000 AXNT20 KNHC 202350 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT APR 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 6N11W TO 3N16W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 2N22W 3N32W 3N46W TO INLAND OVER SOUTH AMERICA NEAR 2N51W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 3N TO THE EQUATOR BETWEEN 5W-24W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER TROUGH COVERS MOST OF THE GULF AND THE E CONUS TO THE EASTERN SEABOARD SUPPORTING A COLD FRONT THAT AT 20/2100 UTC ENTERS THE GULF OVER THE FLORIDA PENINSULA BETWEEN BOCA RATON AND NAPLES TO 24N86W WHERE IT PULLS UP STATIONARY AS IT CONTINUES TO INLAND OVER THE YUCATAN PENINSULA NEAR MERIDA. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 240 NM N AND W OF THE FRONT. A SURFACE RIDGE IS BUILDING IN BEHIND THE FRONT ANCHORED BY A 1028 MB HIGH OVER THE GREAT LAKES. COLD FRONT WILL STALL AND WEAKEN TONIGHT THEN SLOWLY DISSIPATE THROUGH MON. ANOTHER COLD FRONT IS EXPECTED TO MOVE INTO THE NW GULF EARLY WED. CARIBBEAN SEA... AN UPPER RIDGE EXTENDS FROM THE E PACIFIC REGION ACROSS CENTRAL AMERICA INTO THE CARIBBEAN OVER THE GULF OF HONDURAS E TO CENTRAL CUBA. AN UPPER LOW IS N OF PUERTO RICO EXTENDING AN UPPER TROUGH INTO THE CARIBBEAN NEAR THE MONA PASSAGE THEN EXTENDS SW TO COSTA RICA/NICARAGUA. THE TRADE WINDS ARE ENHANCING SCATTERED SHOWERS GENERATED BY THE UPPER TROUGH OVER THE NE CARIBBEAN N OF 15N E OF 70W INCLUDING PUERTO RICO...THE VIRGIN AND LEEWARD ISLANDS. GUADELOUPE REPORTED EARLIER THIS MORNING OVER 3 INCHES OF RAIN IN THE PAST 24 HOURS. A SECOND UPPER RIDGE ANCHORED IN THE TROPICAL ATLC CLIPS THE SE CARIBBEAN. AFTERNOON THUNDERSTORMS ARE DEVELOPING INLAND OVER CUBA...W JAMAICA...AND HISPANIOLA. THE MONSOON TROUGH EXTENDS BETWEEN COLOMBIA AND COSTA RICA ALONG 9W/10W GENERATING SCATTERED SHOWERS S OF 11N W OF 80W. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN WITH MOSTLY CLEAR SKIES THIS EVENING. SURFACE RIDGE OVER THE W AND CENTRAL ATLC WILL MAINTAIN MODERATE TO FRESH TRADE WINDS ACROSS THE CARIBBEAN TONIGHT. WINDS AND SEAS WILL GRADUALLY DIMINISH SUN THROUGH WED. ATLANTIC OCEAN... THE UPPER TROUGH OVER THE E CONUS AND GULF OF MEXICO IS DRAPING A COLD FRONT INTO THE W ATLC AT 20/2100 UTC NEAR 32N74W ALONG 28N78W THEN ACROSS FLORIDA INTO THE GULF OF MEXICO NEAR BOCA RATON. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 210 NM W OF THE FRONT. THE UPPER RIDGE OVER THE CARIBBEAN EXTENDS INTO THE W ATLC ACROSS CENTRAL CUBA AND THE CENTRAL BAHAMAS TO BEYOND 32N70W. THIS UPPER RIDGE IS PROVIDING DIFFLUNCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120 NM E OF THE FRONT. AN UPPER LOW IS N OF PUERTO RICO NEAR 21N66W EXTENDING AN UPPER TROUGH INTO THE CARIBBEAN NEAR THE MONA PASSAGE AND GENERATING SCATTERED SHOWERS FROM 15N-20N BETWEEN 60W-69W INCLUDING PUERTO RICO...THE VIRGIN AND LEEWARD ISLANDS. THE REMAINDER OF THE CENTRAL ATLC IS DOMINATED BY A BROAD UPPER RIDGE. A SURFACE RIDGE DOMINATES THE W AND CENTRAL ATLC W OF 45W TO THE COLD FRONT ANCHORED WELL N OF THE DISCUSSION AREA. AN UPPER TROUGH IS IN THE E/CENTRAL ATLC IS N OF 20N BETWEEN 30W-48W SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 32N36W ALONG 28N40W TO 26N45W AND A SURFACE TROUGH THAT EXTENDS FROM 30N36W TO 24N44W. SCATTERED SHOWERS DOT THE AREA N OF 25N BETWEEN 33W-43W. A WEAK 1011 MB SURFACE LOW IS JUST W OF THE CANARY ISLANDS NEAR 29N19W WITH A SURFACE TROUGH EXTENDING E-SE TO 27N14W. W ATLC COLD FRONT WILL BECOME STATIONARY TONIGHT AND SLOWLY WEAKEN INTO A TROUGH. THE TROUGH WILL THEN DRIFT NORTHWARD SUN AND MON. HIGH PRESSURE WILL BUILD S ALONG THE SE U.S. COAST AND NE FLORIDA COAST MON AND TUE AS THE TROUGH MOVES NE AWAY FROM THE AREA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW