Minutes for 13 December Conference Call…
1. Call began at 1 PM. Attendees are…
GSP…Pat Moore, Justin Lane, Larry Lee
CAE…Mike Cammarata, Hunter Coleman, Shawn Smith
RAH…Mike Strickler, Jonathan Blaes
[Please let me know if you were on the call but are not on this list. -pat]
2. Reflection upon the 30 November-1 December event and other recent events generated much discussion among the attendees with several excellent insights and opinions shared. One common theme running through the discussion included a need for a better understanding of the near-storm environment around HSLC storms. NWS forecasters have situational awareness of the HSLC environment in general, although sometimes the onset of the event could be anticipated better, which is a concern because of the impact on staffing. NWS forecasters more often lack enough understanding of the near storm environment to differentiate between which storms will produce severe weather (tornadoes) and which will not. Another common theme was the need for better conceptual models of HSLC storms that forecasters could consistently use when evaluating radar signatures during HSLC storm events.
During the discussion, Steve Zubrick indicated that HSLC storms are receiving some attention up in the highest levels of NWS management because of the 17 November Baltimore tornado. He will be making a presentation at NWSHQ concerning the event. He has been in contact with Steve Weiss about the event and indicated that Steve W. might have some interesting severe weather-tornado climatology to share with the group.
3. There was some discussion about Dr. Parker’s vision for CI participation and how that might relate to the work that a Master’s Degree student would perform. The long-range goal of the case studies is to provide a more granular view of what is happening in events and nulls, in order to complement a more longitudinal study of gross statistics that will be undertaken by a M.S. student at NCSU. The longitudinal study will include a large database of environments and a large database of convective modes, but will not address the messy details that are obviously present in individual cases. In a sense, the case studies represent the bridge between the “ingredients-based” forecasting/nowcasting perspective and the “boots on the ground reality” of how these cases unfold and are treated from a WFO perspective.
The case studies should focus on the 0-3 hr time frame from the mesoscale (near storm environment, boundaries, convective parameters) down to the convective scale (radar signatures and warning/no warning decisions), including verification. As such, the case studies would be observationally oriented.
4. Most of the discussion specifically about case studies revolved around what constituted an event vs. what was a “null.” It was generally agreed that null events are difficult to quantify and that on a particular day, one office might experience an event while a neighboring office might not have any events, so an event for one office might be a null for another. [Additional post-call discussion will be conducted as a reply to this blog entry. –pat]
A consensus was reached that thresholds for HSLC environments would be a CAPE of less than roughly 500 J kg-1, and 0-6km shear of at least 35 kt (it was noted that 0-3km shear of at least 30 kt might be better, but this is not routinely available in SPC mesoanalyses). [Brief discussion post-call indicated the threshold should be on SBCAPE as a starting point. –pat]
Important things to include in a case study would include a representative sounding and appropriate radar data. SPC mesoscale analysis graphics for sector 17 are archived at NWS Raleigh.
5. As for how we get started, case selection is job one. It was agreed that the easiest way to get started would be to identify severe weather events from Storm Data, in spite of its inherent biases, and then to determine which of those events were produced in HSLC environments. [post-call discussion reminded the note-taker that CIs should not limit their search only to tornadic activity. We should also look for significant wind damage as well. –pat] This strategy will not be able to identify nulls. However, as a first cut it is too labor-intensive to interrogate archived radar data to find nulls. The work of the NCSU M.S. student may provide an objective way to churn through the data sometime down the road.
It was decided we should plan for another call after the Holidays. Matt Parker indicated that mornings would be better for him, but he had no preference for day of month or day of week.
We would like to set up a routine monthly call. Matt will start another poll on Doodle after the New Year to identify a time and day of the week/month to have the routine call.
In the mean time, CIs at the offices can begin the process of identifying events. The main investigators at each office are…
Sterling… Matthew Kramar
Wakefield… Andrew Zimmerman
Blacksburg… Steve Keighton
Raleigh… Mike Strickler
Charleston… Frank Alsheimer
Columbia… Hunter Coleman
Peachtree City…Steve Nelson, Trisha Palmer
Greenville-Spartanburg…Pat Moore, Justin Lane
We are not sure of the involvement of the Morehead City or Wilmington NWS offices, or if there are other offices that want to participate. Jonathan Blaes will contact MHX and ILM to find out if they are going to participate.
Matt Parker…send out Doodle poll after 1 January to determine best time for next call
Jonathan Blaes…contact NWS Morehead City and Wilmington to identify participants, if any
Steve Zubrick…contact Steve Weiss to find out if he could make a presentation (Webinar) for the group about some of his recent work.
Pat Moore…post minutes of call to blog.