Week #5 of EWP2010 wrapped up with continued CASA experimentation.
CASA:
During the week, CASA hosted the following National Weather Service participant: Steve Nelson (WFO Atlanta, GA).
Steve was joined by CASA participants Ellen Bass, Jerry Brotzge, Kevin Kloesel and Brenda Philips. During the week, several additional CASA staff and students, including Don Rude, Brendan Hogan, and Cedar League, also were in Oklahoma visiting emergency managers in the field during the real-time events.
The week got off to a fast start with a local tornado outbreak, with no time for training or preparing Steve for what to expect, how to use the WDSS-II system, or the communications protocol with emergency managers. Monday (May 10) saw a total of at least 12 tornadoes touch down in the region, but with only one confirmed tornado within the CASA testbed. The one tornado in the CASA domain was on the ground for ~ 10 minutes, but was unique – anticyclonic from a left-moving supercell. The strong magnitude of the low-level velocity shear from CASA prompted Steve to issue a (in-house) warning on the storm, despite the anticyclonic rotation and unusual location relative to the parent supercell. The rotation also was observed by KTLX and TDWR, but at a higher elevation. The tornado was confirmed and classified as an EF-1. Other tornadic supercells initiated within the testbed, but moved east prior to tornado formation.
Steve spent the remainder of the week reviewing both weaker real-time data as well as a series of case study events. A strong cold front passed through the testbed at 4am Wed morning (May 12), which spawned at least one area of rotation as detected by CASA radar KCYR. A small area of damage was reported to the NWS, which coincided with this observed vortex. Several of the archived cases show similar results from supercell events. Data from the May 13, 2009 event revealed several areas of rotation by CASA. The squall line observed April 2, 2010, showed at least one supercell within the line, spawning two strong vortices, each with coincident damage at the ground. The high spatial and temporal data provided by CASA allow the complete development and evolution of these vortices to be better tracked and warned in advance.
Additional tools, such as 3DVAR and real-time NWP (a.k.a., warn-on-forecast), were run operationally during the real-time events. For the May 13 event, Steve first observed rotation within the 3DVAR display. Similarly, the forecast for May 13 allowed Steve much greater insight into what mode of storms to expect. Likewise, during the May 10 event the real-time NWP forecast predicted long-track supercells, with the location and timing very similar to what was observed.
Steve recognized a number of benefits and some challenges with the collaborative and adaptive radar network design. The low-level scanning abilities and high space and time resolution provided significant benefits, particularly in observing and warning on strong low-level winds and tornadoes. The greatest challenge was handling data overload. CASA data were available on both AWIPS and WDSS-II, and Steve used both systems in real-time. The primary need moving forward will be the development of visualization tools capable of easily displaying multiple radars and merged products. The ability to quickly and easily move between products and radars will be critical to using the valuable information available by these new systems.
The CASA experiment has concluded for the spring.
PARISE:
PARISE has concluded its activities in the testbed for the spring. In several weeks, an end-of-experiment quick summary will be prepared by the PARISE principle scientists.
A LOOK AHEAD:
Beginning 17 May, we will begin the second phase of our spring activities with two new experiments, a) an evaluation of experimental Multiple-Radar/Multiple-Sensor (MRMS) severe weather algorithm products, and b) an evaluation of GOES-R convective initiation and lightning mapping products.
Greg Stumpf, EWP2010 Operations Coordinator
Jerry Brotzge, CASA Scientist