000 AXNT20 KNHC 060537 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT THU AUG 06 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 0515 UTC. ...SPECIAL FEATURES... A TIGHT PRESSURE GRADIENT BETWEEN W ATLC SURFACE RIDGING AND LOW PRESSURE OVER N COLOMBIA WILL SUPPORT GALE FORCE WINDS FROM 11N TO 13N BETWEEN 73W AND 76W THROUGH 1200 UTC THIS MORNING. SEAS OF 10 TO 16 FT CAN BE EXPECTED IN THE WARNED AREA. SEE THE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... AN EASTERN ATLC TROPICAL WAVE HAS AN AXIS FROM 17N34W TO 09N30W...MOVING W AT AROUND 15 KT OVER THE PAST 24 HOURS. THIS WAVE COINCIDES WITH AN INVERTED 700 MB TROUGH BETWEEN 29W AND 37W. MODERATE MOISTURE IS N OF 12N WITH HIGH MOISTURE S OF 12N. NO DEEP CONVECTION IS NOTED WITH THIS WAVE. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 19N16W THROUGH A 1010 MB LOW NEAR 12N20W TO 09N35W TO 09N41W...WHERE THE ITCZ BEGINS AND EXTENDS TO 08N48W. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 200 NM S OF THE MONSOON TROUGH BETWEEN 25W AND 40W. ISOLATED MODERATE CONVECTION IS WITHIN 100 NM S OF THE ITCZ AXIS. ...DISCUSSION... GULF OF MEXICO... AN UPPER RIDGE CENTERED OVER W TX HAS AN AXIS THAT EXTENDS E ACROSS THE N GULF. AN UPPER LOW OVER CENTRAL AMERICA HAS AN AXIS THAT EXTENDS N TO THE SW GULF. THE UPPER DIFFLUENCE FROM THE RIDGE SUPPORTS ISOLATED THUNDERSTORMS OVER THE NE GULF FROM 29N TO THE FL PANHANDLE BETWEEN 83W AND 87W. THE COMBINATION OF THE UPPER TROUGH AND A SURFACE TROUGH EXTENDING FROM 22N89W TO 18N92W OVER PORTIONS OF THE W YUCATAN PENINSULA SUPPORTS SCATTERED MODERATE CONVECTION WITHIN 100 NM OF THE SURFACE TROUGH AXIS. THE CONVECTION OVER THIS PORTION OF THE GULF IS DISSIPATING. A SURFACE RIDGE AXIS EXTENDS FROM ATLC HIGH PRESSURE...ACROSS FL...TO THE TX GULF COAST. GENTLE TO MODERATE ANTICYCLONIC WINDS COVER THE MAJORITY OF THE GULF BASIN THIS MORNING. CONVECTION WILL BE POSSIBLE OVER THE SW GULF AND THE NW GULF THROUGH TODAY. CARIBBEAN SEA... AN UPPER LOW OVER CENTRAL AMERICA NEAR GUATEMALA SUPPORTS CONVECTION WITHIN 30 NM OF THE COASTS OF HONDURAS AND BELIZE. AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 17N73W DOMINATES THE REMAINDER OF THE CARIBBEAN. ISOLATED MODERATE CONVECTION IS OCCURRING OVER THE GREATER ANTILLES AND OFFSHORE WATERS UNDER THE NORTHERN PERIPHERY OF THE RIDGE...FROM 18N TO 21N BETWEEN 72W AND 80W. A TIGHT PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE ATLC AND LOW PRESSURE OVER N COLOMBIA SUPPORTS GALE FORCE WINDS OVER A PORTION OF THE S CENTRAL CARIBBEAN THIS MORNING. PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS. MODERATE TO FRESH TRADE WINDS COVER MUCH OF THE REMAINDER OF THE BASIN. OVER THE NEXT 24 HOURS CONVECTION IS EXPECTED TO BE CONFINED N OF 18N W OF 72W...AND OVER THE SW CARIBBEAN. TRADE WINDS WILL RELAX SLIGHTLY LATER TODAY AS THE RIDGING OVER THE W ATLC WEAKENS. ...HISPANIOLA... MODERATE MOISTURE OVER THE AREA SUPPORTS ISOLATED SHOWERS AND THUNDERSTORMS THIS MORNING ACROSS THE ISLAND. SSMI TPW AND SATELLITE IMAGERY INDICATE THAT THIS AREA OF MOISTURE SHOULD REMAIN IN PLACE THROUGH TONIGHT...WHICH WILL CONTINUE TO SUPPORT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS. ATLANTIC OCEAN... A BROAD SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED NEAR 35N48W HAS AN AXIS THAT EXTENDS THROUGH A 1020 MB HIGH CENTERED NEAR 28N72W AND THEN CONTINUES W ACROSS THE FL PENINSULA. TWO WEAKNESSES ARE NOTED IN THE RIDGE IN THE FORM OF SURFACE TROUGHS. THE WESTERNMOST TROUGH EXTENDS FROM 29N63W TO 23N67W. ISOLATED SHOWERS AND THUNDERSTORMS ARE WITHIN 100 NM OF THE TROUGH AXIS. THE EASTERNMOST TROUGH EXTENDS FROM 28N55W TO 21N56W. THE NORTHERN PORTION OF THIS TROUGH IS INTERACTING WITH AN UPPER LOW CENTERED NEAR 27N59W TO SUPPORT SCATTERED THUNDERSTORMS FROM 25N TO 31N BETWEEN 50W AND 59W. FARTHER SOUTH...A 1013 MB LOW CENTERED NEAR 13N52W SUPPORTS A CLUSTER OF MODERATE CONVECTION WITHIN 75 NM OF THE LOW CENTER. A TROPICAL WAVE IS OVER THE EASTERN TROPICAL ATLC. PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS. OVER THE NEXT 24 HOURS CONVECTION WILL CONTINUE NEAR THE UPPER LOW. CONVECTION WILL ALSO BE POSSIBLE N OF 28N W OF 75W OVER THE W ATLC AS A TROUGH MOVES OFF THE SE US COAST LATER TODAY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO