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 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM A 1006 MB LOW OVER GUINEA-BISSAU IN AFRICA NEAR 12N15W TO 6N18W. THE ITCZ BEGINS AT 6N18W AND CONTINUES ALONG 1N30W EQ36W 2S47W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-5N BETWEEN 17W-24W...FROM 1N-4N BETWEEN 27W-31W...AND FROM 2S-2N BETWEEN 33W-39W. SCATTERED MODERATE CONVECTION IS ALSO NORTH OF THE AXIS FROM 2N-7N BETWEEN 42W-50W. ...DISCUSSION... GULF OF MEXICO... THE NORTHWEST HALF OF THE GULF OF MEXICO CONTINUES TO BE IMPACTED BY A FRONTAL BOUNDARY. AS OF 2100 UTC...A STATIONARY FRONT EXTENDS FROM THE FLORIDA PANHANDLE NEAR 31N85W TO 27N94W 20N96W. A PRE-FRONTAL TROUGH IS EAST OF THE FRONT IN THE NE GULF ALONG 31N83W TO 29N87W. RADAR IMAGERY AND LIGHTNING DATA INDICATE HEAVY SHOWERS AND ISOLATED THUNDERSTORMS ARE BETWEEN THE SURFACE TROUGH AND FRONT CONTINUING 80 NM NW OF THE FRONT. SCATTERED SHOWERS ARE WITHIN 50 NM EITHER SIDE OF THE FRONTAL BOUNDARY ELSEWHERE NORTH OF 25N. POSSIBLE ISOLATED SHOWERS ARE SOUTH OF 25 NORTH NEAR THE FRONT AXIS. THE FRONT IS SUPPORTED BY A SHORTWAVE UPPER TROUGH OVER ARKANSAS...WHICH IS EMBEDDED WITHIN A LARGER SCALE UPPER TROUGH/LOW OVER THE GREAT LAKES REGION. THE REMAINDER OF THE BASIN IS COVERED BY A BROAD UPPER TROUGH WITH AXIS ALONG 74W. DRY AIR ALOFT COVERS THE AREA SE OF THE FRONT...WHICH IS HELPING PROVIDE FAIR CONDITIONS AND WEAK SURFACE RIDGING. SOUTHERLY WINDS OF 10-15 KT ARE PRESENT ACROSS THIS AREA WITH SLIGHTLY STRONGER NORTHERLY FLOW WEST OF THE FRONT. THE FRONT WILL REMAIN RELATIVELY STATIONARY FOR THE NEXT 6-12 HOURS BEFORE DRIFTING EAST WHILE THE PORTION IN THE SW GULF LIFTS NORTH AS A WARM FRONT AHEAD OF THE NEXT STRONG FRONTAL SYSTEM EXPECTED TO ENTER THE GULF ON MONDAY. CARIBBEAN SEA... FAIR CONDITIONS SPREAD ACROSS THE CARIBBEAN DUE TO DRY AIR ALOFT COVERING THE BASIN AROUND A BROAD UPPER LEVEL RIDGE ALONG 74W. WATER VAPOR IMAGERY ALSO INDICATES STRONG SUBSIDENCE IS ACROSS THE CENTRAL CARIBBEAN. MOSTLY CLEAR SKIES ARE PRESENT WITH A FEW LOW LEVEL CLOUDS AND POSSIBLE ISOLATED SHOWERS EMBEDDED WITHIN THE TRADEWIND FLOW OF 15-20 KT. SHOWERS ARE MOST LIKELY NORTH OF VENEZUELA IN THE SOUTHERN WINDWARD ISLANDS. DUE TO A STRONG PRESSURE GRADIENT BETWEEN A HIGH PRESSURE CENTER TO THE NORTH AND LOW PRESSURE OVER COLOMBIA...GALE FORCE WINDS ARE PRESENT JUST OFF THE NORTHERN COAST OF COLOMBIA. THE WINDS ARE EXPECTED TO DIMINISH BELOW GALE FORCE WITHIN THE NEXT 12-24 HOURS. LITTLE CHANGE IS EXPECTED ELSEWHERE OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE DOMINATES THE WEST ATLC WITH AXIS ALONG 74W. IT SUPPORTS A SURFACE RIDGE ANCHORED BY A PAIR OF 1022 MB HIGHS NEAR 30N66W AND 33N64W. A DEEP LAYERED TROUGH IN THE CENTRAL ATLC ALONG 42W SUPPORTS A STORM-FORCE SURFACE LOW CENTER WELL NORTH OF THE DISCUSSION AREA NEAR 41N44W. AN ASSOCIATED COLD FRONT ENTERS THE AREA NEAR 32N38W CONTINUING ALONG 25N44W 21N55W. GALE FORCE WINDS ARE BOTH EAST AND WEST OF THE FRONT NORTH OF 28N. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE UP TO 250 NM EAST OF THE FRONT NORTH OF 26N. THE REMAINDER OF THE EAST ATLC IS COVERED BY SURFACE RIDGING AROUND A 1026 MB HIGH NEAR 38N18W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE ALONG 23W. THE GALE FORCE WINDS ARE EXPECTED TO DROP BELOW GALE FORCE WITHIN THE NEXT 12 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON