000 AXNT20 KNHC 190604 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED AUG 19 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0545 UTC. ...SPECIAL FEATURES... TROPICAL STORM DANNY IS LOCATED NEAR 11.2N 38.8W AT 0300 UTC...MOVING W-NW AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 04N TO 13N BETWEEN 34W AND 47W. SOME ADDITIONAL STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS AND DANNY IS EXPECTED TO BECOME A HURRICANE BY THURSDAY. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS TCMAT4/WTNT24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS EAST OF THE CAPE VERDE ISLANDS WITH AXIS NEAR 20W...MOVING W AT 5-10 KT OVER THE PAST 18 HOURS. CIRA LAYER PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS WITHIN A MODERATE MOIST ENVIRONMENT EXTENDING FROM THE SURFACE TO 700 MB. HOWEVER...METEOSAT ENHANCED IMAGERY SHOW SAHARAN DRY AIR AND DUST IN THE WAVE ENVIRONMENT...WHICH IS KEEPING A WAVE DEVOID OF CONVECTION. A TROPICAL WAVE IS WITHIN 370 NM E-SE OF THE LESSER ANTILLES WITH AXIS NEAR 55W...MOVING W AT 10-15 KT OVER THE PAST 24 HOURS. CIRA LAYER PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS WITHIN A MODERATE MOIST ENVIRONMENT EXTENDING FROM THE SURFACE TO 850 MB THAT ENHANCES SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS FROM 08N TO 12N BETWEEN 53W AND 58W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 20N16W TO E OF THE TROPICAL WAVE NEAR 17N18W THEN RESUMES W OF THE TROPICAL WAVE NEAR 13N21W TO E OF T.S. DANNY NEAR 12N33W. THE ITCZ BEGINS W OF T.S. DANNY NEAR 10N43W TO E OF THE WESTERNMOST TROPICAL WAVE NEAR 08N54W. ASIDE THE CONVECTION ASSOCIATED WITH DANNY AND THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS FROM 07N TO 14N BETWEEN 23W AND 33W. ...DISCUSSION... GULF OF MEXICO... A BROAD MIDDLE TO UPPER LEVEL RIDGE CONTINUE OVER THE GULF ANCHORED NEAR 26N87W...WHICH IS SUPPORTING AN OVERALL STABLE ENVIRONMENT ACROSS THE BASIN. BROAD SURFACE HIGH PRESSURE ACROSS THE ATLC EXTENDS A RIDGE AXIS W-SW ACROSS THE FLORIDA PENINSULA TO THE SW GULF...THUS PROVIDING SE WIND FLOW OF LESS THAN 15 KT BASIN-WIDE. SURFACE RIDGING OVER THE GULF IS BEING ANCHORED BY A 1017 MB HIGH NEAR 29N83W. A WEAKNESS IN THE RIDGE IS BEING ANALYZED AS A SURFACE TROUGH FROM JACKSONVILLE COASTAL WATERS SW ACROSS SOUTHERN FLORIDA TO THE KEYS...WHICH ALONG WITH MOISTURE INFLOW ACROSS THE BASIN FROM THE CARIBBEAN SEA SUPPORT ISOLATED SHOWERS AND TSTMS S OF 28N E OF 83W. SURFACE RIDGE WILL EXTEND ACROSS THE N GULF THROUGH THU. CARIBBEAN SEA... AN UPPER LOW COVERS THE CARIBBEAN W OF 74W GENERATING A DIFFLUENT ENVIRONMENT OVER THE FAR NW BASIN...WHICH ALONG WITH SHALLOW MOISTURE SUPPORT SHOWERS AND THUNDERSTORMS N OF 21N BETWEEN 81W AND 83W...INCLUDING WESTERN CUBA. SIMILAR CONVECTION IS OBSERVED WITHIN 60 NM OFF THE COASTS OF COSTA RICA AND NORTHERN PANAMA. DRY AIR AND STRONG DEEP LAYER WIND SHEAR HINDER CONVECTION ELSEWHERE ACROSS THE CARIBBEAN. FRESH TO STRONG TRADES WILL CONTINUE OVER THE S/CENTRAL CARIBBEAN INCREASING TO NEAR GALE FORCE OFF THE NW COAST OF COLOMBIA ON WED NIGHT. TROPICAL WAVE WILL ENTER THE E CARIBBEAN WED THEN INTO THE CENTRAL CARIBBEAN THU. ...HISPANIOLA... EXCEPT FOR HAITI AND THE WINDWARD PASSAGE WHERE MODERATE SHALLOW MOISTURE IS OBSERVED IN CIRA LAYER PRECIPITABLE WATER IMAGERY...DEEP LAYER DRY AIR IS OVER THE ISLAND SUPPORTING FAIR WEATHER. CLOUDINESS AND POSSIBLE ISOLATED SHOWERS ARE MAINLY OFF THE WESTERN COAST OF HAITI. THERE WILL BE A MOISTURE INCREASE THU NIGHT AS A TROPICAL WAVE MOVES ACROSS THE ISLAND WITH SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS. ATLANTIC OCEAN... THE MAIN FEATURE IN THE BASIN IS TROPICAL STORM DANNY WHICH IS FORECAST TO STRENGTHEN INTO A HURRICANE DURING THE NEXT COUPLE OF DAYS. SEE SPECIAL FEATURES FOR MORE DETAILS. THE SECOND FEATURE OF INTEREST ARE TWO TROPICAL WAVES DISCUSSED IN THE WAVES SECTION. OTHERWISE...THE ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1025 MB HIGH OVER THE AZORES AND A WEAK 1021 MB HIGH NEAR 29N48W. THE SURFACE RIDGE ACROSS THE W ATLC WILL SHIFT S AS A WEAK TROUGH PASSES E ACROSS N PORTION OF THE W ATLC S OF BERMUDA ON WED WITH LOW DEVELOPING NEAR S OF BERMUDA ON THU NIGHT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR