000 AXNT20 KNHC 020002 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON JUL 01 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 2345 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 15N27W TO 08N28W MOVING WEST AT 15 KT. THE WAVE CORRESPONDS WITH A 700 MB TROUGH AXIS. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE POSSIBLY DUE TO SAL DRY AIR WITHIN THE WAVE ENVIRONMENT AS DEPICTED IN METEOSAT- 9 SAL TRACKING PRODUCT. TROPICAL WAVE IS ALONG 18N46W TO 08N46W MOVING WEST AT 20 KT. THIS WAVE IS EMBEDDED IN A VERY DRY ENVIRONMENT AS DEPICTED IN TOTAL PRECIPITABLE WATER IMAGERY AS WELL AS THE METEOSAT-9 SAL TRACKING PRODUCT. THE PRESENCE OF DRY SAL AIR IS INHIBITING ANY FORM OF CONVECTION. TROPICAL WAVE IS ALONG 22N70W TO 12N74W MOVING WEST NEAR 10 KT. THE WAVE AXIS IS MOSTLY EMBEDDED WITHIN A MODERATE MOIST ENVIRONMENT AT THE LOWER LEVELS...EXCEPT N OF 16N BETWEEN 71W- 75W WHERE MAXIMUM MOISTURE IS DEPICTED IN TOTAL PRECIPITABLE WATER IMAGERY. BESIDES MOISTURE AVAILABILITY AT LOWER AND MIDDLE LEVELS...AN UPPER LEVEL TROUGH OVER THE WINDWARD PASSAGE IS ENHANCING NUMEROUS MODERATE CONVECTION OVER LA HISPANIOLA AND THUNDERSTORMS OVER HAITI. THIS ACTIVITY EXTENDS WITHIN 150 NM SOUTH OF LA HISPANIOLA. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR 13N16W TO 10N21W. THE ITCZ AXIS BEGINS NEAR 10N21W TO 09N27W AND THEN CONTINUES WEST OF A TROPICAL WAVE ALONG 09N29W 06N42W 01N49W. SCATTERED MODERATE CONVECTION IS WITHIN 165 NM SOUTH OF THE AXIS EAST OF 21W. ISOLATED MODERATE CONVECTION IS WITHIN 140 NM EITHER SIDE OF THE AXIS BETWEEN 29W-45W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH CONTINUES TO SIT OVER THE GULF OF MEXICO WITH AXIS EXTENDING ALONG 87W. THE UPPER TROUGH SUPPORTS A STATIONARY FRONT ACROSS THE NORTHERN GULF ALONG 30N86W 28N90W 28N95W 27N97W. A PRE-FRONTAL SURFACE TROUGH IS OUT AHEAD OF THE FRONT ALONG 30N83W 24N88W. WIDESPREAD SHOWERS/ISOLATED THUNDERSTORMS COVER MUCH OF THE AREA EAST OF THE SURFACE TROUGH AND UP TO 60 NM WEST OF THE TROUGH AXIS. SHOWERS/THUNDERSTORMS CONTINUE OVER MUCH OF FLORIDA. THIS CONVECTION IS MAINLY IN THE AREA OF STRONGEST DIFFLUENCE ALOFT. THE REMAINDER OF THE BASIN IS FAIRLY CLEAR AT THIS TIME DUE TO DRY AIR ALOFT SINKING AROUND THE WEST SIDE OF THE UPPER TROUGH. A WEAK 1013 MB HIGH IS OVER THE SW GULF NEAR 23N95W PROVIDING LIGHT ANTICYCLONIC WIND FLOW IN THIS PART OF THE BASIN. WINDS INCREASE UP TO 20 KT OVER THE EASTERN GULF. OTHERWISE...THE STATIONARY FRONT IS EXPECTED TO DISSIPATE EARLY ON TUESDAY AS SOUTHERLY FLOW BUILDS OVER THE EASTERN GULF. THE HIGH PRESSURE IS EXPECTED TO DISSIPATE LATE TUESDAY. MOISTURE ADVECTION FROM THE CARIBBEAN BY SOUTHERLY FLOW AND PERSISTENCE