000 AXNT20 KNHC 081743 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE SEP 08 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 1730 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL DEPRESSION GRACE AT 08/1500 UTC IS NEAR 14.3N 42.8W. GRACE IS MOVING TOWARD THE W...OR 275 DEGREES...17 KT. THE MINIMUM CENTRAL PRESSURE IS 1007 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 30 KNOTS WITH GUSTS TO 40 KT. SCATTERED MODERATE CONVECTION IS FROM 14N-16N BETWEEN 39W-42W. PUBLIC ADVISORIES ABOUT TROPICAL DEPRESSION GRACE ARE BEING ISSUED UNDER THE WMO HEADER WTNT32 KNHC...AND UNDER THE AWIPS HEADER MIATCPAT2. FORECAST/ADVISORIES ARE BEING ISSUED UNDER THE WMO HEADER WTNT22 KNHC...AND UNDER THE AWIPS HEADER MIATCMAT2. A 1014 MB BROAD AREA OF LOW PRESSURE IS LOCATED AT ABOUT 300 MILES ESE OF BERMUDA NEAR 31N60W. SCATTERED MODERATE CONVECTION IS OBSERVED FROM 29N-34N BETWEEN 56W-62W. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BECOME FAVORABLE FOR DEVELOPMENT DURING THE NEXT COUPLE OF DAYS WHILE THE SYSTEM REMAINS NEARLY STATIONARY FOR AT LEAST 24 HOURS. AFTER THAT...THE SYSTEM WILL MOVE N AT AROUND 10 KT. THIS LOW HAS A MEDIUM CHANCE OF FORMATION OVER THE NEXT 48 HOURS. ...TROPICAL WAVES... A TROPICAL WAVE IS MOVING ACROSS THE E ATLANTIC WITH AXIS EXTENDING FROM 21N25W TO 08N25W...MOVING W AT 10 TO 15 KT. THIS POSITION IS A MEAN POSITION THAT IS BASED ON SATELLITE IMAGERY AND THE 700 MB WIND FIELD. SCATTERED MODERATE CONVECTION IS FROM 10N-16N BETWEEN 20W-28W. A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL ATLANTIC WITH AXIS EXTENDING FROM 17N51W TO 08N52W...MOVING W AT 15 KNOTS. TPW IMAGERY DEPICTS A HIGH MOISTURE CONTENT IN THE SOUTHERN PORTION OF THIS WAVE S OF 13N WHERE SCATTERED MODERATE CONVECTION IS OBSERVED FROM 07N-13N BETWEEN 49W-55W. A TROPICAL WAVE IS MOVING ACROSS THE E CARIBBEAN WITH AXIS EXTENDING FROM 18N64W TO 11N65W...MOVING W AT 15 KT. A LOW-LEVEL CIRCULATION IS TRYING TO FORM ALONG THE SOUTHERN PORTION OF THE WAVE SUPPORTING SCATTERED CONVECTION FROM 11N-15N BETWEEN 64W- 68W. A TROPICAL WAVE IS MOVING ACROSS THE W CARIBBEAN WITH AXIS EXTENDING FROM 20N79W TO 10N81W...MOVING W AT 10 TO 15 KNOTS. TPW IMAGERY SHOWS THAT THIS WAVE IS IN A DRY ENVIRONMENT AND NO CONVECTION IS OBSERVED AT THIS TIME. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH THE COAST OF AFRICA REACHING THE ATLANTIC OCEAN NEAR 19N16W AND EXTENDING TO 16N38W. ASIDE FROM THE CONVECTION OCCURRING DUE TO THE TROPICAL WAVE ALONG 25W...NO OTHER CONVECTION IS OBSERVED AT THIS TIME. ...DISCUSSION... GULF OF MEXICO... A BROAD SURFACE HIGH COVERS THE EASTERN CONUS AND EXTENDS ACROSS THE GULF WATERS. A WEAKNESS IN THIS HIGH IS ANALYZED AS A 1013 MB SURFACE LOW LOCATED NEAR 29N84W. ISOLATED MODERATE CONVECTION PREVAILS E OF 84W AND MOVING NE AFFECTING MOSTLY THE FLORIDA PENINSULA. TO THE W...AN ELONGATED UPPER-LEVEL LOW IS CENTERED OVER THE N-CENTRAL GULF NEAR 28N90W AND EXTENDS ACROSS THE BASIN SUPPORTING SCATTERED MODERATE CONVECTION S OF 28N BETWEEN 87W- 95W. SCATTEROMETER DATA DEPICTS LIGHT AND VARIABLE WINDS ACROSS THE GULF. WEAK RIDGING WILL CONTINUE ACROSS THE BASIN OVER THE NEXT 24-48 HOURS WHILE THE SURFACE LOW WILL MOVE N OVER THE FLORIDA PANHANDLE WITH CONVECTION. CARIBBEAN SEA... TWO TROPICAL WAVES ARE OVER THE BASIN. SEE THE TROPICAL WAVES SECTION FOR MORE DETAILS. THE EASTERN PORTION OF AN UPPER-LEVEL TROUGH EXTENDS FROM THE GULF OF MEXICO ACROSS THE W CARIBBEAN. THE W AND CENTRAL CARIBBEAN BETWEEN 72W-85W IS UNDER THE INFLUENCE OF AN UPPER-LEVEL HIGH CENTERED NEAR 12N80W. TO THE E...AN UPPER-LEVEL LOW EXTENDS FROM SOUTH AMERICA ACROSS THE SE CARIBBEAN BETWEEN 66W-72W WHILE THE WESTERN PORTION OF A WEAK ANTICYCLONE CENTERED OVER THE ATLANTIC EXTENDS ACROSS THE E CARIBBEAN MAINLY E OF 67W. ASIDE FROM THE CONVECTION RELATED TO THE TROPICAL WAVE ALONG 64W...THE ONLY CONVECTION OBSERVED ACROSS THE BASIN IS DUE TO THE PROXIMITY OF THE MONSOON TROUGH ACROSS THE SOUTHERN CARIBBEAN S OF 12N BETWEEN 80W-84W. SCATTEROMETER DATA DEPICTS GENTLE TO MODERATE TRADES ACROSS THE AREA BECOMING FRESH S OF 13N BETWEEN 72W-78W. OVER THE NEXT 24 HOURS...THE TROPICAL WAVES WILL CONTINUE MOVING W. CONVECTION WILL PREVAIL ACROSS THE SOUTHERN CARIBBEAN WITH THE MONSOON TROUGH. ...HISPANIOLA... FAIR WEATHER PREVAILS ACROSS THE ISLAND AT THIS TIME. AFTERNOON SHOWERS COULD BE EXPECTED DUE TO OROGRAPHIC LIFTING AND DAYTIME HEATING. A TROPICAL WAVE WILL MOVE ACROSS THE ISLAND WITHIN THE NEXT 24-48 HOURS SUPPORTING CONVECTION. ATLANTIC OCEAN... TROPICAL DEPRESSION GRACE IS MOVING ACROSS THE CENTRAL ATLANTIC. PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS. TWO TROPICAL WAVES ARE ALSO MOVING ACROSS THE TROPICAL ATLANTIC. PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS. UPPER-LEVEL DIFFLUENCE IS SUPPORTING ISOLATED MODERATE CONVECTION ACROSS THE W ATLANTIC MAINLY W OF 77W. THE MAJORITY OF THE BASIN IS UNDER THE INFLUENCE OF A SURFACE RIDGE...ANCHORED BY A 1018 MB HIGH NEAR 26N64W AND A 1021 MB HIGH CENTERED NEAR 29N28W. TO THE N OF THE RIDGE...A STATIONARY FRONT EXTENDS FROM 35N74W TO A 1014 MB LOW NEAR 31N60W TO 29N46W TO 32N31W. ASIDE FROM THE CONVECTION RELATED TO THE LOW PRESSURE ...SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS...ISOLATED MODERATE CONVECTION IS OBSERVED N OF 29N BETWEEN 62W-70W AND N OF 29N BETWEEN 38W-42W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA