000 AXNT20 KNHC 091803 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN AUG 09 2015 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 1745 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS RIGHT OFF THE WEST AFRICAN COAST WITH AXIS NEAR 17W...MOVING W AT APPROXIMATELY 5 KT. CIRA LAYER PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW MODERATE TO HIGH MOISTURE ASSOCIATED WITH THIS WAVE THAT ALONG WITH AN UPPER LEVEL DIFFLUENT WIND ENVIRONMENT SUPPORT A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION FROM 13N TO 17N BETWEEN 15W AND 19W AND ISOLATED MODERATE CONVECTION ELSEWHERE FROM 07N TO 20N E OF 23W. A TROPICAL WAVE IS IN THE CENTRAL ATLC WITH AXIS NEAR 37W...MOVING W AT APPROXIMATELY 10 KT. CIRA LAYER PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW MOSTLY A DRY WAVE ENVIRONMENT BEING CONFIRMED BY THE PRESENCE OF SAHARAN DRY AIR AND DUST IN METEOSAT ENHANCED IMAGERY. THESE CONDITIONS SUPPORT LACK OF CONVECTION AT THIS TIME. A TROPICAL WAVE IS NEARLY 500 NM E OF THE LESSER ANTILLES. ITS AXIS IS ALONG 52W AND IS MOVING AT APPROXIMATELY 5 KT. CIRA LAYER PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW A DRY WAVE ENVIRONMENT N OF 13 N AND MODERATE MOISTURE ENHANCING ISOLATED SHOWERS FROM 07N TO 12N BETWEEN 50W AND 55W. LACK OF CONVECTION N OF 13N IS DUE TO THE PRESENCE OF SAHARAN DRY AIR AND DUST AS DEPICTED BY METEOSAT ENHANCED IMAGERY. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF GUINEA NEAR 09N14W TO 07N30W TO 06N42W. THE ITCZ CONTINUES FROM 06N42W TO 05N50W TO GUYANA NEAR 05N59W. FOR INFORMATION ABOUT CONVECTION SEE THE TROPICAL WAVES SECTION. ...DISCUSSION... ...THE GULF OF MEXICO... A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM NEW ENGLAND S OVER THE W ATLC W OF 70W TO A BASE NEAR 29N IN THE SW N ATLC. THIS TROUGH ALOFT SUPPORTS A FRONTAL SYSTEM ANALYZED IN THE GULF AS A STATIONARY FRONT FROM 29N83W TO A 1013 MB LOW NEAR 29N85W TO SOUTHERN ALABAMA NEAR 31N87W. A SURFACE TROUGH EXTENDS FROM THE LOW SW TO 26N89W NW TO 27N92W. CIRA LAYER PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW MODERATE MOISTURE OVER THE NE GULF THAT ALONG WITH A DIVERGENT ENVIRONMENT IN THE MIDDLE LEVELS SUPPORT SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS FROM 25N TO 29N BETWEEN 84W AND 89W. GOES-R CONVECTIVE INITIATION PRODUCT INDICATES THE CONTINUATION OF ISOLATED TSTMS DURING THE NEXT TWO HOURS. SW OF THE SURFACE TROUGH TAIL...A 1016 MB HIGH IS NEAR 25N91W...WHICH IS FORECAST TO MOVE TO THE NW BASIN OVER THE NEXT 48 HOURS. CLEAR SKIES DOMINATE ELSEWHERE OVER THE GULF...BEING SUPPORTED BY DRY AIR SUBSIDENCE AND STRONG WIND SHEAR. WINDS ACROSS THE BASIN ARE VARIABLE RANGING FROM 5 TO 10 KT. ...THE CARIBBEAN SEA... EXCEPT FOR THE SW CARIBBEAN AND CUBA SOUTHERN ADJACENT WATERS... CIRA LAYER PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW A DRY ENVIRONMENT ACROSS THE CARIBBEAN WATERS...THUS RESULTING IN STABILITY AND FAIR WEATHER. OVER THE SW BASIN...A 1010 MB LOW IS OFF THE NW COAST OF COLOMBIA ENHANCING SCATTERED MODERATE CONVECTION S OF 12N. A BROAD UPPER LEVEL TROUGH EXTENDING FROM THE SW N ATLC SW TO A BASE S OF HISPANIOLA SUPPORTS ISOLATED SHOWERS AND TSTMS ALONG SOUTHERN CUBA AND COASTAL WATERS AS WELL AS ACROSS CENTRAL AND WESTERN HISPANIOLA. NE TO E WINDS OF 20 TO 25 KT ARE FROM 12N TO 15N BETWEEN 69W AND 76W WITH SEAS TO 8 FT. TRADES OF 15 KT ARE ACROSS THE REMAINDER BASIN. THE NEXT TROPICAL WAVE IS FORECAST TO ENTER THE E CARIBBEAN MONDAY MORNING. ...HISPANIOLA... PATCHES OF MODERATE MOISTURE CONTINUE OVER THE ISLAND AS INDICATED BY CIRA LAYER PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB. THIS SHALLOW MOISTURE ALONG WITH FORCING GENERATED BY AN UPPER TROUGH WITH EMBEDDED LOW JUST S OF THE ISLAND SUPPORT ISOLATED SHOWERS AND TSTMS MAINLY OVER CENTRAL AND WESTERN PORTIONS OF HISPANIOLA. SHOWERS ARE EXPECTED TO CONTINUE THROUGH TONIGHT. THE ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM NEW ENGLAND S OVER THE W ATLC W OF 70W TO A BASE NEAR 29N IN THE SW N ATLC. THIS TROUGH ALOFT SUPPORTS A FRONTAL SYSTEM ANALYZED AS A COLD FRONT FROM 30N73W SW TO 28N80W WHERE IT TRANSITIONS TO A STATIONARY FRONT OVER THE NE GULF OF MEXICO. AHEAD OF THE FRONT...A SURFACE TROUGH IS FROM 31N70W TO 28N75W TO THE FLORIDA STRAITS NEAR 24N81W. SCATTERED TO ISOLATED SHOWERS AND TSTMS ARE WITHIN 60 NM EITHER SIDE OF THE TROUGH AXIS. FARTHER EAST...AN UPPER LOW CONTINUE TO SUPPORT SCATTERED SHOWERS AND TSTMS FROM 20N TO 30N BETWEEN 62W AND 74W. SURFACE RIDGING DOMINATES ELSEWHERE ACROSS THE ATLC ALONG WITH FAIR WEATHER. FOR INFORMATION ABOUT TROPICAL WAVES SEE SECTION AT THE TOP OF THE DISCUSSION. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR