000 AXNT20 KNHC 171742 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... THE COMBINATION OF STRONG HIGH PRES BUILDING OVER THE MISSISSIPPI VALLEY...LOWER PRES OVER CENTRAL AMERICA...AND A SURFACE TROUGH OVER THE SW GULF WILL SUPPORT SUSTAINED WINDS TO GALE FORCE ALONG THE COAST OF VERACRUZ...MAINLY S OF 21N W OF 95W...THROUGH EARLY NEXT WEEK. PLEASE REFER TO THE HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS HSFAT2/FZNT02 FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AN AXIS THAT EXTENDS FROM 15N40W TO 07N40W...MOVING W AT 15 TO 20 KT. THIS WAVE COINCIDES WITH 700 MB TROUGHING BETWEEN 36W AND 43W. SSMI TPW INDICATES DEEP MOISTURE IS MAINLY CONFINED TO THE SOUTHERN HALF OF THE WAVE. ISOLATED MODERATE CONVECTION IS WITHIN 75 NM OF THE WAVE AXIS S OF 10N. A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AND AXIS THAT EXTENDS FROM 17N53W TO 09N50W...MOVING W AT AROUND 10 KT. THIS WAVE IS AT THE LEADING EDGE OF A SURGE OF DEEP MOISTURE. SUBTLE 700 MB TROUGHING IS INDICATED IN MODEL FIELDS BETWEEN 47W AND 52W. AN UPPER LOW NEAR 21N58W IS INTERACTING WITH THE WAVE...SHEARING MOST CONVECTION OFF TO THE EAST. ISOLATED MODERATE CONVECTION IS FROM 10N TO 15N BETWEEN 45W AND 50W. A TROPICAL WAVE EXTENDS FROM THE SW GULF OF MEXICO NEAR 22N92W TO GUATEMALA TO THE E PACIFIC. THIS WAVE IS INTERACTING AND BEING ABSORBED BY A BROAD MONSOON GYRE CENTERED NEAR 17N89W. DEEP MOISTURE IS IN THE ENVIRONMENT OF THE WAVE. HOWEVER...MOST NEARBY DEEP CONVECTION IS CONFINED TO LAND AREAS AND OVER THE CARIBBEAN...ASSOCIATED WITH THE MONSOON GYRE. THE GYRE IS DISCUSSED BELOW IN THE CARIBBEAN SECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM A 1010 MB LOW NEAR 13N27W TO 07N40W. ISOLATED MODERATE CONVECTION IS NOTED WITHIN 125 NM OF THE MONSOON TROUGH AXIS BETWEEN 33N AND 38N...AND WITHIN 75 NM OF THE CENTER OF THE 1010 MB LOW. ...DISCUSSION... GULF OF MEXICO... A BROAD TROUGH COVERS THE EASTERN US WITH A MID TO UPPER LEVEL SHORTWAVE TROUGH OVER FL. THIS TROUGHING SUPPORTS A COLD FRONT THAT EXTENDS FROM THE W ATLC TO N FL NEAR 30N83W TO 29N90W TO 28N97W. THIS FRONT IS EMBEDDED IN DRY AIR WITH NO CONVECTION. AN ONGOING TIGHT MOISTURE GRADIENT IS ACROSS THE CENTRAL/SOUTHERN GULF IN THE FORM OF A STATIONARY FRONT THAT EXTENDS FROM MIAMI TO 25N87W TO 24N94W. ISOLATED MODERATE CONVECTION IS WITHIN 150 NM S OF THE STATIONARY FRONT. STRONG HIGH PRESSURE IS ACROSS THE UPPER MISSISSIPPI VALLEY HELPING TO SUPPORT MAINLY FRESH NE WINDS N OF THE STATIONARY FRONT. A SURFACE TROUGH EXTENDS OVER THE SW GULF FROM 23N97W TO 19N94W. A MONSOON GYRE WITH A 1008 MB LOW IS CENTERED NEAR 17N89W. A TIGHT PRESSURE GRADIENT BETWEEN THE HIGH OVER THE US AND LOWER PRESSURE ASSOCIATED WITH THE SURFACE TROUGH AND MONSOON GYRE SUPPORTS GALE FORCE WINDS OVER A PORTION OF THE SW GULF. PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS. A TROPICAL WAVE IS ALSO OVER THE SW GULF AND IS BEING ABSORBED INTO THE LARGER CIRCULATION OF THE MONSOON GYRE. PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS. OVER THE NEXT 24 HOURS THE COLD FRONT WILL MERGE WITH THE STATIONARY FRONT OVER THE S CENTRAL GULF. CONVECTION WILL CONTINUE AND INCREASE OVER THE SW GULF NEAR THE SURFACE TROUGH WITH THE MONSOON GYRE LOW DRIFTING NW TOWARD THE SW GULF. GALE FORCE WINDS WILL CONTINUE OVER A PORTION OF THE SW GULF AS WELL. FRESH TO OCCASIONALLY STRONG E TO NE WINDS WILL PERSIST ACROSS MUCH OF THE REMAINDER OF THE GULF N OF THE COLD FRONT THROUGH SUNDAY. CARIBBEAN SEA... A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION INFLUENCES MUCH OF THE WESTERN CARIBBEAN AND CENTRAL AMERICA...PROVIDING AN OVERALL DIFFLUENT ENVIRONMENT ALOFT. AN AREA OF LOW PRESSURE OF 1008 MB IS CENTERED NEAR 17N89W...AND IS ASSOCIATED WITH A BROAD MONSOON GYRE CIRCULATION THAT COVERS A LARGE PORTION OF CENTRAL AMERICA. THIS CIRCULATION SUPPORTS SCATTERED MODERATE CONVECTION FROM 16N TO 21N BETWEEN 82W AND 90W...AND FROM 09N TO 15N W OF 78W. DRIER AIR AND SUBSIDENCE SUPPORTS GENERALLY FAIR WEATHER E OF 78W ACROSS THE CENTRAL AND EASTERN CARIBBEAN. MAINLY MODERATE TRADE WINDS COVER THE CENTRAL AND EASTERN CARIBBEAN WITH MODERATE TO FRESH TRADES OVER THE WESTERN CARIBBEAN. OVER THE NEXT 24 HOURS CONVECTION WILL CONTINUE OVER THE W CARIBBEAN ASSOCIATED WITH THE MONSOON GYRE LOW. ...HISPANIOLA... NW TO N WINDS ALOFT PERSIST ACROSS HISPANIOLA BETWEEN AN UPPER ANTICYCLONE TO THE WEST AND AN UPPER LEVEL TROUGH TO THE EAST. MODERATE MOISTURE IS IN PLACE...FAVORING LOW TOPPED AND FAST MOVING SHOWERS AND THUNDERSTORMS PRIMARILY OVER THE HIGHLAND PORTIONS OF WESTERN DOMINICAN REPUBLIC AND EASTERN HAITI DURING THE AFTERNOON AND EVENING HOURS OVER THE NEXT COUPLE OF DAYS. ATLANTIC OCEAN... A STATIONARY FRONT REMAINS IN PLACE FROM BERMUDA TO THE NW BAHAMAS AND FORMS THE BOUNDARY BETWEEN DEEP LAYER MOISTURE TO THE SOUTH AND A DRIER AIRMASS OVER THE WATERS BETWEEN NE FLORIDA AND BERMUDA. SCATTERED SHOWERS AND THUNDERSTORMS ARE NOTED WITHIN 275 NM TO THE SOUTH OF THE STATIONARY FRONT. A COLD FRONT WILL ENTER OUR AREA OF DISCUSSION OFF THE SE US COAST TODAY AND WILL MERGE WITH THE STATIONARY FRONT TONIGHT. FARTHER EAST...A SURFACE TROUGH EXTENDS N OF A TROPICAL WAVE FROM 21N54W TO 17N53W AND IS INTERACTING WITH AN UPPER LOW CENTERED NEAR 21N58W. ISOLATED MODERATE CONVECTION IS WITHIN 300 NM E OF THE SURFACE TROUGH. SCATTERED MODERATE CONVECTION IS FROM 17N TO 25N BETWEEN 56W AND 61W. THE EASTERN SUBTROPICAL ATLC IS DOMINATED BY A COLD FRONT THAT EXTENDS FROM THE COAST OF AFRICA NEAR 12N16W TO 21N19W...WHERE IT TRANSITIONS TO A DISSIPATING COLD FRONT TO 16N34W...TO A SHEAR LINE THAT EXTENDS TO 21N50W. NO DEEP CONVECTION IS NOTED. OVER THE NEXT 24 HOURS SCATTERED THUNDERSTORMS WILL CONTINUE S OF THE STATIONARY FRONT AS THE COLD FRONT MERGES WITH IT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO