000 AXNT20 KNHC 192336 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN MAY 19 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. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 8N30W EQ31W MOVING WEST AT 10-15 KT. THE WAVE SHOWS A GOOD SIGNAL IN 700 MB STREAMLINES AND SATELLITE DERIVED WINDS. CURRENTLY NO DEEP CONVECTION IS NEAR THE WAVE AXIS. TROPICAL WAVE EXTENDS FROM 11N60W TO 5N61W MOVING W AT 15 KT. THE WAVE IS PRIMARILY OVER SOUTH AMERICA...BUT THE MOISTURE SIGNAL IN TOTAL PRECIPITABLE WATER IMAGERY EXTENDS UP TO 15N. SCATTERED MODERATE/ISOLATE STRONG CONVECTION REMAINS OVER LAND WITHIN 200 NM TO EITHER SIDE. MOISTURE ASSOCIATED WITH THE WAVE HAS ALMOST REACHED THE WINDWARD ISLANDS AND WILL LIKELY PRODUCE PRECIPITATION OVER THE ISLANDS DURING THE NEXT DAY OR SO. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF SIERRA LEONE NEAR 8N13W TO 6N14W 4N16W. THE ITCZ BEGINS AT 4N16W AND CONTINUES ALONG 3N24W 5N28W WHERE IT BREAKS AROUND THE TROPICAL WAVE AND PICKS UP ALONG EQ32W 1S48W. A LARGE AREA OF NUMEROUS STRONG CONVECTION IS MOVING OFF THE AFRICAN COAST FROM 3N-12N BETWEEN 12W-17W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 2N-6N BETWEEN 21-26W. ...DISCUSSION... GULF OF MEXICO... MOSTLY FAIR WEATHER SPREADS ACROSS THE GULF OF MEXICO ALONG WITH BROAD SURFACE RIDGING EXTENDING FROM THE NW ATLC. SOME UPPER LEVEL CLOUD COVER IS MOVING EASTWARD ACROSS THE BASIN CURRENTLY OVER THE EASTERN HALF ASSOCIATED WITH A SHORTWAVE UPPER TROUGH ALONG 92W THAT EXTENDS SOUTHWARD TO 25N. BROAD UPPER RIDGING COVERS THE REMAINDER OF THE BASIN. MOSTLY SOUTHEAST FLOW IS PRESENT AT THE SURFACE RANGING FROM 10 KT IN THE EASTERN PORTIONS TO 15-20 OVER THE WESTERN GULF. RADAR IMAGERY INDICATES SEVERAL CLUSTERS OF STRONG LATE AFTERNOON SHOWERS AND THUNDERSTORMS STILL CONTINUE OVER PORTIONS OF THE FLORIDA PENINSULA MAINLY FOCUSED ON THE SW CORNER AND NORTH CENTRAL PARTS. A FEW STORMS HAVE ALSO MOVED OFF CUBA INTO THE SE GULF. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24 HOURS. CARIBBEAN SEA... DRY AND STABLE AIR COVERS THE MAJORITY OF THE CARIBBEAN AROUND A BROAD UPPER LEVEL TROUGH COVERING THE BASIN. THE DRY AIR IS HELPING MAINTAIN GENERALLY FAIR WEATHER ACROSS THE AREA. HOWEVER...AFTERNOON SHOWERS AND THUNDERSTORMS POPPED UP AND CONTINUE ACROSS MANY OF THE NORTHERN CARIBBEAN ISLANDS INCLUDING CUBA...JAMAICA...HISPANIOLA...AND PUERTO RICO. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO IN THE FAR SW CORNER AND OVER COSTA RICA AND PANAMA ASSOCIATED WITH THE MONSOON TROUGH THAT EXTENDS FROM THE E PACIFIC THROUGH BOTH COUNTRIES CONTINUING INTO COLOMBIA. TRADEWIND FLOW OF 15-20 KT DOMINATES THROUGHOUT.A FEW ISOLATED SHOWERS ARE MOVING WITHIN THE TRADEWIND FLOW ACROSS THE LESSER ANTILLES. LITTLE CHANGE IS EXPECTED EXCEPT FOR AN INCREASE IN MOISTURE ACROSS THE WINDWARD ISLANDS AS A TROPICAL WAVE JUST EAST OF THE ISLANDS CONTINUES TO MOVE WESTWARD. THERE WILL BE AN INCREASED CHANCE OF HEAVIER RAIN AS THE WAVE PASSES. HISPANIOLA... CURRENTLY AFTERNOON SHOWERS AND THUNDERSTORMS CONTINUE TO IMPACT THE ISLAND OF HISPANIOLA MAINLY CONCENTRATED IN THE CENTRAL PORTION. AS THE SUN GOES DOWN THIS ACTIVITY SHOULD DIE DOWN. MODEL GUIDANCE INDICATES A SIMILAR PATTERN WILL PERSIST OVER THE NEXT COUPLE OF DAYS WITH THE MOST LIKELY PRECIPITATION TO BE DURING THE AFTERNOON AND EARLY EVENING HOURS ACROSS THE ISLAND WHEN PEAK DAYTIME HEATING AND INSTABILITY OCCUR. ANY AREAS THAT RECEIVE MEASURABLE AMOUNTS OF RAINFALL WILL LIKELY BE PRONE TO LOCALIZED FLOODING. ATLANTIC OCEAN... A COLD FRONT HAS SUNK SOUTH INTO THE DISCUSSION AREA ALONG 31N60W 29N67W 31N73W. ISOLATED SHOWERS ARE ALONG THE AXIS. A FEW ISOLATED SHOWERS ARE ALSO NOTED OVER THE BAHAMAS. THE FRONT WRAPS AROUND A SURFACE RIDGE CENTERED WELL TO THE NORTH. THE FRONT IS SUPPORTED BY AN UPPER LEVEL TROUGH ALONG 57W THAT EXTENDS NORTH OF 30N. BROAD UPPER TROUGHING CONTINUES INTO THE SOUTHWEST NORTH ATLC AS WELL. IN THE CENTRAL ATLC...A PAIR OF WEAK SURFACE TROUGHS ARE PRESENT. THE FIRST IS ALONG 30N57W TO 24N63W. IT ORIGINATED FROM A NOW DISSIPATED FRONTAL BOUNDARY. POSSIBLE ISOLATED SHOWERS ARE ALONG IT. THE SECOND SURFACE TROUGH IS ALONG 29N48W 24N44W. ISOLATED SHOWERS ARE ALONG THE AXIS. AN AREA OF ISOLATED SHOWERS IS ALSO EAST OF THE LESSER ANTILLES FROM 10N-18N BETWEEN 53W-61W. THIS ACTIVITY IS ASSOCIATED WITH ENHANCED MOISTURE NEAR A TROPICAL WAVE TO THE SOUTH. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS DOMINATED BY BROAD SURFACE RIDGING AROUND A 1033 MB HIGH NEAR 42N30W. ALOFT...BROAD UPPER RIDGING COVERS THE TROPICAL ATLC WITH AN UPPER LEVEL LOW TO THE NORTH NEAR 31N33W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON