May 23 - July 29
Comparison of Estimated and Observed Storm Motions to Environmental Parameters
Eric Beamesderfer, Kiel Ortega, Travis Smith, and John Cintineo
What is already known:
- Storm motion estimates are either storm type specific or are inaccurate due to the fact they are determined by the kinematic field only.
- Numerical modelling studies show that thermodynamic variables are also important to storm motion, yet no work has been completed with observations.
What this study adds:
- Overall, all motion estimators are fairly inaccurate.
- Investigated thermodynamic variables did not reveal additional information about storm motion estimate errors.
- Storm relative helicity, a variable derived from the kinematic field, showed the most influence on storm motion estimate errors. However, helicity values are closely related to storm mode (i.e., supercell vs. non-supercell) thus storm mode may be more important than specific environmental variables.
Abstract:
This study explores current storm motion techniques and analyzes their accuracy with respect to different environmental parameters. Current motion estimates are compared to observed motions and different environmental parameters. The parameters investigated are the heights of the lifted condensation level (LCL) and the level of free convection (LFC), the mean relative humidity from the surface to 0°C and the storm relative helicity (SRH) from 0-3 km. Deviate estimates were seen by each storm motion estimator for the different environmental parameters. Also, it was evident that some storm motion estimators were superior to others. However, overall the observed motions in this study were dissimilar to the environmental.