000 AXNT20 KNHC 231751 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI OCT 23 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 1715 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 17N16W TO 11N30W TO A 1012 MB LOW NEAR 11N46W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM S OF THE TROUGH BETWEEN 19W-21W...AND ALSO WITHIN 60 NM NE QUADRANT OF THE LOW. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL ANTICYCLONE CYCLONE CENTERED NEAR 18N91W DOMINATES THE FLOW REGIME OVER MOST OF THE GULF OF MEXICO... AND THE WESTERN HALF OF THE CARIBBEAN. DIFFLUENT UPPER LEVEL SOUTHWESTERLY FLOW BETWEEN THE ANTICYCLONE AND AN UPPER CYCLONE OVER THE NORTHERN GREAT PLAINS ROCKIES IS HELPING TO SUPPORT A FEW CLUSTERS OF SCATTERED MODERATE CONVECTION N OF ABOUT 21N AND W OF 95W. BUOY OBSERVATIONS FROM THE NW GULF SHOW SE WINDS OF 15-20 KT WITH SEAS OF 8 FT. ANTICYCLONIC FLOW ON THE EASTERN PERIPHERY OF THE ANTICYCLONE IS SPREADING HIGH LEVEL MOISTURE...IN THE FORM OF CIRRUS CLOUDS...ACROSS MOST OF THE GULF W OF 85W WITH GENERALLY FAIR CONDITIONS AT THE SURFACE UNDER A HIGH PRESSURE RIDGE EXTENDING FROM THE SOUTHERN APPALACHIANS INTO THE GULF. LIGHT TO MODERATE NE WINDS PREVAIL OVER MOST OF THE GULF E OF 90W. EXPECT THE SE 15-20 KT WINDS OVER THE NW GULF TO INCREASE TO NEAR GALE FORCE LATE SAT INTO SUN WITH SEAS THERE TO BUILD TO POSSIBLY 12 OR 13 FT AS A FRONTAL LOW PRESSURE MOVES EASTWARD ALONG THE TEXAS COAST SUN AND INLAND OVER LOUISIANA BY LATE ON MON. THE LOW AND FRONT WILL ALSO INCREASE MOISTURE ALONG WITH SCATTERED SHOWERS AND TSTMS ACROSS MUCH OF THE NW AND N CENTRAL GULF LATE SAT THROUGH MON. CARIBBEAN SEA... THE UPPER-LEVEL ANTICYCLONE THAT DOMINATES THE GULF OF MEXICO ALSO EXTENDS SE COVERING THE CARIBBEAN W OF 74W. TO THE E...THE SOUTHERN PORTION OF AN UPPER-LEVEL TROUGH EXTENDS FROM THE EASTERN PART OF HISPANIOLA S TO NEAR 10N70W. A SURFACE TROUGH IS OVER THE FAR NW CARIBBEAN JUST E OF THE YUCATAN PENINSULA EXTENDING FROM COZUMEL TO 18N88W TO 16N86W. ISOLATED LOW TOPPED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE TROUGH AXIS. ISOLATED SHOWERS AND THUNDERSTORMS ARE WITHIN 180 NM E OF THE UPPER TROUGH N OF 15N...AND OVER AND NEAR THE WINDWARD PASSAGE. THE EASTERN END OF THE EASTERN PACIFIC MONSOON TROUGH IS OVER THE SW CARIBBEAN SUPPORTING SCATTERED MODERATE CONVECTION FROM ALONG THE COASTS OF PANAMA AND COSTA RICA N TO 11N BETWEEN 76W- 81W. ISOLATED MODERATE CONVECTION IS SEEN FROM 11N-14N W OF 81W. BUOY OBSERVATIONS AND LATEST SCATTEROMETER DATA SHOW MAINLY MODERATE TO FRESH TRADE WINDS ACROSS THE CARIBBEAN BASIN WITH THE STRONGEST WINDS OVER THE FAR NW CARIBBEAN N OF 18N W OF 85W TO THE YUCATAN CHANNEL. SCATTERED MODERATE CONVECTION OVER THE FAR SW CARIBBEAN SEA ALONG AND NEAR THE MONSOON TROUGH IS EXPECTED TO PERSIST OVER THE NEXT 24-48 HOURS...WHILE ISOLATED MODERATE CONVECTION CONTINUES OVER THE NE PART OF THE EASTERN CARIBBEAN AND WATERS BETWEEN JAMAICA AND THE WINDWARD PASSAGE. ...HISPANIOLA... A FRONTAL TROUGH JUST N OF THE N CENTRAL SECTION OF HISPANIOLA ...AND AN UPPER LEVEL TROUGH ALONG 70W IS SUPPORTING ISOLATED SHOWERS AND THUNDERSTORMS OVER THE ATLANTIC COASTAL WATERS OF THE DOMINICAN REPUBLIC. ISOLATED SHOWERS AND THUNDERSTORMS ARE ALSO OVER THE WINDWARD PASSAGE AREA AND NEAR THE COAST OF HAITI. WATER VAPOR IMAGERY SHOWS ABUNDANT MODERATE SUBSIDENCE AND ASSOCIATED DRIER AIR FILTERING SOUTHWARD FROM THE WESTERN ATLANTIC ACROSS HISPANIOLA AND TOWARDS THE CENTRAL CARIBBEAN SEA. THIS WILL CONTINUE THROUGH THE NEXT 24-48 HOURS AS THE UPPER TROUGH CONTINUES TO PUSH EASTWARD...AND WHILE BROAD UPPER- LEVEL HIGH PRESSURE REPLACES IT. PRECIPITABLE MOISTURE GUIDANCE FROM THE GFS SHOWS THE AXIS OF MOISTURE E OF THE UPPER TROUGH GRADUALLY SHIFTING EASTWARD OF THE EASTERN SECTION OF THE ISLAND INTO SUN. ATLANTIC OCEAN... A SHARP UPPER-LEVEL TROUGH OVER THE W ATLC STRETCHES FROM 31N70W TO N CENTRAL HISPANIOLA. THIS TROUGH CONTINUES TO SUPPORT A COLD FRONT THAT EXTENDS INTO THE DISCUSSION AREA FROM A 1009 MB LOW NEAR 31N60W SW TO 30N61W WHERE IT TRANSITIONS TO A STATIONARY FRONT TO A 1008 MB LOW NEAR 27N65W. A DISSIPATING STATIONARY FRONT THEN EXTENDS FROM THE LOW TO 23N66W WHERE IT BECOMES A FRONTAL TROUGH TO NEAR 19N69W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM EITHER SIDE OF THE STATIONARY FRONT N OF 27N. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 270 NM E OF THE DISSIPATING STATIONARY FRONT...WHILE ISOLATED MODERATE CONVECTION IS WITHIN 300 NM E OF THE FRONTAL TROUGH. WEAKENING ISOLATED MODERATE CONVECTION IS ALSO SEEN WITHIN 15 NM OF 29N71W. THE STATIONARY FRONT WILL WEAKEN FURTHER TO A TROUGH OVER THE NEXT 24 HOURS AS IT SLOWLY MOVES ESE. THE 1008 MB LOW IS FORECAST TO MOVE NE TO NEAR 30N61W WHILE DEEPENING TO 1005 MB...AND TO N OF THE AREA BY LATE SAT. SCATTERED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED WITHIN ABOUT 300 NM E OF THE TROUGH INCLUDING THE WATERS JUST N OF PUERTO RICO OVER THE NEXT 24 HOURS. SIMILAR ACTIVITY CAN ALSO BE EXPECTED NEAR THE 1007 MB LOW. LOW-LEVEL MOISTURE ON THE SOUTHERN PERIPHERY OF ATLANTIC RIDGING OVER THE PORTION W OF 70W WILL ADVECT ISOLATED LOW- TOPPED LIGHT SHOWERS AND SMALL PATCHES OF RAIN WESTWARD FROM THE BAHAMAS TOWARDS S FLORIDA...THE FLORIDA KEYS AND STRAITS OF FLORIDA THROUGH TONIGHT. SIMILAR SHOWER ACTIVITY..IN SMALL CLOUD LINES...IS NOTED N AND NE OF THE BAHAMAS. AN EASTERN ATLANTIC ELONGATED UPPER-LEVEL TROUGH SUPPORTS A 1010 MB SURFACE LOW PRESSURE CENTER NEAR 25N24W. A SURFACE TROUGH EXTENDS FROM THE LOW SW TO 23N26W...AND NW TO 24N31W. ANOTHER TROUGH EXTENDS FROM THE LOW NE TO NEAR 30N20W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 120 NM NE AND 75 NM N OF THE LOW. A STRONG JET STREAM BRANCH TO THE E OF THE UPPER TROUGH IS ADVECTING AMPLE MOISTURE TO THE NE OVER AND INLAND THE COAST OF AFRICA N OF ABOUT 17N AND E OF 19W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE OVER THE WESTERN SAHARA PORTION OF AFRICA...AND IN MOROCCO FROM 21N NORTHWARD BETWEEN 09W-17W. 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