000 AXNT20 KNHC 201731 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI APR 20 2012 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 1715 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS INLAND ACROSS THE TROPICAL REGIONS OF WEST AFRICA INTO THE ATLC BASIN ACROSS THE COAST OF SIERRA LEONE NEAR 7N12W TO 5N14W...WHERE THE ITCZ AXIS CONTINUES ALONG THE EQUATOR NEAR 24W TO THE COAST OF BRAZIL NEAR 3S41W. CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION ARE WITHIN 170 NM ON EITHER SIDE OF THE MONSOON TROUGH AND ITCZ AXIS E OF 30W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL SHORTWAVE MOVES ACROSS THE FAR SE CONUS ON WATER VAPOR IMAGERY. THE BACK SE QUADRANT OF THIS FEATURE SUPPORTS A WEAK NEARLY STATIONARY SURFACE TROUGH ANALYZED FROM 27N85W TO 23N88W. VISIBLE SATELLITE IMAGERY INDICATES SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS WITHIN 70 NM ON EITHER SIDE OF THE BOUNDARY. THIS TROUGH IS FORECAST TO LIFT NORTH INCREASING CONVECTION OVER THE NE BASIN. WESTERLY ZONAL FLOW ALOFT WITH STRONG SUBSIDENCE AND DRY STABLE AIR ARE DOMINATING ELSEWHERE ACROSS THE DISCUSSION AREA THIS AFTERNOON. A LOW PRESSURE SYSTEM CURRENTLY OVER ERN TEXAS IS MOVING SE INTO THE NRN GULF. A COLD FRONT ASSOCIATED WITH THE LOW WILL ENTER THE NW GULF TONIGHT WITH GUSTY NORTHERLY WINDS UP TO NEAR 25 KTS BEHIND IT. CARIBBEAN SEA... THE MONSOON TROUGH EXTENDS ACROSS THE ERN TROPICAL PACIFIC BASIN INTO INTO THE FAR SW CARIBBEAN BASIN ALONG WRN PANAMA TO NRN COLOMBIA ALONG 9N82W TO NEAR 10N75W. THIS FEATURE IS GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS 80 NM ON EITHER SIDE OF ITS AXIS. THIS AREA OF CONVECTION IS EXPECTED TO CONTINUE OVER THE NEXT 24 HOURS. A SLOW MOVING SURFACE TROUGH IS ANALYZED OVER THE LESSER ANTILLES 18N58W TO 10N64W GENERATING SCATTERED HEAVY SHOWERS AFFECTING THESE GROUP OF ISLANDS S OF BARBUDA E OF 64W. OTHERWISE...RELATIVELY DRY AIR AND SUBSIDENCE ALOFT COVERS A GREAT PORTION OF THE CARIBBEAN BASIN. CONVERGING TRADE WIND FLOW ALONG WITH LOW LEVEL MOISTURE IS GENERATING SCATTERED LOW-TOP SHOWERS ELSEWHERE ACROSS THE DISCUSSION AREA. SHORT RANGE COMPUTER MODELS SUGGEST SIGNIFICANT MOISTURE AND CONVECTION WILL REMAIN OVER THE FAR ERN CARIBBEAN INCLUDING THE LESSER ANTILLES ISLANDS DURING THE NEXT 24 HOURS. ATLANTIC OCEAN... A SURFACE TROUGH EXTENDS S FROM 31N79W TO 28N80W ASSOCIATED TO A FRONTAL BOUNDARY ANALYZED OFF THE COAST OF THE CAROLINAS AND GEORGIA TO NRN FLORIDA. THIS FRONTAL SYSTEM IS GENERATING AN AREA OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS N OF 27N W OF 75W. OTHERWISE...A WEAK 1019 MB HIGH NEAR 30N67W MAINTAINING FAIR WEATHER CONDITIONS W OF 50W. A WEAKENING COLD FRONT ENTERS THE CENTRAL REGION ALONG 30N45W TO NEAR 25N46W BECOMING A WEAK SURFACE TROUGH TO NEAR 22N50W. THIS FRONTAL BOUNDARY IS RELATED TO A DEEP OCCLUDED LOW PRESSURE SYSTEM N OF THE DISCUSSION AREA CENTERED NEAR 37N52W. SCATTERED WEAK CONVECTION IS WITHIN 50-100 NM ON EITHER SIDE OF THE COLD FRONT/TROUGH AXIS. A DISSIPATING 1009 MB LOW IS TO THE WEST OF THIS FRONTAL BOUNDARY NEAR 29N50W WITH NO SIGNIFICANT CONVECTION. OTHERWISE...A BROAD SURFACE RIDGE ANCHORED BY A 1026 MB HIGH SW OF THE AZORES OVERTAKES THE REMAINDER OF THE ATLC WITH FAIR WEATHER CONDITIONS E OF 40W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA