A New Method for Calculating Vertical Motion in Isentropic Space

A full isentropic vertical motion (ωθ) has long been difficult to calculate in an operational forecasting environment (Market et al. 2002). However, recent interactions with the Springfield, MO (SGF) National Weather Service Office spurred the development of the current method of estimating the total ωθ. During the winter of 2012-13, this expression was developed into its current form, and initial tests were undertaken to test its usefulness. Using output from NCEP's operational NAM-WRF model, individual points were evaluated for isentropic surfaces with condensation pressure differences < 20 mb and regions beneath where model precipitation occurred. The results of these initial trials are detailed in the present work. Broader trials are currently underway. The ensuing work will address fields of ω values over large areas, compared statistically to the fields from dynamically consistent numerical model solutions. These results will be presented at a later date.