000 AXNT20 KNHC 102353 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED OCT 10 2012 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 FEATURE... TROPICAL WAVE IS EAST OF THE LESSER ANTILLES ALONG 17N53W TO A 1008 MB SURFACE LOW AT 9N54W. THE SYSTEM IS EXPECTED TO MOVE W-NW AT ABOUT 10 KT. THE WAVE LIES WITHIN A LARGE AREA OF ENHANCED DEEP LAYER MOISTURE RANGING FROM 8N16N BETWEEN 47W-60W. BROAD LOW-LEVEL CIRCULATION IS ALSO AROUND THE WAVE IN THIS AREA. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 7N-17N BETWEEN 44W-60W. GUSTY WINDS AND HEAVY RAINFALL ARE POSSIBLE OVER THE LESSER ANTILLES AS THE SYSTEM MOVES CLOSER TO THE ISLANDS. SOME GRADUAL DEVELOPMENT OF THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS THROUGH WEST AFRICA TO THE COAST OF GUINEA NEAR 11N15W CONTINUING OVER ATLC WATERS ALONG 5N19W 5N32W. THE ITCZ BEGINS AT 5N32W AND CONTINUES TO 6N44W. NO DEEP CONVECTION IS ASSOCIATED WITH THE ITCZ/MONSOON TROUGH AT THIS TIME. ...DISCUSSION... THE GULF OF MEXICO... WEAK SURFACE RIDGING WITH LIGHT ANTI-CYCLONIC SURFACE FLOW IS ACROSS THE GULF OF MEXICO EXTENDING FROM A HIGH CENTER OVER MISSOURI. MOSTLY FAIR WEATHER IS IMPACTING THE BASIN DUE TO DRY AIR ALOFT AROUND A BROAD UPPER LEVEL TROUGH COVERING THE EASTERN CONUS. HOWEVER...BOTH THE NW AND SE GULF ARE EXPERIENCING SOME SHOWERS/THUNDERSTORMS AT THIS TIME. IN THE NW GULF...SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 26N-29N BETWEEN 92W-97W. THIS ACTIVITY IS LIKELY TIED TO A SMALL MID-LEVEL TROUGH OVER SOUTHERN TEXAS. ISOLATED SHOWERS/THUNDERSTORMS ARE IN THE SE GULF S OF 26N E OF 88W. THIS IS LINKED TO WEAK DIFFLUENCE AROUND THE EAST SIDE OF THE UPPER TROUGH AXIS WHICH EXTENDS INTO THE GULF ALONG 88W. SURFACE RIDGING IS EXPECTED TO REMAIN OVER THE BASIN FOR THE NEXT COUPLE OF DAYS. THE CARIBBEAN SEA... AN UPPER LEVEL RIDGE COVERS THE NW CARIBBEAN TONIGHT WITH AXIS EXTENDING FROM CENTRAL CUBA TO GUATEMALA AND CONTINUING INTO MEXICO. AN UPPER LEVEL TROUGH OVER THE GULF OF MEXICO IS HELPING PROVIDE DIFFLUENT FLOW OVER PORTIONS OF THE NW CARIBBEAN PRODUCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER WESTERN CUBA WITH ISOLATED SHOWERS FROM 17N-20N BETWEEN 82W-88W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO ACROSS A GOOD PORTIONS OF HONDURAS AND NICARAGUA AND CONTINUING OFFSHORE TO 82W. SIMILAR ACTIVITY IS ACROSS COSTA RICA AND PANAMA AND THE AREA S OF 12N W OF 79W ASSOCIATED WITH THE E PACIFIC MONSOON TROUGH EXTENDING THROUGH BOTH COSTA RICA AND PANAMA TO NORTHERN COLOMBIA. THE REMAINDER OF THE BASIN IS EXPERIENCING MOSTLY FAIR WEATHER DUE TO DRY AIR ALOFT AROUND A NARROW UPPER TROUGH EXTENDING FROM THE CENTRAL ATLC INTO THE EASTERN CARIBBEAN TO NORTHERN VENEZUELA. TRADEWIND FLOW OF 10-15 KT IS ACROSS MUCH OF THE AREA WITH A FEW STRONGER WINDS NORTH OF COLOMBIA. ISOLATED LOW-LEVEL SHOWERS ARE EMBEDDED WITH IN THE EASTERLY FLOW. A TROPICAL WAVE EAST OF THE LESSER ANTILLES IS EXPECTED TO BRING GUSTY WINDS AND HEAVY RAINFALL TO PORTIONS OF THE ISLANDS OVER THE NEXT COUPLE OF DAYS. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS ON THE WAVE. THE ATLANTIC OCEAN... A BROAD UPPER TROUGH COVERING THE EASTERN CONUS CONTINUES OVER THE FAR WESTERN ATLC ALONG WITH DRY AIR PROVIDING FAIR CONDITIONS ACROSS THE W ATLC W OF 76W. TO THE EAST...A 1013 MB SURFACE LOW IS NORTH OF THE SE BAHAMAS CENTERED NEAR 26N72W WITH A SURFACE TROUGH EXTENDING TO THE NORTH TO 31N72W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE MAINLY EAST OF THE LOW CENTER FROM 22N-28N BETWEEN 70W-72W. SIMILAR ACTIVITY IS WITHIN 120 NM EAST OF THE TROUGH AXIS. FAIR CONDITIONS COVER THE REMAINDER OF THE WEST ATLC DUE TO DRY AIR ALOFT AROUND THE EAST SIDE OF AN UPPER LEVEL RIDGE EXTENDING FROM THE NW CARIBBEAN ACROSS CENTRAL CUBA TO NEAR 38N46W. A NARROW UPPER LEVEL TROUGH IS TO THE EAST OF THE RIDGE EXTENDING FROM EAST OF THE AZORES ISLANDS NEAR 36N20W CONTINUING ALONG 27N34W 25N54W TO THE EASTERN CARIBBEAN AT 18N63W. DIFFLUENCE ALOFT AROUND THE EAST SIDE OF THE UPPER TROUGH IS HELPING SUPPORT SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 21N-24N BETWEEN 44W-56W. A BROAD SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED NEAR 36N41W IS PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE REMAINDER OF THE CENTRAL AND EASTERN ATLC SUPPORTED BY AN UPPER LEVEL RIDGE NORTH OF THE DISCUSSION AREA. UPPER LEVEL RIDGING ALSO COVERS THE TROPICAL ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON