000 AXNT20 KNHC 280538 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SUN JUN 28 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 0530 UTC. ...SPECIAL FEATURES... ...GALE WARNING IN THE CARIBBEAN SEA... GALE FORCE WINDS ARE FORECAST TO RESUME TONIGHT BEGINNING AT 0600 UTC FROM 11.5N-16N BETWEEN 70W-78W. SEAS OF 11 TO 17 FT CAN BE EXPECTED ACROSS THIS AREA. THESE WINDS ARE BEING GENERATED BY A TIGHT PRESSURE GRADIENT BETWEEN A STRONG HIGH PRESSURE OVER THE WESTERN ATLANTIC AND LOWER PRESSURES OVER NORTHERN COLOMBIA AND THE SW CARIBBEAN SEA. SEE THE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC AND THE OFFSHORE FORECAST...MIAOFFNT3/ FZNT23 FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLANTIC WITH AXIS EXTENDING FROM 11N41W TO 04N42W...MOVING W AT 20 TO 25 KT. SSMI TOTAL PRECIPITABLE WATER IMAGERY INDICATES THAT THIS WAVE IS EMBEDDED IN A DEEP MOIST ENVIRONMENT S OF 11N...WHILE A SAHARAN AIR LAYER PREVAILS N OF 08N. ISOLATED MODERATE CONVECTION IS OBSERVED N OF 09N BETWEEN 41W-43W. A TROPICAL WAVE IS CURRENTLY ENTERING THE E CARIBBEAN...WITH AXIS EXTENDING FROM 17N61W TO 09N62W. THIS WAVE IS MOVING W AT 15 TO 20 KT. SSMI TPW IMAGERY SHOWS THIS WAVE ALSO EMBEDDED IN DEEP MOISTURE MAINLY S OF 12N AND A SAHARAN AIR LAYER TO THE N OF 12N. NO SIGNIFICANT CONVECTION IS RELATED TO THIS WAVE. A TROPICAL WAVE MOVING ACROSS THE CENTRAL CARIBBEAN WITH AXIS EXTENDING FROM 20N71W TO 11N73W...MOVING W AT AROUND 15 KT. WATER VAPOR IMAGERY INDICATES THE NORTHERN PORTION OF THE WAVE IS INTERACTING WITH A MID-LEVEL TROUGH THAT EXTENDS ACROSS THE NORTHERN CARIBBEAN FROM THE SW ATLANTIC. THIS INTERACTION GENERATED ISOLATED CONVECTION ACROSS HISPANIOLA. NO DEEP CONVECTION IS NOTED S OF THE ISLAND DUE TO THE PRESENCE OF SAHARAN DUST. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA REACHING THE TROPICAL ATLANTIC NEAR 11N16W TO 07N28W...WHERE THE ITCZ BEGINS AND CONTINUES TO 07N39W...THEN RESUMES W OF A TROPICAL WAVE NEAR 06N43W TO 05N52W. SCATTERED MODERATE CONVECTION IS WITHIN 50 NM OF THE ITCZ AND MONSOON TROUGH AXES MAINLY E OF 33W...AND WITHIN 50 NM OF THE ITCZ AXIS BETWEEN 45W-47W. ...DISCUSSION... GULF OF MEXICO... AN UPPER-LEVEL LOW IS CENTERED OVER THE WESTERN GULF NEAR 25N96W WHILE AN UPPER-LEVEL ANTICYCLONE PREVAILS OVER THE SOUTHERN PORTION OF THE FLORIDA PENINSULA. THESE FEATURES ARE GENERATING A DIFFLUENT FLOW ACROSS THE CENTRAL GULF WHICH SUPPORTS CLOUDINESS AND ISOLATED CONVECTION BETWEEN 87W-94W. AT THE SURFACE...A 1019 MB HIGH PRESSURE IS CENTERED NEAR 25N85W SUPPORTING A LIGHT TO GENTLE ANTICYCLONIC FLOW ACROSS THE BASIN. SCATTERED MODERATE CONVECTION IS DEVELOPING ACROSS THE SOUTHERN PORTIONS OF TEXAS...LOUISIANA AND MISSISSIPPI AHEAD OF A FRONTAL SYSTEM THAT IS DIGGING SOUTHWARD ACROSS SOUTHERN US. SOME OF THIS ACTIVITY IS REACHING THE NORTHERN GULF MAINLY N OF 29N. OVER THE NEXT 24 HOURS...EXPECT FOR CONVECTION TO PREVAIL ACROSS THE NORTHERN GULF AS THE FRONT CONTINUES MOVING SE. CARIBBEAN SEA... A DIFFLUENT ENVIRONMENT PREVAILS ACROSS THE W CARIBBEAN SUPPORTING ISOLATED CONVECTION MAINLY W OF 85W. TO THE E...AN UPPER-LEVEL TROUGH ORIGINATED ACROSS THE SW ATLANTIC EXTENDS SW ACROSS THE WINDWARD PASSAGE REACHING THE NW PORTION OF THE BASIN. THIS FEATURE IS GENERATING CLOUDINESS AND ISOLATED CONVECTION ACROSS HISPANIOLA AND N OF THE ISLAND. TWO TROPICAL WAVES ARE OBSERVED ACROSS THE CENTRAL AND E CARIBBEAN...FOR MORE INFORMATION PLEASE REFER TO THE SECTION ABOVE. A STRONG PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE OVER THE WESTERN ATLANTIC AND LOWER PRESSURES OVER S AMERICA SUPPORTS GENTLE TO MODERATE TRADE WINDS OVER THE MAJORITY OF THE CARIBBEAN...WITH AN AREA OF HIGHER WINDS PREVAILING OVER THE S-CENTRAL CARIBBEAN. THE PRESSURE GRADIENT WILL TIGHTEN LATER TONIGHT WHICH WILL INCREASE WINDS TO GALE FORCE LATE TONIGHT OVER THE SOUTHERN CARIBBEAN. PLEASE SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. OVER THE NEXT 24 HOURS...EXPECT A SLIGHT INCREASE IN CONVECTION OVER THE EASTERN CARIBBEAN AS A TROPICAL WAVE CROSSES MOVES THROUGH THE LEEWARD ISLANDS AND PUERTO RICO. ...HISPANIOLA... A TROPICAL WAVE IS CURRENTLY OVER THE ISLAND BRINGING A MOIST AIRMASS TO THE AREA. DESPITE THIS...FAIR WEATHER PREVAILS ACROSS THE AREA AT THIS MOMENT. AN UPPER-LEVEL TROUGH EXTENDS FROM THE SW ATLANTIC ACROSS THE WINDWARD PASSAGE. THIS WILL SUPPORT CONVECTION THIS AFTERNOON AS THIS FEATURE COMBINES WITH DIURNAL HEATING AND OROGRAPHIC LIFTING. ATLANTIC OCEAN... AN UPPER-LEVEL LOW IS CENTERED ACROSS THE SW ATLANTIC NEAR 26N69W SUPPORTING CLOUDINESS AND ISOLATED CONVECTION S OF 26N BETWEEN 63W-70W. A 1027 MB SURFACE HIGH PREVAILS ACROSS THE REMAINDER OF THE BASIN CENTERED NEAR 29N52W. A LARGE SAHARAN AIRMASS ALSO PREVAILS ACROSS THE ATLANTIC. WITH THIS...FAIR WEATHER PREVAILS ACROSS THE BASIN. OVER THE NEXT 24 HOURS... EXPECT CONVECTION TO DEVELOP OFFSHORE FL MAINLY N OF THE BAHAMAS AS AN UPPER-LEVEL TROUGH MOVES OFF THE SE US COAST. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA