000 AXNT20 KNHC 201740 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST WED FEB 20 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1645 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA ENTERING THE TROPICAL ATLC ALONG THE COAST OF SIERRA LEONE AT 8N13W TO 4N19W. THE ITCZ BEGINS AT 4N19W AND CONTINUES TO THE EQUATOR AT 40W TO 1S47W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE AXIS BETWEEN 20W-35W...AND WITHIN 130 NM OF THE AXIS BETWEEN 41W-47W. ...DISCUSSION... GULF OF MEXICO... A WEAK FRONTAL BOUNDARY CONTINUES TO SKIM THE EASTERN GULF WITH A COLD FRONT EXTENDING FROM 27N80W TO 26N86W WHERE IT BECOMES A DISSIPATING STATIONARY BOUNDARY TO 27N91W AND A FORMING WARM FRONT TO THE TEXAS COAST AT 28N97W...AS OF 1500 UTC. ONLY A FEW POSSIBLE ISOLATED SHOWERS ARE NEAR THE AXIS. THE FRONT HAS LOST MOST OF ITS UPPER LEVEL SUPPORT AS THE UPPER TROUGH HAS SHIFTED EAST OF THE AREA WITH UPPER LEVEL RIDGING BUILDING OVER THE AREA. DRY AIR ALOFT IS ALSO PRESENT OVER A GOOD PORTION OF THE BASIN. SURFACE RIDGING IS TO THE NORTH OF THE FRONT COVERING MUCH OF THE EASTERN CONUS. THIS PATTERN IS PROVIDING MAINLY EASTERLY FLOW ACROSS THE AREA EXCEPT IMMEDIATELY NEAR THE COLD FRONT. WIND SPEEDS ARE LIGHTER ACROSS THE SOUTHEAST CORNER INCREASING IN SPEED TO 20-25 KT ACROSS THE NW CORNER. THE FRONTAL BOUNDARY IS EXPECTED TO SPLIT WITH THE COLD FRONT PUSHING EAST OF THE BASIN WHILE THE FORMING WARM FRONT LIFTS NORTH AND JOINS THE NEXT FRONTAL SYSTEM WHICH WILL REACH THE NW GULF EARLY FRIDAY. CARIBBEAN SEA... MOSTLY FAIR CONDITIONS ARE ACROSS THE CARIBBEAN TODAY DUE TO DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE OVER THE WESTERN CARIBBEAN AND A WEAK INVERTED UPPER TROUGH OVER THE EASTERN CARIBBEAN. STRONG SUBSIDENCE IS ALSO NOTED OVER THE SW CARIBBEAN AND NORTH OF VENEZUELA. A FEW ISOLATED SHOWERS ARE EMBEDDED WITHIN TRADEWIND FLOW OF 15-20 KT. STRONGER WINDS UP TO 30 KT ARE ALSO NORTH OF THE COLOMBIAN COAST. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... A BROAD UPPER TROUGH COVERS THE WEST ATLC SUPPORTING A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N71W TO 27N80W AND CONTINUES INTO THE GULF OF MEXICO. ISOLATED SHOWERS ARE IMMEDIATELY ALONG THE AXIS WITH AN AREA OF SHOWERS EAST OF THE AXIS FROM 26N-30N BETWEEN 65W-70W. THE REMAINDER OF THE WEST ATLC AND INTO THE CENTRAL ATLC IS DOMINATED BY SURFACE RIDGING AROUND A 1026 MG HIGH NEAR 31N54W. THE RIDGE IS SUPPORTED BY BROAD UPPER RIDGING WITH AXIS NEAR 55W. FARTHER EAST...A LARGE UPPER LEVEL LOW COVERING THE NORTH ATLC SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N28W CONTINUING AROUND THE RIDGE IN THE CENTRAL ATLC ALONG 28N40W 26N54W. ISOLATED SHOWERS ARE IMMEDIATELY ALONG THE AXIS. UPPER LEVEL RIDGING COVERS THE TROPICAL EAST ATLC ALONG 22W SUPPORTING WEAK SURFACE RIDGING ACROSS THIS PORTION OF THE BASIN. BOTH FRONTAL BOUNDARIES IN THE ATLC BASIN ARE EXPECTED TO MOVE EASTWARD OVER THE NEXT FEW DAYS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON