There were 12 convective periods for May 1999:
Start: 07/01Z End: 07/05Z Flow Regime: SW-2    radar/wind loop
Start: 08/17Z End: 09/01Z Flow Regime: SW-2    radar/wind loop
Start: 09/17Z End: 10/02Z Flow Regime: SW-2    radar/wind loop
Start: 12/19Z End: 13/02Z Flow Regime: SW-2    radar/wind loop
Start: 19/22Z End: 20/00Z Flow Regime: Other   radar/wind loop
Start: 21/02Z End: 21/08Z Flow Regime: Other   radar/wind loop
Start: 25/23Z End: 26/03Z Flow Regime: SW-2    radar/wind loop
Start: 27/17Z End: 28/01Z Flow Regime: NW      radar/wind loop
Start: 28/14Z End: 28/19Z Flow Regime: SW-2    radar/wind loop
Start: 29/07Z End: 29/13Z Flow Regime: NW      radar/wind loop
Start: 30/00Z End: 30/21Z Flow Regime: NW      radar/wind loop
Start: 31/20Z End: 01/04Z Flow Regime: NE      Continued into June   radar/wind loop
 
Start: 07/01Z End: 07/05Z Flow Regime: SW-2    radar/wind loop
 First peak wind >= 20 knots at 070100Z   Last at 070445Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 32 knots from 145 degrees for tower 0061 at 204 feet on 070335Z
 
Start: 08/17Z End: 09/01Z Flow Regime: SW-2    radar/wind loop
 First peak wind >= 20 knots at 081945Z   Last at 082355Z
 First peak wind >= 35 knots at 082015Z   Last at 082150Z
 First peak wind >= 50 knots at 082100Z   Last at 082110Z
 Max peak wind reported was 61 knots from 223 degrees for tower 0311 at 054 feet on 082105Z
 
Start: 09/17Z End: 10/02Z Flow Regime: SW-2    radar/wind loop
 First peak wind >= 20 knots at 091910Z   Last at 100135Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 30 knots from 239 degrees for tower 0021 at 204 feet on 092055Z
 
Start: 12/19Z End: 13/02Z Flow Regime: SW-2    radar/wind loop
 First peak wind >= 20 knots at 122030Z   Last at 122345Z
 First peak wind >= 35 knots at 122255Z   Last at 122305Z
 No peak winds >= 50 knots were reported
 Max peak wind reported was 42 knots from 242 degrees for tower 0022 at 054 feet on 122305Z
 
Start: 19/22Z End: 20/00Z Flow Regime: Other   radar/wind loop
 First peak wind >= 20 knots at 192240Z   Last at 192325Z
 First peak wind >= 35 knots at 192300Z   Last at 192300Z
 No peak winds >= 50 knots were reported
 Max peak wind reported was 37 knots from 265 degrees for tower 0421 at 054 feet on 192300Z
 
Start: 21/02Z End: 21/08Z Flow Regime: Other   radar/wind loop
 First peak wind >= 20 knots at 210310Z   Last at 210450Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 25 knots from 194 degrees for tower 1000 at 054 feet on 210355Z
 
Start: 25/23Z End: 26/03Z Flow Regime: SW-2    radar/wind loop
 First peak wind >= 20 knots at 252300Z   Last at 260220Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 24 knots from 165 degrees for tower 3131 at 295 feet on 260005Z
 
Start: 27/17Z End: 28/01Z Flow Regime: NW      radar/wind loop
 First peak wind >= 20 knots at 271740Z   Last at 272220Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 25 knots from 170 degrees for tower 1000 at 054 feet on 272035Z
 
Start: 28/14Z End: 28/19Z 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 17 knots from 082 degrees for tower 3132 at 204 feet on 281635Z
 
Start: 29/07Z End: 29/13Z Flow Regime: NW      radar/wind loop
 First peak wind >= 20 knots at 290800Z   Last at 291205Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 27 knots from 034 degrees for tower 0061 at 204 feet on 291120Z
 
Start: 30/00Z End: 30/21Z Flow Regime: NW      radar/wind loop
 First peak wind >= 20 knots at 300005Z   Last at 302100Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 26 knots from 081 degrees for tower 0061 at 162 feet on 300255Z
 
Start: 31/20Z End: 01/04Z Flow Regime: NE      Continued into June   radar/wind loop
 First peak wind >= 20 knots at 312200Z   Last at 312355Z
 No peak winds >= 35 knots were reported
 No peak winds >= 50 knots were reported
 Max peak wind reported was 27 knots from 095 degrees for tower 1007 at 054 feet on 312355Z