Daily summary of operations–includes information on which projects ran operations and problems that may have occurred.
FAIL. A rolling snowball of computer problems led to no MR/MS IOP during the evening hours. However, the day was not a complete loss as the forecasters looked at one more CASA and PAR case, received their introduction to the LMA and went through an introductory LMA playback case. The forecasters were able to view the MR/MS products in wg and Google Earth, however, the AWIPS problems proved to be a major distraction.
Kiel Ortega (EWP Weekly Coordinator, 4-8 May 2009)
Our forecasters have done their training today. They have viewed all into presentations except for the LMA presentation. They received a fair amount of WDSS-II training and are now beginning their initial PAR and CASA exercises. The next few days look to be more intensive with many opportunities for LMA and multi-radar IOPs forecasted.
Kiel Ortega (EWP Weekly Coordinator, 4-8 May 2009)
The forecasters began the afternoon by evaluating the 5/7/08 tornado archived CASA event. Comments included: the rapid update andd closely spaced radars caused the forecasters to stay more focused on the evolution; it was sometime difficult to choose the best of the single radars to concentrate on; the wind analysis should be available in the WDSSII GUI, it was quite challenging to manage the wealth of information.
After this, the forecasters evaluated the 10 July 2006 wet microburst archived PAR event. The forecasters commented that their situation awareness helped thme to be better prepared for the nature of the event. They loooked a lot at the LLSD Divergence prodcut to analyze the Mid-Altitude Radial Convergence (MARC) signatures.
The IOP was centered on Oklahoma and was planned to involve mainly the PAR data, and perhaps the CASA data if storms formed in that smaller domain (the LMA network was unavailable today). We began the IOP at 530pm, but the cap held and held and held, until storms broke through around 7:30pm in western Oklahoma. The forecasters evaluated real-time PAR data, in conjunction with the WDSSI MRMS data, on an isolated supercell storm, mainly a large hail producer, as it moved southward through Dewey and Custer Counties. Using AWIPS, the forecasters issued severe thunderstorm and several tornado warnings on the storm. They noted that the MRMS rotation tracks indicated weaker shear than indicated on the PAR. This was primarily because the PAR was looking above the 0-2 km AGL layer used to compute the MRMS azimuthal shear products. The MESH swaths helped with the polygon cone orientation once again.
Figure 1. MESH Tracks.
Figure 2. Rotation Tracks.
Greg Stumpf (EWP Weekly Coordinator, 27 Apr – 1 May 2009)
The forecasters began the day by evaluating the 10 Feb 2009 case using the Lightning Mapping Array (LMA). Some comments included: coupling the data with the more-familiar NLDN (cloud-to-ground data) help with the analysis; rapid-update of data helped with updraft identification versus just 88D data; the units were difficult to understand (flashes/km^2/s); Observed the “dipole effect” on some of the storms; saw potential value for convective winter precipitation, aviation interests, and transitions from severe to heavy rain.
For the evening IOP, we worked a pretty active event in the southeast Texas Panhandle just east of Lubbock today evaluating the multi-radar/sensor algorithms and issuing experimental warnings using AWIPS. There were a number of supercell storms, one which produced several significant tornadoes. Large hail and damaging winds were also reported, including a nice example of a left-moving storm which created a hail swath who’s movement was contrary to the rest of the day’s storms.
Figure 1. MESH tracks, with left and right moving storms annotated.
Once again, the multi-radar MESH and MESH swaths were very useful for diagnosing the severity and for the orientation of the warning polygon cones, which appeared more “storm-based” than the official NWS warning polygons. The forecasters felt more comfortable with the MRMS products today since they already had a day of experience with them, and felt their lead times were improved. Noted that the MESH estimates on the left-mover were about 50% of the reported hail size – this same observation has also been made by the NSSL researchers. The other hail diagnostic parameters appeared to indicate smaller hail than was observed with the left-mover. There was a recommendation to be able to overlay the MRMS data as contours over the base single-radar data.
FIgure 2a. EWP-generated warning polygons.
FIgure 2b. NWS-generated warning polygons.
The rotation tracks products were also useful for the diagnosis of the tornado potential, and they also aided in the placement of the polygon cones, however a lack of “threshold guidance” was mentioned. Something like the WDTB Tornado Warning Guidance statistics for the LLSD algorithms should be considered. It was again commented that anticyclonic rotation tracks for the left-moving storms would be useful. In addition, “mouse-over” trends, as well as time-height trends of the MR azimuthal shear products could be useful.
Greg Stumpf (EWP Weekly Coordinator, 27 Apr – 1 May 2009)
The forecasters started off the afternoon running through two archive CASA cases. These were the 10 Feb 2009 Central OK tornado case, and the 8 May 2007 mini-supercell tornado case. A quick summary of the comments relayed during our post-mortem briefing include:
The evening multi-radar/sensor algorithm IOP was for two isolated supercells in SE NM. The first storm occured just N of Roswell, but was unfortunately trending to weaker intensity just as we started working it. We localized to WFO ABQ and used the Cannon AFB 88D (KFDX) radar to support warnings. The forecaters issued several SVR warnings on the cell, but the warning server hiccuped, and these warnings were not saved.
Nevertheless, a second more-severe supercell deveoped just E of Carlsbad, and the forecasters warned on that storm for about 90 minutes, both SVRs and TORs. We localized to WFO MAF and used the Midland 88D radar (KMAF) to support the warnings. To support the severe hail decisions, the forecasters used the H50_Above_H253 (50 dBZ above -20C altitude), 50 dBZ Echo Tops, and the MESH products. The MESH swaths were particularly useful in placing the proper warning polygon angle to capture the storm motion. The figures below show the differences between the EWP experimental warning polygons (Fig. 1) with the offical warnings from WFO MAF (Fig. 2). Note how the EWP warnings capture the storm motion better.
FIgure 1. EWP Warnings (amber = SVR; red = TOR)
Figure 2. WFO MAF warnings (amber = SVR; red = TOR)
There was generally good agreement between the MESH estimates and the very few hail reports from these storms. The forecasdters commented that it would be nice to be able to have a user-configurable Echo Top product so that one could choose the dBZ level on the fly (e.g., 60 dBZ Echo Tops).
The forecasters also issued a TOR on the storm, albeit after the WFO MAF pulled the trigger. The reasoning for holding off on the TOR was a temporary decrease in the LLSD multi-radar azimuthal shear trends. When they re-strnegthened, they issued a TOR.
The forecasters recommended the ability to overlay contours of the multi-radar fields over the single radar images. They also recommended that the EWP have several AWIPS default procedures with the WDSSII grids in place before the new set of forecasters arrive.
Other assorted comments: The MRMS products saved time by calculating heights and reflectivities within hail growth regions, versus traditional analysis methods. The 18 dBZ Echo Top color scale needed to be improved. The 1-3 minute latency on the MRMS grids sometimes impeded the full comparison to 88D data. Anticyclonic rotation tracks would be useful.
Greg Stumpf (EWP Weekly Coordinator, 27 Apr – 1 May 2009)
Today we crammed! Got the general orientation, WDSSII GUI, PAR, and CASA training in as quickly as possible in order to work an early IOP on the storms in Central OK. Unfortunately, as soon as we were ready, the storms decided to fizzle out. Therefore, we conducted a very short real-time IOP on the remaining convection using the PAR data. There was one decent example of the descending reflectivity core that was highly resolved by the PAR data, but for the most part, there was little to be observed.
The rest of the evening was spent having the visiting forecasters go through a PAR archive case (T.S. Erin Aug 2007) to gather feedback. We then completed the training sessions for the multi-radar/sensor applications and the LMA project during the final hour of the shift.
DY2 appears to be a West Texas event, and most likely our IOP will focus on the multi-radar/sensor applications.
Greg Stumpf (EWP Weekly Coordinator, 27 April – 1 May 2009)
End of IOP. Sent forecasters home. CASA now sampling data but we will look at this first thing tomorrow. Most feedback today will be on long range PAR which is not the best especially since this was (so far) mainly a wind event.
Liz Quoetone (EWP Weekly Coordinator, 2-6 June)
The IOP today lasted from 5:15 pm to 7:30 pm, and we shut down early to save our energy for Thursday’s potentially significant event. For the first time, we concentrated on all 3 threats (severe hail, severe wind, and tornado) for multiple storms near the Northeast Colorado/Southwest Nebraska border region. We had two teams, Chris/Milovan and George/Jon. One team member monitored the near-storm environment and interrogated the base radar data using AWIPS, while the other team member created the probabilistic hazard forecast grids. The team members switched roles around 6:20 pm.
Chris reported it was hard to “ramp up” from a cold start. He added it would be hard to predict how the work load might be distributed around the WFO in a warning event if probabilistic grids were the primary product. George assumed the software would be easier to use and more stable in an operational environment, and he thought there would still be the same difficulties anticipating short-term changes in storm motion and intensity. In terms of workspace management (desktop real estate), Jon said it was a good idea to keep the product generation screen separate from the data interrogation screen. Everyone reported it was not easy to keep the creation polygons visually separate when working all 3 hazards at once on the same storm, and therefore hard to work with them.
Kevin Scharfenberg (EWP Backup Weekly Coordinator, 2-6 June)
Group looks at summary of threat areas during the evening. Greg talks about a way of doing this in the future might be to hand off storm “objects” to next CWA for a more seamless way of doing things. George brings up that the forecaster in the next CWA may very well decide probs are too high and summarily drop them showing a pretty dramatic change across the CWA border. No one issued TORs and discussion was that environment in the area of the storms was not as favorable. Also looks at the storms earlier from DDC was not sampled as well. All had high threat values for hail and wind. Hail reports were upwards of 4 inches with several mesonet sites showing 70+mph winds.
Discussion also brought up the Call to Action statement about tors when in a Tor Watch (NWS Directive). Consider a PW version of this that puts on a low prob tor threat.
Interesting observation that storms tonight moved across a “dry tongue” and seemed to transistion to more of a wind threat. Storms then went back into the moist air and produced more large hail.
LizQ
Followup:
There were some technological challenges to overcome on Tuesday. It appears there might have been a network hiccup or other sort of glitch near the start time of the IOP (6 pm CDT) that caused a chain reaction of other difficulties. First we noticed the NTI switch which controls the situation awareness display was on but the web interface was unresponsive. This required a hard reboot of the switch. Then we noticed we could not add a source in WDSS-II because the source list was empty. The “real time” radar list in Tensor was blank as well. When we would manually type in a radar URL, sometimes we did not get any products back. It seemed the MESH was significantly underestimating the hail threat with some storms as well, so it is possible that algorithm was not “seeing” all the radars either. This required intervention to reset all the radars, which when solved also seemed to help MESH performance. Finally, the fact some products were not updating caused a glitch with the warning generation software, since the current threat areas were attempting to sync to old product valid times.
Kevin Scharfenberg (EWP Backup Weekly Coordinator, 2-6 June)
All three forecasters spent time doing Prob Warn on storms moving out of the Northern Rockies. Primarily used Rapid City radar. In general, group felt comfortable with software and outlined threat areas for hail, some wind, and a tornado at the end. Tomorrow looks like a similar IOP in the evening somewhere with Archive cases during the afternoon.
Liz Quoetone (EWP Weekly Coordinator, 2-6 June)