OF THE UPPER LEVEL TROUGH ACROSS THE BASIN MAY CONTINUE ENHANCING SHOWERS WITHIN THE NEXT 48 HOURS OVER THE EASTERN GULF. CARIBBEAN SEA... AS OF 2100 UTC...THE SURFACE TROUGH THAT WAS OVER THE WEST CARIBBEAN HAS MOVED INTO THE YUCATAN PENINSULA WHERE IS GENERATING SHOWERS AND THUNDERSTORMS THAT EXTENDS WITHIN 100 NM OFF THE EAST COAST. A NARROW UPPER LEVEL RIDGE CENTERED OVER THE WESTERN CARIBBEAN AND THE UPPER TROUGH CENTERED NEAR THE WINDWARD PASSAGE IS PROVIDING STRONG DIFFLUENT FLOW ALOFT. THIS COMBINED WITH ABUNDANT LOW LEVEL MOISTURE IS ENHANCING SCATTERED MODERATE CONVECTION AND THUNDERSTORMS N OF 14N BETWEEN 75W- 82W...INCLUDING EASTERN CUBA AND JAMAICA. BROAD UPPER TROUGHING COVERS THE REMAINDER OF THE BASIN. THIS TROUGH CENTERED OVER THE WINDWARD PASSAGE IS ENHANCING NUMEROUS MODERATE CONVECTION OVER LA HISPANIOLA AND THUNDERSTORMS OVER HAITI. THIS CONVECTIVE ACTIVITY EXTENDS WITHIN 150 NM SOUTH OF LA HISPANIOLA. WIDESPREAD DUST IS BEING REPORTED ACROSS THE LESSER ANTILLES. OTHERWISE...TRADEWINDS UP TO 20 KT ABOUND ACROSS THE BASIN WITH THE MAXIMUM WINDS BEING IN THE CENTRAL CARIBBEAN DUE TO A TIGHTER PRESSURE GRADIENT. RAINSHOWERS AND THUNDERSTORMS ARE LIKELY TO PERSIST OVER THE WESTERN CARIBBEAN WITHIN 48 HOURS AS THE UPPER LEVEL SYNOPTIC PATTERN AND ABUNDANT MOISTURE CONTINUES. THE TROPICAL WAVE WILL MOVE OVER CUBA DURING TUESDAY AND THEN WILL DISSIPATE. HISPANIOLA... THE AXIS OF A TROPICAL WAVE IS MOVING ACROSS HAITI. THIS WAVE IS MOSTLY EMBEDDED WITHIN A MODERATE MOIST ENVIRONMENT AT THE LOWER LEVELS...EXCEPT N OF 16N BETWEEN 71W-75W WHERE MAXIMUM MOISTURE IS DEPICTED IN TOTAL PRECIPITABLE WATER IMAGERY. BESIDES MOISTURE AVAILABILITY AT LOWER AND MIDDLE LEVELS...AN UPPER LEVEL TROUGH OVER THE WINDWARD PASSAGE IS ENHANCING NUMEROUS MODERATE CONVECTION OVER LA HISPANIOLA AND THUNDERSTORMS OVER HAITI. THIS ACTIVITY EXTENDS WITHIN 150 NM SOUTH OF LA HISPANIOLA. MOISTURE ASSOCIATED WITH THE WAVE WILL LIKELY CONTINUE TO IMPACT HISPANIOLA UNTIL EARLY WEDNESDAY. ACTIVITY IS EXPECTED TO INCREASE DURING THE AFTERNOON HOURS AS THE DAY CONTINUES TO HEAT UP. ATLANTIC OCEAN... BROAD SURFACE RIDGING COVERS THE ATLC BASIN AROUND A SET OF HIGHS NORTH OF THE AREA OF DISCUSSION. SCATTERED SHOWERS/THUNDERSTORMS ARE OFF THE NE COAST OF FLORIDA NORTH OF 25N WEST OF 78W ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER THE GULF OF MEXICO. A FEW SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO NORTH OF HISPANIOLA FROM 18N-21N BETWEEN 68W-72W ASSOCIATED WITH A TROPICAL WAVE NEAR 73W. A WEAK SURFACE TROUGH IS ALONG 30N59W TO 27N56W WITH NO CONVECTION ASSOCIATED WITH IT AT THIS TIME. 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