000 AXNT20 KNHC 172350 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT OCT 17 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 2315 UTC. ...SPECIAL FEATURES... THE COMBINATION OF STRONG HIGH PRESSURE ACROSS EASTERN MEXICO... LOWER PRESSURE ACROSS CENTRAL AMERICA AND SOUTHERN MEXICO...AND A SURFACE TROUGH ANALYZED ACROSS THE SW GULF OF MEXICO WATERS IS SUPPORTING NEAR GALE TO GALE FORCE NW WINDS ALONG THE COAST OF VERACRUZ...MAINLY S OF 21N W OF 95W. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 09N37W TO 14N36W MOVING W AT 5-10 KT. THE WAVE COINCIDES WITH 700 MB TROUGHING BETWEEN 35W-43W. A WEAK 1012 MB CENTERED AT THE INTERSECTION OF THE SOUTHERN EXTENT OF THE WAVE AXIS AND THE MONSOON TROUGH INDICATES THE MAXIMUM LOW- LEVEL CYCLONIC ENERGY GENERATING SCATTERED MODERATE CONVECTION WITHIN 120 NM OF THE LOW CENTER. TROPICAL WAVE EXTENDS FROM 09N50W TO 17N53W MOVING W AT 5-10 KT. THE WAVE COINCIDES WITH A LOW-AMPLITUDE 700 MB TROUGH BETWEEN 47W-55W. IN ADDITION...A NEARBY UPPER LEVEL LOW CENTERED NEAR 22N57W IS INTERACTING WITH THE WAVE SHEARING MOST ONGOING CONVECTION TO THE EAST. ISOLATED MODERATE CONVECTION IS FROM 09N- 17N BETWEEN 45W-53W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 11N16W TO 08N20W TO 08N25W...THEN RESUMES IN THE VICINITY OF A 1012 MB LOW NEAR 13N27W TO A 1012 MB LOW NEAR 09N37W TO 08N41W. ISOLATED MODERATE CONVECTION IS FROM 03N-10N BETWEEN 15W- 29W...AND FROM 13N-20N BETWEEN 17W-25W. ...DISCUSSION... GULF OF MEXICO... BROAD LONGWAVE TROUGHING IS NOTED ON WATER VAPOR IMAGERY OVER THE EASTERN CONUS AND THE FAR WESTERN NORTH ATLC WATERS. THE TROUGHING SUPPORTS A PAIR OF FRONTAL BOUNDARIES ANALYZED ACROSS THE GULF THIS EVENING. FIRST...A STATIONARY FRONT EXTENDS FROM THE FLORIDA STRAITS NEAR 25N80W WESTWARD TO 24N92W AND PROVIDES LOW-LEVEL MOISTURE CONVERGENCE ACROSS THE SOUTHERN GULF FOR SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING MOSTLY S OF THE BOUNDARY ALONG 25N. ACROSS THE SW GULF...THE ADDITION OF A SURFACE TROUGH IN THE VICINITY OF 21N96W IS ALSO GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS ALONG WITH NEAR GALE TO GALE FORCE NW WINDS WEST OF THE BOUNDARY OFF THE COAST OF VERACRUZ. THE SECOND FRONT IS ANALYZED AS A COLD FRONT FROM 29N83W WESTWARD TO THE TEXAS COAST NEAR 28N97W. WHILE THE FRONT REMAINS NEARLY PRECIPITATION-FREE AT THIS TIME...SHIP...BUOY... AND OFFSHORE OIL PLATFORM OBSERVATIONS INDICATE A COOLER AND DRIER AIRMASS IN WAKE OF THE FRONT WHICH IS EXPECTED TO BECOME STATIONARY OVERNIGHT AND BEGIN GRADUALLY SLIDING SOUTHEASTWARD AGAIN ON SUNDAY. AS STRONG HIGH PRESSURE CONTINUES TO BUILD IN NORTH OF THE COLD FRONT AND THE PRESSURE GRADIENT ACROSS THE BASIN STRENGTHENS...STRONG NE WINDS ARE EXPECTED TO PERSIST THROUGH MONDAY. CARIBBEAN SEA... A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION INFLUENCES MUCH OF THE WESTERN CARIBBEAN AND CENTRAL AMERICA THIS EVENING PROVIDING AN OVERALL DIFFLUENT ENVIRONMENT ALOFT. AN AREA OF LOW PRESSURE ACROSS CENTRAL AMERICA FOCUSES ON A 1008 MB LOW CENTERED NEAR 18N89W. THE LOW IS ASSOCIATED WITH A LARGE AND BROAD MONSOONAL GYRE THAT COVERS A LARGE PORTION OF CENTRAL AMERICA AND A PORTION OF THE EASTERN PACIFIC WATERS N OF 10N BETWEEN 90W-100W. THE OVERALL CIRCULATION SUPPORTS SCATTERED SHOWERS AND TSTMS FROM 10N-23N WEST OF 78W...INCLUDING INLAND PORTIONS OF CENTRAL AMERICA...CUBA...AND THE YUCATAN PENINSULA. AS THE AREA OF LOW PRESSURE PERSISTS THROUGH THE REMAINDER OF THE WEEKEND... CONTINUED PRECIPITATION IS EXPECTED ACROSS THE WESTERN CARIBBEAN AND MORE IMPORTANTLY CENTRAL AMERICA RESULTING IN POSSIBLE FLASH FLOODING POTENTIAL AND MUD SLIDES. ELSEWHERE ACROSS THE EASTERN CARIBBEAN...DRIER AIR AND SUBSIDENCE ALOFT SUPPORTS GENERALLY FAIR WEATHER CONDITIONS E OF 78W WITH ONLY A FEW ISOLATED SHOWERS AND TSTMS OCCURRING ACROSS HISPANIOLA. MODERATE TO OCCASIONAL FRESH TRADE WINDS PREVAIL ACROSS THE BASIN WITH LITTLE CHANGE EXPECTED THROUGH EARLY NEXT WEEK. ...HISPANIOLA... CURRENTLY A FEW ISOLATED SHOWERS AND TSTMS LINGER ACROSS THE ISLAND DUE TO A RELATIVELY DIFFLUENT ENVIRONMENT ALOFT AND PEAK DAYTIME HEATING. THIS ACTIVITY SHOULD DIMINISH GRADUALLY THROUGH THE OVERNIGHT HOURS LEAVING ONLY ISOLATED...SHALLOW...AND WESTWARD MOVING LOW-LEVEL SHOWERS INTO EARLY SUNDAY. ATLANTIC OCEAN... A STATIONARY FRONT REMAINS IN PLACE FROM 31N69W SW TO THE FLORIDA STRAITS NEAR 25N80W AND DELINEATES A DIFFERENCE IN AIRMASSES...DEEP LAYER MOISTURE TO THE SOUTH AND DRIER COOLER AIR ACROSS THE SW NORTH ATLC WATERS AND FLORIDA PENINSULA TO THE NORTH AND WEST. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING GENERALLY WITHIN 300 NM SOUTHEAST OF THE FRONT. TO THE NW...A REINFORCING COLD FRONT EXTENDS FROM 32N77W TO THE FLORIDA PENINSULA NEAR DAYTONA BEACH. THESE TWO BOUNDARIES ARE EXPECTED TO MERGE LATE SUNDAY NIGHT INTO EARLY MONDAY. FARTHER EAST...A SURFACE TROUGH EXTENDS NORTH OF A TROPICAL WAVE FROM 19N54W TO 23N53W AND IS INTERACTING WITH AN UPPER LOW CENTERED NEAR 21N57W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING FROM 19N-26N BETWEEN 51W-59W. OTHERWISE...THE SUBTROPICAL HIGH REMAINS ANCHORED IN THE CENTRAL ATLC AT 1025 MB NEAR 33N43W. FINALLY...A VIGOROUS UPPER LEVEL LOW CENTERED NEAR 39N15W SUPPORTS A DISSIPATING COLD FRONT EXTENDING ACROSS NW AFRICA FROM 32N06W TO 23N16W TO 16N30W WHERE IT BECOMES A SHEAR LINE TO 16N38W TO 19N49W. ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE BOUNDARY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN