000 AXNT20 KNHC 111802 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE AUG 11 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 EAST OF THE CAPE VERDE ISLANDS WITH AXIS NEAR 22W...MOVING W AT APPROXIMATELY 5 KT. CIRA LAYER PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW MODERATE MOISTURE ASSOCIATED WITH THIS WAVE. HOWEVER...METEOSAT ENHANCED IMAGERY SHOW SAHARAN DRY AIR AND DUST IN THE WAVE ENVIRONMENT...WHICH SUPPRESS CONVECTION. A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AXIS NEAR 44W...MOVING W AT APPROXIMATELY 10 KT. CIRA LAYER PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW THE WAVE IS MAINLY EMBEDDED IN A DRY 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 IN THE EASTERN CARIBBEAN WITH AXIS NEAR 66W MOVING W AT APPROXIMATELY 15-20 KT. CIRA LAYER PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW A MODERATE MOIST ENVIRONMENT E OF THE WAVE AXIS THAT ENHANCES SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE LESSER ANTILLES...PUERTO RICO AND ADJACENT WATERS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 12N16W TO 08N30W TO 07N45W. THE ITCZ BEGINS NEAR 07N45W TO GUYANA COASTAL WATERS NEAR 06N56W. SCATTERED MODERATE CONVECTION IS FROM 05N TO 10N BETWEEN 13W AND 20W...FROM 07N TO 09N BETWEEN 21W AND 28W AND FROM 06N TO 09N BETWEEN 37W AND 47W. ...DISCUSSION... ...THE GULF OF MEXICO... BROAD SURFACE HIGH PRESSURE OVER THE ATLC EXTENDS A RIDGE AXIS W- SW ACROSS THE FLORIDA PENINSULA...THE NORTHERN AND EASTERN GULF OF MEXICO. OVER THE W-SW BASIN...A 1014 MB LOW IS LOCATED NEAR 25N92W ENHANCING SCATTERED SHOWERS AND TSTMS FROM 23N TO 26N W OF 92W. A SURFACE TROUGH IS SW OF THE LOW FROM 24N96W TO 19N96W SUPPORTING SIMILAR CONVECTION FROM 20N TO 22N W OF 95W. CIRA LAYER PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW MODERATE MOISTURE STREAMING ACROSS THE BASIN FROM THE CARIBBEAN...HOWEVER DRY AIR SUBSIDENCE FROM ALOFT AND STRONG DEEP LAYER WIND SHEAR HINDER CONVECTION ELSEWHERE. WINDS ACROSS THE BASIN ARE VARIABLE RANGING FROM 5 TO 10 KT. SHOWERS AND TSTMS OVER THE W-SW GULF ARE EXPECTED TO CONTINUE DURING THE NEXT TWO HOURS...ACCORDING TO THE GOES-R CONVECTIVE INITIATION PRODUCT. A WEAK COLD FRONT IS FORECAST TO ENTER THE N-NE GULF WED MORNING...BECOMING STATIONARY THURSDAY. ...THE CARIBBEAN SEA... A TROPICAL WAVE IS MOVING ACROSS THE EASTERN CARIBBEAN ENHANCING SHOWERS ACROSS PUERTO RICO AND THE LESSER ANTILLES. SEE TROPICAL WAVES SECTION FOR DETAILS. SHALLOW MODERATE MOISTURE DOMINATES ACROSS THE NW AND SW BASIN. AN UPPER LEVEL LOW OVER THE YUCATAN PENINSULA SUPPORTS SCATTERED TO ISOLATED SHOWERS AND TSTMS OVER THE NW CARIBBEAN S OF 21N W OF 82W. UPPER LEVEL DIVERGENCE ALONG THE EASTERN CENTRAL AMERICA COASTLINE SUPPORT HEAVY SHOWERS AND TSTMS S OF 16N W OF 78W. FAIR WEATHER IS OVER THE CENTRAL CARIBBEAN SUPPORTED BY DRY AIR AND STRONG DEEP LAYER WIND SHEAR. NE TO E WINDS OF 20 TO 25 KT ARE FROM 11N TO 14N BETWEEN 71W AND 78W WITH SEAS TO 10 FT. TRADES OF 15 KT DOMINATE ELSEWHERE. THE TROPICAL WAVE IS FORECAST TO MOVE ACROSS HISPANIOLA AND CENTRAL CARIBBEAN WEDNESDAY ENHANCING SHOWERS. ...HISPANIOLA... DEEP LAYER DRY AIR DOMINATES ACROSS THE ISLAND AND IS EXPECTED TO CONTINUE THROUGH TONIGHT. ON WEDNESDAY MORNING...A TROPICAL WAVE WILL START TO MOVE ACROSS THE CENTRAL CARIBBEAN ENHANCING SHOWERS ACROSS THE ISLAND THROUGH THURSDAY MORNING. THE ATLANTIC OCEAN... SHALLOW MOISTURE OVER THE SW N ATLC ASSOCIATED WITH A FORMER FRONTAL SYSTEM AND A TROUGH OF LOW PRESSURE CONTINUE TO ENHANCE ISOLATED SHOWERS AND TSTMS OVER THE NORTHERN AND CENTRAL BAHAMAS AND FARTHER NE FROM 26N TO 31N BETWEEN 65W AND 71W. OTHERWISE...SURFACE HIGH PRESSURE SUPPORT FAIR WEATHER ELSEWHERE N OF 20N. FOR INFORMATION ABOUT TROPICAL WAVES SEE SECTION AT THE TOP OF THE DISCUSSION. A COLD FRONT IS FORECAST TO ENTER THE SW N ATLC LATE WEDNESDAY...STALLING OVER THIS REGION OF THE BASIN THURSDAY AND FRIDAY. SURFACE RIDGING WILL DOMINATE ELSEWHERE. TONIGHT...NE TO E WINDS OF 20 TO 25 KT ARE FORECAST S OF 21N BETWEEN 70W AND 72W WITH SEAS LESS THAN 8 FT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR