Sub-Cloud Layer Kinematics and Convective Rainfall in Central Illinois.
ILLINOIS STATE WATER SURVEY DIV URBANA
Pagination or Media Count:
The kinematic parameters of divergence and vorticity in the lowest 450 m of the atmosphere were calculated ofr a 750 km area in east central Illinois form wind measurements obtained using pilot balloons. The area for which the analysis has been made is triangular, west of ChampaignUrbana. These and similar data for the surface have been analyzed for nine days of the summer of 1979. Most of the observations were made during the afternoon and early evening hours during periods when tropical air masses overlay the observational network. The maximum surface temperatures on these days ranged from 26.5 to 35 C, and the surface dew-point temperatures varied from 18 to 24 C, approximately normal for temperature but more humid then normal. The average dew-point for central Illinois is 18 C during July, 17 C in August. The precipitable water content from the surface to 400 mb ranged from 3.2 to 5.3 cm, higher by as much as 77 at the extreme than the normal precipitable water over central Illinois during July or August Lott, 1976. Author