At the start of the 1 PM meeting on 6/4/2009, the group summarized yesterdays activities.  We did an LMA IOP for LWX/AKQ, then PAR and CASA archived events.

LMA IOP

• We re-examined the 3 storms around 1950 that had varying LMA attributes vs. CG attributes.  In particular one storm that looked impressive on radar had very high amounts of CGs, but LMA didn’t show much.
• Need to be able to explain why the storm didn’t show up in LMA yet had high CG rates and good reflectivity characteristics aloft, because this particular storm would be an example of when the LMA doesn’t not perform as expected, and in a way detrimental to storm interrogation.
• MESH didn’t agree with the VIL, LSRs, Z at -20C…seemed to overestimate the hail in the LWX CWA
• LMA helped get a warning out quicker than normally would b/c they were able to monitor trends in the LMA, looking for a rapid increase in flash rates
• For warning decisions, Bill/Veronica used VIL, Z at -20 C, MESH, and was looking for things to agree with each other and with the LSRs they were getting
• For warning decisions, Pete/Jenni focused more on LMA rather than warning decision making.
• Low values in LMA b/c of temporal smoothing ocurred which made things hard to interpret
• LMA didn’t respond the same way that CG rates do as the storm intensifies and grows in vertical depth.

PAR

• Pete very excited about using PAR for tropical supercells
• TS Erin case had very clear signatures, liked the time resolution of the data and watching the evolution of the convergence in low levels in the hook echo region.  Issued a warning when convergence increased, knowing that an increase in rotation was likely to follow.  Admittedly the convergence signatures in tropical environments have a high FAR.
• See the same things with the 88D given similar resolutions, you just see them a few minutes sooner
• Yes, warnings could come out a few minutes earlier…but also can see a situation arise when they wait for another scan…60 sec…then wait another…then another since it’s only 60 sec.  Would be interesting to do a study with experienced forecasters using PAR data to see how they react to the vast amounts of data rapidly updating in a warning environment.

CASA

• showed reflectivity do-nut which the 88D did not…also was able to see the rotation intensification better than with the 88D. (May 2007 event)
• CASA had far better location of the tornado relative to the 88D.  1500 feet (CASA) vs 2200 feet (88D)
• Good: see things faster and better low level coverage, could see things you wouldn’t normally see with the 88D, especially with the varying viewing angles
• Lots of things we don’t understand in the CASA data since haven’t seen before. Big learning curve. Change in methodology will be warrented.

Liz Quoetone and Paul Schlatter (EWP Weekly Coordinators, 1-5 June 2009)