Weaver, Dostalek, Grasso, Bikos, Motta

GOES-10 assessment data from the 08 Apr 98, Birmingham, Alabama tornado case is proving to be an excellent data set for helping to understand the environment preceding southeastern U.S. tornadoes.  In particular, the low-level broken-to-overcast sky coverage that we thought might mask important low-level boundaries, may actually reveal previously undefined features associated with the evolution of the boundary layer.  In the case of 08 Apr 98, for example, we find two cloud lines which seem to mark fairly large-scale convergence zones.  The origin(s) of these convergence zones, and their  role(s) in the convective cycle, is not yet fully understood.  Research continues.
 

GOES-10 visible image from 2150 UTC on 08Apr98 showing two of the convergence lines that appeared to play important roles in the development of severe convection.  The southernmost line formed along a cloudy versus clear boundary.  (Click on image to enlarge)

Reviewer's comments have been received from National Weather Digest for the 31 May 1996 Kansas and Colorado severe weather case study.  The results were favorable, both reviewers having accepted the manuscript with minor revisions.   Questions/concerns will be addressed and the article sent back for publication.  An electronic version of portions of this case (called "Detecting low-level thunderstorm Outflow boundaries using GOES at night") can be viewed at --  http://www.cira.colostate.edu/ramm/visit/lto.html

GOES-8 SRSO imagery and WSR-88D data from 17 May 1996 have been synthesized and show that the development of a long-lived left moving storm was triggered by an expanding low-level thunderstorm outflow boundary interacting with a pre-existing convergence line.  Historical numerical modeling evidence suggests that left moving updrafts develop from the "classic" storm splitting process. This study hopes to show that, at times, left movers might develop by another process. A "note" to Weather and Forecasting is being prepared.