000 AXNT20 KNHC 211804 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI JUN 21 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 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE AXIS IS OVER EASTERN CUBA ALONG 23N74W TO 14N77W AND MOVING W-NW AT 10 KT. TOTAL PRECIPITABLE WATER AND WATER VAPOR IMAGERY INDICATE VERY DRY AIR IN THE WAVE ENVIRONMENT AT LOWER AND MIDDLE LEVELS. THIS IS INHIBITING CONVECTIVE ACTIVITY OVER CUBA AND ADJACENT WATERS. TROPICAL WAVE IS EMBEDDED IN THE ITCZ AXIS ALONG 15N44W TO 06N43W MOVING WEST AT 10 KT. METEOSAT-9 SAL TRACKING IMAGERY CONTINUE TO SHOW VERY DRY AIR SPREADING OVER THE WAVE ENVIRONMENT WHICH IS SUPPRESSING THE CONVECTION. TROPICAL WAVE AXIS EXTENDS FROM 16N27W TO 07N30W MOVING WEST AT 15-20 KT. METEOSAT-9 PSEUDO NATURAL COLOR AND SAL TRACKING IMAGERY SHOW THAT A NEW SAL OUTBREAK IS SPREADING DUST AND DRY AIR OVER THE WAVE ENVIRONMENT WHICH IS HINDERING CONVECTIVE ACTIVITY. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL AFRICA NEAR 13N16W TO 09N21W. THE ITCZ CONTINUES FROM 09N21W TO 06N30W 09N38W TO 09N43W. IT RESUMES WEST OF A TROPICAL WAVE NEAR 08N45W TO 06N57W. ISOLATED MODERATE CONVECTION IS FROM 02N-08N BETWEEN 13W- 35W. ...DISCUSSION... THE GULF OF MEXICO... RETURN FLOW CONTINUE TO DOMINATE ACROSS MOST OF THE GULF WITH WINDS RANGING FROM 10-15 KT. THIS WINDS ARE BEING SUPPORTED BY A 1019 MB HIGH IN THE NW GULF NEAR 27N91W. A PREVIOUS STATIONARY FRONT ACROSS THE N-CENTRAL AND NE GULF HAS TRANSITIONED TO A COLD FRONT THAT EXTENDS FROM 28N82W TO 28N86W TO 28N91W. RADAR IMAGERY SHOW ISOLATED SHOWERS AND THUNDERSTORMS N OF 26N EAST OF 93W ASSOCIATED TO THIS FRONT. THE REMNANTS OF TROPICAL STORM BARRY CONTINUE TO GENERATE RAINSHOWERS AND ISOLATED THUNDERSTORMS IN THE SW GULF S OF 24N W OF 94W. OTHERWISE...IN THE REMAINDER OF THE GULF FAIR WEATHER IS PRESENT ASSISTED BY A DRY STABLE ENVIRONMENT IN THE LOWER AND MIDDLE LEVELS. THE HIGH PRESSURE OVER THE NW GULF IS EXPECTED TO DISSIPATE EARLY ON SATURDAY WHILE THE FRONTAL BOUNDARY OVER THE NE GULF MOVES N OF THE AREA. A TROPICAL WAVE CURRENTLY OVER EASTERN CUBA IS EXPECTED TO ENTER THE SE GULF BY EARLY AFTERNOON SATURDAY. RETURN FLOW IS EXPECTED TO CONTINUE DURING THE NEXT 48 HOURS. THE CARIBBEAN SEA... THE MAIN FEATURE IN THE CARIBBEAN IS A TROPICAL WAVE WITH AXIS EXTENDING ACROSS EASTERN CUBA ALONG 23N74W TO 14N77W. TOTAL PRECIPITABLE WATER AND WATER VAPOR IMAGERY INDICATE VERY DRY AIR IN THE WAVE ENVIRONMENT AT LOWER AND MIDDLE LEVELS WHICH IS INHIBITING CONVECTIVE ACTIVITY OVER THE ISLAND AND ADJACENT WATERS. SCATTERED MODERATE CONVECTION AND THUNDERSTORMS ARE OVER THE SOUTHERN CARIBBEAN WITHIN 160 NM OF THE NICARAGUA...COSTA RICA AND PANAMA COASTLINES. THIS CONVECTION IS ASSOCIATED WITH CONVECTIVE ACTIVITY OF THE MONSOON TROUGH WHICH AXIS CROSSES COSTA RICA AND PANAMA. ISOLATED SHOWERS ARE OCCURRING EAST OF A LINE FROM 17N67W TO 12N73W BEING ENHANCED BY UPPER LEVEL DIFFLUENCE FROM A TROUGH CENTERED IN THE BASIN AND THE WESTERN PERIPHERY OF A BROAD RIDGE OVER THE CENTRAL ATLC. OTHERWISE...THE REMAINDER OF THE BASIN IS EXPERIENCING FAIR WEATHER DUE IN PART TO THE PRESENCE OF DRY STABLE AIR IN THE LOWER AND MIDDLE LEVELS. SOME OF THE LESSER ANTILLES ARE REPORTING WIDESPREAD DUST WHILE OTHERS ARE REPORTING SHOWERS AND ISOLATED THUNDERSTORMS. IN TERMS OF WINDS...TRADEWINDS OF 15-20 KT ABOUND ACROSS THE BASIN. THE TROPICAL WAVE WILL CONTINUE A W-NW TRACK AND WILL EXIT THE ISLAND OF CUBA BY EARLY AFTERNOON SATURDAY TO ENTER THE SE GULF. ANOTHER WAVE IS EXPECTED TO ENTER THE EASTERN CARIBBEAN BY EARLY MORNING SUNDAY. HISPANIOLA... DRY AIR IN THE LOWER LEVELS AS WELL AS THE PRESENCE OF AN UPPER LEVEL LOW NW OF THE ISLAND IS KEEPING A CONVECTIVE FREE ENVIRONMENT. EXCEPT FOR AFTERNOON/EVENING SHOWERS ENHANCED BY SURFACE DAYTIME HEATING...FAIR WEATHER IS EXPECTED TO CONTINUE UNTIL EARLY SUNDAY. THE ENVIRONMENT WILL START TO BECOME UNSTABLE AS A TROPICAL WAVE WITH AXIS CURRENTLY NEAR 45W MOVES ACROSS THE EASTERN CARIBBEAN. WEATHER CONDITIONS ARE EXPECTED TO DEGRADE SUNDAY MORNING AS THE WAVE CROSSES THE MONA PASSAGE INTO THE DOMINICAN REPUBLIC. THE ATLANTIC OCEAN... AS OF 1500 UTC...A PREVIOUS STATIONARY FRONT HAS TRANSITIONED INTO A COLD FRONT THAT EXTENDS FROM 30N79W TO 29N81W...THEN ACROSS NORTHERN FLORIDA INTO THE N CENTRAL GULF. RADAR IMAGERY SHOW ISOLATED SHOWERS AND THUNDERSTORMS N OF 29N W OF 78W. OTHERWISE...BROAD SURFACE RIDGING EXTENDING FROM THE AZORES HIGH CONTINUE TO SPREAD ACROSS THE REMAINDER OF THE BASIN N OF 19N. FAIR WEATHER IS PRESENT IN THIS WIDE REGION OF THE ATLC BEING SUPPORTED BY THE PRESENCE OF MIDDLE TO LOWER LEVELS DRY AIR. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ RAMOS