June 29, 2016 Meeting

The sixth meeting of the 2015-2016 year took place at the National Weather Service office in Jackson. Our guest speaker was Dr. Todd Murphy of the University of Louisiana-Monroe.

Meeting Minutes

Call to Order
The sixth meeting of the 2015-2016 year took place on Tuesday, June 29th at the National Weather Service office in Jackson, MS. This was a lunch meeting and it was called to order at noon by NWA Chapter President Eric Carpenter.

NWA Recording Secretary Joanne Culin made a list of those in attendance. 12 people attended.

Minutes Approval
Minutes from the April meeting were summarized by Recording Secretary Joanne Culin.

New Business
Treasurer David Cox provided the treasury report. The amount in the treasury was $91.50 as of the start of the meeting. Dues of $50 were collected from two regular members and a student member. A total of $31 was spent for the pizza lunch. The net balance at the end of the meeting was $110.50. This does not reflect $20 dues given by one member in advance for next year.

After discussing potential topics for future meetings, NWA President Eric Carpenter introduced our special guest presenter, Dr. Todd Murphy, Assistant Professor of Atmospheric Science from the University of Louisiana at Monroe (ULM). Dr. Murphy presented his experiences with the first year of The Verification of Origins of Rotation in Tornadoes Experiment (VORTEX-SE), and he discussed what might be upcoming for the second year. He finished his talk with an update on the new radar and other equipment in the Atmospheric Science program at ULM.

Dr. Murphy explained that VORTEX-SE is a congressionally mandated experiment between numerous government agencies and academic institutions. The goals of the experiment are to 1) better understand severe weather and tornado environments, especially in the SE US, 2) understand how NWS forecasters, anticipate, detect, and warn for tornadoes, and 3) understand how the public receive and respond to that information. The domain covered portions of northern Alabama and southern Tennessee, and the team used a variety of mobile and fixed equipment radars, sounding systems, lightning sensors, and other mobile sensing instrumentation to collect the observations. Their home base was at the University of Alabama Huntsville SWIRLL Operations Center.

Dr. Murphy and his students launched weather balloons for remote radiosonde observations and sounding data. Their emphasis was on the following topics:
● Boundary layer heterogeneity
● Airmass recovery and evolution
● Buildup of CAPE and shear
● Evolution of QLCS circulations
● Impacts of land surface on tornado intensity
● Improving model forecasts

The data were collected during four Intensive Operation Periods (IOPs) (3/12, 3/24, 3/31-4/1, 4/27-5/1). These were times of organized and coordinated efforts between all partners when the severe weather threat was greatest. By far, 3/31 was the best date for data collection as there were several supercells that moved through the domain, including one that produced an EF-2 rated tornado. As Dr. Murphy described, this tornado went through the ”picket fence” of sounding teams. There was also an abundance of inflow environment sampling that day. Of particular interest was the significant increase in low level shear during the afternoon to evening transition period. On other days, the team collected good data in pre-convective environments and weak boundaries ahead of QLCS and supercell activity.

While 3/31 proved to be a fruitful day, there were some challenges overall for the first year of VORTEX-SE as a whole. This past spring season was relatively quiet in terms of severe weather and tornado activity within the domain area, so data collection were at a premium. Also, the convection-allowing models did a poor job of forecasting convective evolution and rarely had a good handle on mesoscale features, and this resulted in poor anticipation of storm initiation, intensity, and interactions. Of course, just the typical southeastern severe weather environment by itself, including complex and extremely fast-evolving events, makes for many challenges. Several experienced investigators familiar with prior VORTEX projects often commented on the difficulty of these issues in comparison with their experiences in the Plains. Dr. Murphy elaborated on some ideas that could help to ensure more data collection in the future. These might include establishing a dense, moveable observation network and perhaps acting on threats just outside of the domain area.

In terms of the science, Dr. Murphy and his students know that tornado formation occurs when a significant amount of angular momentum (vertical vorticity) gets converged to a small radius near the surface, and so they were focused on finding potential impetuses for this process. They were able to observe low LFC environments typically associated with southeastern tornadoes, and they sought sources of near-ground vorticity, unrelated to vorticity-producing mechanisms within a supercell, that might be associated with terrain, land-use, and storm interactions. These boundary layer features and the near-ground vorticity distribution field are what Dr. Murphy hopes to observe more of in year 2.

Some more hopes for next year include research on infrasound sensing of tornadoes, and continued social science research. Core observing platforms are set for 2017 with various agencies and academic institutions contributing mobile sounding and surface observing equipment, and mobile radars. The core platforms are in addition to those instruments awarded via the competitive grant program, and there will be a significantly larger field campaign than year 1. Dr. Murphy explained that ULM was recommended for funding via a collaborative proposal submission with Mississippi State University and UAH.

Following his presentation on VORTEX-SE, Dr. Murphy proceeded to update us on the ULM Atmospheric Science program infrastructure. The radar tower was fully completed last December, and after a long delay, an FCC license was finally granted. However, before turning the radar on, there are some issues that still need to be resolved. The license requires that the radar operate at a higher frequency range to avoid potential interference with other area radars, and this will push the limits of the current magnetron. The magnetron is being tested, and if it works at the required frequency range, then the radar could be activated in time for the fall severe weather season. If not, then activation will be delayed further as a new custom-built magnetron will be required to operate the radar at the higher frequency.

In addition to the radar update, Dr. Murphy let us know about their new microwave profiler radiometer supplied by the LA-BoR Traditional Enhancement Grant for $160,000. It provides continuous temperature and humidity profiles up to 10 km with radiosonde accuracy, and it can generate a skew-t plot every five minutes. For the ULM student operations, there is a plan to add 5 CAVE clients for an AWIPS II environment similar to the NWS operations. And he announced that a new assistant professor, Dr. Kenneth Leppert, has joined the program. His expertise is in WRF model development and research on tropical easterly waves.

Following the minutes review, treasury report, and some discussion of meeting ideas for the month of May, this meeting was adjourned by Eric Carpenter at approximately 2:00 pm.

Minutes were recorded by Eric Carpenter.

June 29, 2016 Meeting

Dr. Todd Murphy speaks during the meeting

For more pictures from this meeting, click here.

%d bloggers like this: