000 AXNT20 KNHC 201143 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE OCT 20 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO A 1011 MB LOW NEAR 09N28W TO ANOTHER 1011 MB LOW NEAR 10N39W TO 10N44W. SCATTERED MODERATE CONVECTION IS FROM 02N-16N AND E OF 33W. ISOLATED MODERATE CONVECTION IS FROM 06N-13N BETWEEN 35W-42W. ...DISCUSSION... GULF OF MEXICO... AN UPPER-LEVEL TROUGH OVER THE NW ATLANTIC SUPPORTS A FRONTAL SYSTEM ANALYZED AS A STATIONARY FRONT ACROSS THE SE GULF OF MEXICO FROM 25N88W TO 25N81W. ISOLATED SHOWERS ARE ALONG THE FRONT. TO THE E...A SURFACE TROUGH PREVAILS NEAR THE BAY OF CAMPECHE EXTENDING FROM 27N93W TO 20N92W WITH ISOLATED CONVECTION. SCATTEROMETER DATA AND LATEST SURFACE OBSERVATIONS DEPICT A MODERATE TO FRESH EASTERLY FLOW PREVAILS ACROSS THE EASTERN HALF OF THE BASIN WHILE A GENTLE TO MODERATE N-EASTERLY FLOW PREVAILS ACROSS THE WESTERN GULF. OVER THE NEXT 24 HOURS...THE FRONTAL BOUNDARY WILL BEGIN WEAKENING WITH ISOLATED CONVECTION STILL POSSIBLE. DISSIPATION IS EXPECTED THROUGH MID WEEK. CARIBBEAN SEA... UPPER-LEVEL RIDGING EXTENDS OVER CENTRAL AMERICA IS COVERING THE WESTERN HALF OF THE BASIN WHILE AN ELONGATED UPPER-LEVEL LOW PREVAILS ACROSS THE SE CARIBBEAN AND EXTENDS NE ACROSS THE TROPICAL ATLANTIC. AT THE SURFACE...A SURFACE TROUGH PREVAILS ACROSS THE WESWTEN CARIBBEAN EXTENDING FROM 21N86W TO 16N87W. SCATTERED MODERATE CONVECTION IS OBSERVED IN THE VICINITY OF THE TROUGH MAINLY W OF 82W SUPPORTED BY A DIFFLUENT FLOW ALOFT. A SIMILAR DIFFLUENT FLOW IS ALSO NOTED OVER CUBA AND HISPANIOLA SUPPORTING ISOLATED MODERATE CONVECTION OVER THE ISLANDS AND ADJACENT WATERS. DRY AIR AND SUBSIDENCE PERSISTS ACROSS THE CENTRAL AND E CARIBBEAN INHIBITING CONVECTION EXCEPT DIURNAL ACTIVITY OVER THE GREATER ANTILLES. GENTLE TO MODERATE TRADES PREVAIL ACROSS THE BASIN AS NOTED IN SCATTEROMETER DATA. OVER THE NEXT 24 HOURS...CONVECTION WILL CONTINUE OVER THE NW CARIBBEAN. ...HISPANIOLA... A DIFFLUENT FLOW PREVAILS OVER THE ISLAND SUPPORTING ISOLATED MODERATE CONVECTION ACROSS THE NORTHERN HALF. THIS PATTERN COMBINED WITH DIURNAL HEATING IS EXPECTED TO ENHANCE MORE CONVECTION IN THE AFTERNOON/EVENING HOURS ACROSS THE WHOLE ISLAND. ATLANTIC OCEAN... A BROAD MID/UPPER-LEVEL TROUGH MOVING ACROSS THE NW ATLANTIC CONTINUES TO SUPPORT TO A FRONTAL SYSTEM THAT BEGINS AS A STATIONARY FRONT FROM 25N80W TO 25N73W THEN TRANSITIONS INTO A COLD FRONT FROM THAT LAST POINT TO 27N71W TO 31N53W. A PRE- FRONTAL TROUGH IS SE OF THE COLD FRONT AND EXTENDS FROM 22N63W TO 31N51W. CLUSTERS OF MODERATE CONVECTION PREVAIL ACROSS THE W ATLANTIC MAINLY W OF 51W. TO THE S...A SURFACE TROUGH IS AT ABOUT 440NM E OF THE WINDWARD ISLANDS EXTENDING FROM 14N53W TO 09N54W. A DIFFLUENT FLOW ALOFT IS SUPPORTING ISOLATED CONVECTION E OF THIS SURFACE TROUGH FROM 13N-19N BETWEEN 43W-52W. FURTHER E...A FRONTAL SYSTEM WAS ANALYZED AS A STATIONARY FRONT FROM 23N23W TO 24N15W THEN TRANSITIONS INTO A COLD FRONT ACROSS NW AFRICA. ISOLATED CONVECTION IS ALONG THE FRONTS. NEAR GALE FORCE WINDS ARE POSSIBLE N OF 32N E OF 15W DUE TO A STRONG PRESSURE GRADIENT BEHIND THIS COLD FRONT. OVER THE NEXT 24 HOURS... CONVECTION WILL CONTINUE SE OF THE COLD FRONT OVER THE W ATLANTIC AS IT GRADUALLY TRANSITIONS TO A STATIONARY FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA