The 1 August 1981 MOPE Storm: Observations and Modeling Results

Abstract

Observations made by the T-28 armored research aircraft, radar, and other data sources were used to study an eastern Moutana hailstorm that developed on 1 August 1981 during the Cooperative Convective Precipitation Experiment season. The storm featured a wide, persistent, vertically oriented updraft with speeds exceeding 35 m s?1. Hailstones of over 5 cm diameter were collected at the ground, while the T-28 encountered hail up to about 2.5 cm diameter. Them was no evidence of feeder cells or a weak echo region. The IAS two-dimensional, time-dependent ?bulk water? model was run on this case, using a sounding from this day. Some areas of agreement between the simulation and observations include the maximum updraft speed, cloud top height, presence of a rounded cloud dome, and maximum radar reflectivity. The simulation failed to properly model the width and orientation of the updraft, as well as its long lifetime. The IAS hail category model was also run on this case. This model features 20 categories of ice particles, which aid in exploring the complexities of hailstone growth. This simulation was dynamically similar to the bulk water simulation. The model predictions of ice particle concentrations agreed fairly well with those observed, and the shedding of drops during the wet growth of had was a significant source of had embryos.