Synthesis for May 22, 2001

Summary for May 22, 2001

Investigator: (Jim Dye)

NOTE: The Electric Field measurements were extremely noisy and unuseable from ~2158 to 2225 and briefly from 2309 to ~2311. They are not shown on MER or E field plots currently on the Web.

The Citation took off at 2128 and flew to an area of weak, but organized convection about 50 km to the SE of PAFB. This band of convection was moving from the WSW to ENE at 15 to 20 m/s and had been producing lightning for at least the last 2 hours. New, stronger cells tended to form on the NW end of this band. The convection was stratiform in character with several cells of embedded convection. The highest reflectivity was at 4 km, decreasing at 7 and then again at 10 km. Radar tops on the cells were 12 to 13 km.
For an example go to:



During this period and for approximately the next hour the Citation flew near the top of the 20 dBZ radar return.



For times with electric field data available (before 2158 and after 2225) the Emag had values up to 30 to 40 kV/m. After about 2300 the E field seems to be weakening.

DOES this qualify as a thick cloud case?

Although lightning continued to occur 50 km or more away on the NW end of this band, the last CG flash in the region in which the A/C flew occurred at ~2145 (See previous CAPPI) and the last LDAR sources at ~2150. The Citation continued to go back and forth through pretty much the same area of convection until ~2350 as it drifted to the NE. During this period the electric fields gradually decreased so that they were < 3 kV/m by the time the Citation left.



SUMMARY: The Citation following a band of stratiform convection as convection and reflectivity decayed. The electric fields decayed from ~40 kV/m to <3 kV/m

The scatter plot for both 5 and 10 km boxes both have no points within the zone of >5 dBZ and E field > 3kV/m.