000 AXNT20 KNHC 231047 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE JUL 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1022 UTC. ...SPECIAL FEATURES... A TROPICAL WAVE ASSOCIATED WITH A 1010 MB SURFACE LOW HAS ITS AXIS JUST E OF THE CAPE VERDE ISLANDS EXTENDING FROM 15N22W TO 07N23W AND MOVING W NEAR 5 KT. THIS SYSTEM IS EMBEDDED IN A HIGH MOIST ENVIRONMENT AT THE LOWER AND MIDDLE LEVELS WHICH COMBINED WITH UPPER LEVEL DIFFLUENCE IS SUPPORTING SCATTERED MODERATE CONVECTION FROM 09N-13N BETWEEN 21W-27W. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BECOME MORE FAVORABLE FOR TROPICAL CYCLONE DEVELOPMENT. CURRENTLY...THERE IS A MEDIUM CHANCE FOR THIS SYSTEM TO BECOME A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... A TROPICAL WAVE IS MOVING ACROSS THE DOMINICAN REPUBLIC WITH A TILTED AXIS EXTENDING ALONG 21N67W TO 15N72W AND MOVING NEAR 15 KT. THE WAVE IS EMBEDDED IN A MODERATE MOIST ENVIRONMENT AND AT THE MOMENT ONLY ISOLATED SHOWERS AND TSTMS ARE WITHIN 80 NM EITHER SIDE OF THE WAVE AXIS N OF 19N. HOWEVER...MIDDLE LEVEL DIFFLUENT FLOW MAY ASSIST IN DEVELOPING CONVECTION AS THE WAVE CONTINUE A W-NW TRACK ACROSS THE HISPANIOLA TODAY. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 15N16W AND CONTINUES TO 14N20W. THE ITCZ AXIS EXTENDS W OF A TROPICAL WAVE NEAR 11N26W TO 06N39W 05N52W. BESIDES THE CONVECTION ALREADY DISCUSSED ASSOCIATED WITH THE TROPICAL WAVE...SCATTERED MODERATE CONVECTION IS FROM 07N-12N E OF 18W. ISOLATED RAINSHOWERS ARE WITHIN 100 NM S OF THE ITCZ AXIS BETWEEN 33W-38W. ...DISCUSSION... GULF OF MEXICO... SURFACE RIDGING DOMINATES THE GULF ANCHORED BY A 1020 MB HIGH NEAR 27N86W THAT IS PROVIDING RETURN FLOW IN THE RANGE OF 5-15 KT. EXCEPT FOR THE NE GULF N OF 28N...VERY DRY AIR AT THE LOWER AND MIDDLE LEVELS ACROSS THE BASIN IS SUPPORTING FAIR WEATHER. OVER THE NE GULF...A HIGH MOIST ENVIRONMENT AT THE LOWER AND MIDDLE LEVELS AS WELL AS UPPER LEVEL DIFFLUENCE ARE SUPPORTING A CLUSTER OF MODERATE CONVECTION N OF 28N E OF 86W. THE HIGH IS EXPECTED TO PERSIST OVER THE GULF WATERS WITHIN THE NEXT 48 HOURS. RAINSHOWERS OVER THE NE GULF ARE EXPECTED TO CONTINUE UNTIL VERY LATE ON TUESDAY BUT THE REST OF THE BASIN WILL ENJOY FAIR WEATHER AS DRY AIR CONTINUES TO BE ADVECTED FROM THE CARIBBEAN INTO THE GULF. THE CARIBBEAN SEA... A TROPICAL WAVE IS MOVING ACROSS THE DOMINICAN REPUBLIC THIS MORNING GENERATING ISOLATED SHOWERS/TSTMS AND ADVECTING MODERATE MOISTURE ACROSS THE HISPANIOLA. RAINSHOWERS MAY DEVELOPED OVER THE ISLAND AS THE DAY PROGRESSES ASSISTED BY MIDDLE LEVEL DIFFLUENT FLOW. A VERY MOIST ENVIRONMENT IN THE LOWER AND MIDDLE LEVELS IS OVER THE SOUTHERN CARIBBEAN S OF 17N W OF 78W. THIS MOIST ENVIRONMENT COMBINED WITH UPPER LEVEL DIFFLUENCE IS SUPPORTING SCATTERED MODERATE CONVECTION WITH ISOLATED TSTMS OVER NICARAGUA AND WITHIN 190 NM OFF ITS COASTLINE AS WELL AS WITHIN 110 NM OFF THE COAST OF HONDURAS. SIMILAR CONVECTION IS S OF 10N INCLUDING PANAMA AND THE COASTAL WATERS OF COSTA RICA BEING ASSOCIATED WITH THE MONSOON TROUGH AXIS. ISOLATED RAINSHOWERS ARE WITHIN 100 NM OF THE SOUTHERN COAST OF CUBA BETWEEN 79W-82W. OVER THE REMAINDER BASIN...DRY AIR IN THE LOWER AND MIDDLE LEVELS IS SUPPORTING FAIR WEATHER. OTHERWISE...TRADEWINDS UP TO 25 KT PREVAIL OVER THE CENTRAL- SOUTHERN CARIBBEAN WITH LIGHTER WINDS UP TO 15 KT ELSEWHERE. THE TROPICAL WAVE WILL MOVE OFF THE COAST OF HAITI THIS AFTERNOON AND MOVE TO EASTERN CUBA WHERE INTERACTION WITH THE TERRAIN AND VERY DRY AIR MAY ACT TO VANISH THIS WAVE. HISPANIOLA... A TROPICAL WAVE IS MOVING ACROSS THE DOMINICAN REPUBLIC THIS MORNING WITH AXIS EXTENDING FROM 21N67W TO 15N72W. THE WAVE IS GENERATING ISOLATED SHOWERS AND IS ADVECTING MODERATE MOISTURE ACROSS THE ISLAND. RAINSHOWERS MAY DEVELOPED OVER THE ISLAND AS THE DAY PROGRESSES ASSISTED BY MIDDLE LEVEL DIFFLUENCE. WEATHER IMPROVES THIS AFTERNOON FOR THE DOMINICAN REPUBLIC AS A MASS OF DRY AIR ENTERS THIS PORTION OF THE ISLAND. THE DRY AIR MASS WILL CONTINUE TO MOVE WESTWARD AND WILL MOVE OFF THE COAST OF HAITI VERY EARLY ON WEDNESDAY. AFTERNOON/EARLY EVENING SHOWERS ARE EXPECTED ON WEDNESDAY SUPPORTED BY A FAVORABLE UPPER LEVEL PATTERN. THE ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL LOW CENTERED NEAR 30N51W IS SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS N OF 26N BETWEEN 49W-59W. A SURFACE TROUGH EXTENDS FROM A 1018 MB LOW NEAR 30N32W TO 27N36W 26N41W...NO CONVECTION IS ASSOCIATED WITH IT AT THE TIME. OTHERWISE...SURFACE RIDGING IS ACROSS THE REMAINDER BASIN ANCHORED BY A 1022 MB HIGH NEAR 36N43W. BESIDES THE AREAS FORMERLY DISCUSSED...FAIR WEATHER IS ACROSS THE REMAINDER ATLC SUPPORTED BY DRY AIR AT THE LOWER AND MIDDLE LEVELS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ RAMOS