000 AXNT20 KNHC 161806 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED OCT 16 2013 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. ...TROPICAL WAVES... TROPICAL WAVE AXIS EXTENDS FROM 11N34W TO 03N36W AND MOVES W NEAR 10 KT. THE WAVE IS EMBEDDED WITHIN THE ITCZ AXIS AS WELL AS IN A REGION OF HIGH TO MAXIMUM MOISTURE IN THE SSMI TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION IS FROM 03N-08N BETWEEN 32W-38W. TROPICAL WAVE AXIS EXTENDS FROM 17N44W TO 09N50W AND MOVES W-NW NEAR 5 KT. SSMI TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS MOSTLY EMBEDDED WITHIN A MODERATE MOIST ENVIRONMENT. MOIST UPPER-LEVEL SOUTHWESTERLY DIFFLUENT FLOW DEPICTED IN WATER VAPOR IMAGERY IS SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS ARE FROM 10N-16N BETWEEN 40W-54W. TROPICAL WAVE AXIS PREVIOUSLY OVER CENTRAL AMERICA HAS MOVED TO THE EAST PACIFIC. ITS AXIS EXTENDS FROM 14N90W TO 08N87W AND IS MOVING W NEAR 15-20 KT. SMI TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS EMBEDDED WITHIN A VERY MOIST ENVIRONMENT. MIDDLE-LEVEL DIFFLUENCE IS SUPPORTING SCATTERED MODERATE CONVECTION FROM 09N-13N BETWEEN 87W-92W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO 06N17W TO 06N21W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N21W TO 08N32W...THEN CONTINUES WEST OF A TROPICAL WAVE NEAR 06N38W TO 08N47W...THEN CONTINUES WEST OF A SECOND TROPICAL WAVE NEAR 09N52W TO GUYANA NEAR 07N59W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS FROM 04N-10N EAST OF 18W. SIMILAR CONVECTION IS WITHIN 200 NM NORTH AND 100 NM SOUTH OF THE ITCZ AXIS BETWEEN 38W-48W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE GULF NEAR 24N90W AND IS PROVIDING THE BASIN WITH GENERALLY DRY AND STABLE FLOW ALOFT. THIS STABILITY REFLECTS TO THE SURFACE AS A RIDGE REMAINS IN PLACE EXTENDING SW FROM THE SE CONUS WITH LIGHT ANTICYCLONIC WINDS IN THE RANGE OF 5 TO 10 KT ACROSS THE BASIN. A WEAK SURFACE TROUGH IS ON THE NE GULF EXTENDING FROM 29N86W TO 26N84W WITH NO CONVECTION ASSOCIATED WITH IT. AN UPPER-LEVEL TROUGH EXTENDING FROM NORTHERN MICHIGAN LAKE SW TO THE CENTRAL ROCKIES IS SUPPORTING A FRONTAL SYSTEM THAT ENTERS THE FAR NW GULF AS A COLD FRONT. THE COLD FRONT EXTENDS FROM SW LOUISIANA NEAR 29N93W SW TO SOUTHERN TEXAS NEAR 27N97W. ISOLATED SHOWERS ARE SHOWN IN RADAR IMAGERY N OF 26N W OF 91W. THE FRONT WILL CONTINUE TO DRIFT E-SE THROUGH THURSDAY NIGHT AND THEN IS FORECAST TO BECOME STATIONARY ACROSS THE NE AND AND NW GULF. CARIBBEAN SEA... A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM THE SW NORTH ATLC REGION TO HISPANIOLA TO THE SOUTHERN-CENTRAL BASIN. THIS MIDDLE TO UPPER LEVEL FEATURE SUPPORTS A SURFACE TROUGH THAT AT 1500 UTC EXTENDS FROM 24N69W TO THE WINDWARD PASSAGE NEAR 19N73W TO 17N77W. SCATTERED MODERATE CONVECTION IS WITHIN 50 NM EITHER SIDE OF THE AXIS FROM 16N-19N. WEST OF THE MIDDLE TO UPPER LEVEL TROUGH AXIS...NORTHERLY FLOW FROM THE BROAD RIDGE OVER THE GULF IS ADVECTING DRY AIR TO THE NW GULF N OF 15N W OF 79W WHICH IS SUPPRESSING ANY SIGNIFICANT CONVECTION AT THIS TIME. FURTHER EAST...DIFFLUENT FLOW ALOFT IS SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE CENTRAL BASIN S OF 15N BETWEEN 69W-75W. SIMILAR CONVECTION IS OVER THE SOUTHERN CARIBBEAN S OF 15N WHICH IS ASSOCIATED WITH THE MONSOON TROUGH AXIS THAT EXTENDS FROM NORTHERN COSTA RICA TO NORTHERN COLOMBIA. A SURFACE TROUGH IS FORECAST TO MOVE ACROSS THE LEEWARD ISLANDS EARLY ON FRIDAY WHICH IS EXPECTED TO DISSIPATE IN THE EVENING HOURS. ISOLATED SHOWERS IS LIKELY FOR THE NE BASIN. HISPANIOLA... A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM THE SW NORTH ATLC REGION TO HISPANIOLA TO THE SOUTHERN-CENTRAL CARIBBEAN. THIS MIDDLE TO UPPER LEVEL FEATURE SUPPORTS A SURFACE TROUGH THAT AT 1500 UTC EXTENDS FROM 24N69W TO THE WINDWARD PASSAGE NEAR 19N73W TO 17N77W. CURRENTLY...THIS INSTABILITY IN THE ATMOSPHERE IS PRODUCING ISOLATED SHOWERS ACROSS THE ISLAND. HOWEVER...AS THE THE MIDDLE TO UPPER LEVEL TROUGHING CONTINUES TO DRIFT EASTWARD CONVECTIVE ACTIVITY MAY DEVELOP LATER THIS AFTERNOON. SCATTERED MODERATE CONVECTION IS SW OF THE SOUTHERN COASTLINE OF HAITI WITHIN 50 NM EITHER SIDE OF THE SURFACE TROUGH AXIS FROM 16N-19N. SHOWER AND TSTMS ACTIVITY IS EXPECTED THROUGH FRIDAY. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL TROUGH AXIS IN THE SW NORTH ATLC NEAR 70W IS SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 22N67W TO 27N66W TO 29N69W. SCATTERED MODERATE CONVECTION AND TSTMS ARE WITHIN 350 NM EAST OF THE AXIS. IT ALSO SUPPORTS ANOTHER SURFACE TROUGH THAT EXTENDS FROM 24N69W TO THE WINDWARD PASSAGE NEAR 19N73W TO 17N77W. SCATTERED MODERATE CONVECTION AND TSTMS ARE FROM 20N-25N BETWEEN 68W-73W...INCLUDING THE SOUTHERN BAHAMAS. A WEAK SURFACE TROUGH IS NE OF THE LEEWARD ISLANDS EXTENDING FROM 21N59W TO 16N56W WITH NO CONVECTION ASSOCIATED WITH IT. OTHERWISE...AN UPPER-LEVEL TROUGH IN THE CENTRAL N ATLC SUPPORTS A FRONTAL SYSTEM THAT ENTERS THE AREA OF DISCUSSION AS A COLD FRONT NEAR 30N34W SW TO 27N45W WHERE IT TRANSITIONS TO A STATIONARY FRONT TO 30N55W. SCATTERED SHOWERS ARE N OF 26N BETWEEN 32W-53W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR