There were 8 convective periods for September 1999:
Start: 06/14Z End: 06/21Z Flow Regime: SW-1    radar/wind loop
Start: 08/15Z End: 08/21Z Flow Regime: Other   radar/wind loop
Start: 10/00Z End: 10/05Z Flow Regime: SW-2    radar/wind loop
Start: 10/19Z End: 11/10Z Flow Regime: SW-2    radar/wind loop
Start: 13/17Z End: 14/04Z Flow Regime: NE      radar/wind loop
Start: 18/02Z End: 18/10Z Flow Regime: SE-2    radar/wind loop
Start: 23/21Z End: 24/05Z Flow Regime: SE-1    radar/wind loop
Start: 29/14Z End: 29/20Z Flow Regime: SE-1    radar/wind loop
 
Start: 06/14Z End: 06/21Z Flow Regime: SW-1    radar/wind loop
 First peak wind >= 20 knots at 061455Z   Last at 062020Z
 First peak wind >= 35 knots at 061525Z   Last at 061950Z
 First peak wind >= 50 knots at 061945Z   Last at 061945Z
 Max peak wind reported was 58 knots from 202 degrees for tower 0001 at 054 feet on 061945Z
 
Start: 08/15Z End: 08/21Z Flow Regime: Other   radar/wind loop
 First peak wind >= 20 knots at 081840Z   Last at 082000Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 27 knots from 332 degrees for tower 1007 at 054 feet on 081855Z
 
Start: 10/00Z End: 10/05Z Flow Regime: SW-2    radar/wind loop
 First peak wind >= 20 knots at 100200Z   Last at 100335Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 34 knots from 357 degrees for tower 0300 at 054 feet on 100320Z
 
Start: 10/19Z End: 11/10Z Flow Regime: SW-2    radar/wind loop
 No peak winds >= 20 knots were reported
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 18 knots from 006 degrees for tower 0019 at 054 feet on 110610Z
 
Start: 13/17Z End: 14/04Z Flow Regime: NE      radar/wind loop
 First peak wind >= 20 knots at 131700Z   Last at 140400Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 33 knots from 035 degrees for tower 0061 at 204 feet on 140020Z
 
Start: 18/02Z End: 18/10Z Flow Regime: SE-2    radar/wind loop
 First peak wind >= 20 knots at 180500Z   Last at 180940Z
 First peak wind >= 35 knots at 180615Z   Last at 180615Z
 No peak winds >= 50 knots were reported
 Max peak wind reported was 41 knots from 125 degrees for tower 0211 at 054 feet on 180615Z
 
Start: 23/21Z End: 24/05Z Flow Regime: SE-1    radar/wind loop
 First peak wind >= 20 knots at 232215Z   Last at 240215Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 34 knots from 191 degrees for tower 1007 at 054 feet on 240020Z
 
Start: 29/14Z End: 29/20Z Flow Regime: SE-1    radar/wind loop
 First peak wind >= 20 knots at 291745Z   Last at 291755Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 24 knots from 304 degrees for tower 0412 at 054 feet on 291755Z