000 AXNT20 KNHC 092353 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI OCT 09 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS AT ABOUT 170 NM W OF THE CAPE VERDE ISLANDS WITH AXIS EXTENDING FROM 20N26W TO 10N28W...MOVING W AT 10-15 KT. VISIBLE SATELLITE IMAGERY DEPICTS AN INVERTED-V PATTERN IN THE CLOUD FIELD AND LATEST GFS 700 MB STREAMLINES ALSO SHOW AN INVERTED TROUGH NEAR 24W-30W. TPW IMAGERY SHOWS THAT THE WAVE IS EMBEDDED IN A SURGE OF MOISTURE SUPPORTING SCATTERED MODERATE CONVECTION W OF THE WAVE AXIS FROM 11N-16N AND W OF 29W WHERE IT COMBINES WITH THE ITCZ CONVECTION. A LOW AMPLITUDE TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH AXIS EXTENDING FROM 16N46W TO 10N46W. AFRICAN DUST SURROUNDS THE WAVE AS NOTED ON THE SAHARAN AIR LAYER FROM UW-CIMSS. ISOLATED MODERATE CONVECTION IS NEAR THE SOUTHERN END OF THE WAVE AXIS S OF 12N BETWEEN 42W-47W. A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN WITH AXIS EXTENDING FROM 19N69W TO 12N69W...MOVING OVER DOMINICAN REPUBLIC AT ABOUT 10-15 KT. THE TPW IMAGERY INDICATES A BULGE OF MOISTURE IN ASSOCIATION WITH THIS WAVE. THIS SYSTEM IS WELL DEPICTED IN THE LATEST GFS 700 MB STREAMLINES AND 850 MB VORTICITY ANALYSIS. THE WAVE COMBINED WITH AN UPPER-LEVEL LOW CENTERED S OF HISPANIOLA ARE ENHANCING SCATTERED MODERATE CONVECTION BETWEEN 65W-73W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO NEAR 13N23W. THE ITCZ AXIS BEGINS W OF A TROPICAL WAVE NEAR 11N32W TO 09N46W TO 09N61W. ASIDE OF THE CONVECTION RELATED TO THE TROPICAL WAVES DISCUSSED IN THE SECTION ABOVE... SCATTERED MODERATE CONVECTION IS FROM 08N-12N BETWEEN 32W-58W. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH PERSISTS OVER THE EASTERN GULF AND STRETCHES FROM 29N84W TO 23N90W. ISOLATED CONVECTION IS OBSERVED ALONG THE NORTHERN PORTION OF THIS BOUNDARY. A SURFACE RIDGE PREVAILS ACROSS THE WESTERN CONUS AND EXTENDS ACROSS MEXICO REACHING THE GULF. ISOLATED CONVECTION IS MOVING FROM THE NE COAST OF MEXICO OVER THE GULF WATERS MAINLY N OF 24N AND W OF 96W. LOOKING AHEAD...A WEAK COLD FRONT IS FORECAST TO REACH THE NORTHERN GULF BY SATURDAY EXTENDING ACROSS THE SE AND SOUTH-CENTRAL GULF BY SUNDAY WHERE IT WILL GRADUALLY DISSIPATE. WEAK HIGH PRESSURE WILL FOLLOW THE FRONT. ALOFT...AN ANTICYCLONE CENTERED OVER THE SW GULF EXTENDS A RIDGE ACROSS THE ENTIRE REGION AND THE STATE OF FLORIDA. CARIBBEAN SEA... THE TROPICAL WAVE CURRENTLY LOCATED OVER EASTERN HISPANIOLA ALONG 69W AND WILL MOVE ACROSS THE CENTRAL CARIBBEAN TONIGHT THROUGH LATE SATURDAY NIGHT AND ACROSS THE WESTERN CARIBBEAN ON SUNDAY. FOR MORE INFORMATION...PLEASE REFER TO THE SECTION ABOVE. LATEST SCATTEROMETER PASSES DEPICT FRESH TRADE WINDS ACROSS THE SOUTH-CENTRAL CARIBBEAN S OF 15N BETWEEN 67W-72W WHILE GENTLE TO MODERATE TRADES PREVAIL ELSEWHERE. THIS PATTERN IS FORECAST TO PERSIST OVER THE NEXT SEVERAL DAYS WITH FRESH TO LOCALLY STRONG TRADE WINDS NEAR THE COAST OF WESTERN VENEZUELA AND NORTHERN COLOMBIA AT NIGHT. THE TRADES WILL CARRY ISOLATED TO SCATTERED SHOWERS ACROSS THE BASIN. A SIMILAR WEATHER PATTERN IS EXPECTED OVER THE NEXT 24 HOURS. ...HISPANIOLA... THE UPPER-LEVEL LOW LOCATED S OF THE ISLAND COMBINED WITH THE PASSAGE OF A TROPICAL WAVE AND THE LOCAL EFFECTS AS DAYTIME HEATING...LOCAL SEA BREEZES AND MOUNTAIN SLOPES...TO INCREASE THE CONVECTION ACTIVITY ACROSS THE AREA. LOCALLY HEAVY RAINFALL COULD BE POSSIBLE AND GUSTY WINDS DUE TO THE PRESENCE OF THE TSTMS. BY SUNDAY...THE UPPER-LEVEL LOW IS EXPECTED TO DISSIPATE AND A STRONG UPPER-LEVEL TROUGH IS FORECAST TO APPROACH FROM THE W. ATLANTIC OCEAN... A WEAK 1015 MB SURFACE LOW IS ALONG THE E COAST OF FLORIDA NEAR 28N80W. VISIBLE SATELLITE IMAGERY AND DOPPLER RADAR FROM MELBOURNE SHOWED THE CYCLONIC CIRCULATION ASSOCIATED WITH THIS LOW. THIS SYSTEM IS LIKELY ASSOCIATED WITH AN OLD FRONTAL BOUNDARY THAT WAS ANALYZED AS A WEAK STATIONARY FRONT FROM 28N80W TO 31N67W THEN AS A COLD FRONT FROM THAT POINT TO A 1012 MB LOW CENTERED NEAR 33N64W. TO THE E...A SURFACE TROUGH...LIKELY PART OF THE ENERGY ASSOCIATED WITH THE TROPICAL WAVE LOCATED OVER THE E CARIBBEAN...RUNS FROM 26N65W TO 20N67W. SCATTERED MODERATE CONVECTION IS NOTED ON THE E SIDE OF THE TROUGH SUPPORTED BY UPPER-LEVEL DIFFLUENCE. A 1020 MB SURFACE HIGH IS LOCATED NEAR 28N49W. A WEAKENING COLD FRONT WAS ANALYZED FROM 23N43W TO 31N19W WITH ISOLATED CONVECTION. EXPECT FOR THE FRONTS TO WEAKEN WITHIN THE NEXT 24 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA