SUMMARY:
Week #7 of EWP2010 wrapped up the first week of MRMS and GOES-R experimentation. We were all over the CONUS this week, including a perfectly timed event over the Washington DC area for our Headquarters visitors. During this week, NSSL and the GOES-R program hosted the following National Weather Service participants: Rod Donavon (Des Moines, IA), John Murray (New York, NY), James Sieveking (St. Louis, MO), and David Zaff (Buffalo, NY).
REAL-TIME EVENT OVERVIEW:
24 May: “Practice” IOP, first looking at CI products for AMA and DDC, then MRMS products for OUN.
25 May: 6-hour IOP, working High Plains storms, working AMA, PUB, and DDC CWAs.
26 May: Early IOP over Oklahoma (no severe reports), later IOP for the Front Range, DEN and CYS.
27 May: 6-hour IOP over the Northeast U.S., PHI, CTP, and the LMA network near Washington DC.
MRMS:
With Rod Donavon here this week as one of our participants, we were able to get an idea of how his hail diagnosis technique adapted to the MRMS data. The Donavon Technique uses the Thickness between the 50dBZ Echo Top and the height of the melting level (0degC), but diagnosed using traditional D2D methods (all tilts or 4-panels with data sampling) using single radar data and an estimate of the melting level height from either nearby sounding or model data. A suggestion included taking his severe hail probability values based on the technique and gridding them as an additional MRMS product. But his new technique, adapted for the new 1″ hail criteria, also looks at the height of the 65 dBZ Echo over the melting level height, a possible new product we could add to the suite.
A lot of the forecasters liked the Reflectivity at the -20C level, and Jim Sieveking added his unique “red-white-blue” colormap to our system. He and other forecasters create this product locally using the Volume Browser and RUC temperature profiles to sample as you go up in elevation, but that version is single-radar based. The biggest advantage is that the MRMS product is already in a gridded form.
Some of the “sparse grid” MRMS products are good for situational awareness – they show the few storms that “stand out” against the rest, those storms that are obviously severe. These included the 50 dBZ Echo Top and the H50_above_H253.
One forecaster was curious as to what Azimuthal Shear values correlated best with tornadoes. However, as with MDA and TDA, there are distributions of tornadic and non-tornadic storms at all strengths, with a higher probability of tornadoes at higher values. But there was a definite advantage of using the Rotation Tracks to help with polygon orientation and determining intensity trends.
The forecasters felt more comfortable using the MRMS products as the week went along. But they commented that they needed more information about how the 3D reflectivity cube was created, and what went into each product. We re-tooled the training for the following weeks to include more of that information, and eventually will include this in a 20-min Articulate presentation for the Google Earth KML-wrapped PNG image users.
All forecaster mentioned that it would be nice to have more MRMS applications to help with the severe wind decision making. We’ve got enough for hail, lightning, and tornadoes.
GOES-R:
The Convective Initiation (CI) product once again suffered from cirrus obscuration, and very few detections. Some suggestions were to somehow include audible or Guardian alerts for CI detections, and the ability to display contours cloud-top-cooling rates over satellite or radar imagery.
Overshooting Tops and Thermal Couplet detections were rare this week.
We had an opportunity to view real-time pseudo-GLM (PGLM) products over the Washington DC LMA data this week, but the highest flash rates seen (37) were no where near the values seen during the Oklahoma archive case (100+). Some forecasters commented that they still were unsure of what the value meant relative to storm severity that that more experience would be needed to know. They did like to compare the PGLM data with the MRMS data or just the height of the 50 dBZ Echo Tops determined manually. Noted trending up with storm severity, and even a drop right before the tornado in the archive case. Others would like to see a winter convective archive case used. Some also felt that total lightning was a good discriminator of convective initiation.
There are more details on the GOES-R HWT Blog Weekly Summary.
OVERALL COMMENTS:
We had a good discussion on how the AWIPS environment is set up in the HWT. There was a debate over using WES archive cases for all events, in which we could control the diversity of cases looked at, versus real-time events where there is the element of surprise. Noted was the fact that during real-time events, the storm reports are usually delayed, and the reporting time is rarely recorded so it would be difficult to recreate this in an archive situation (unless we guessed at a delay time).
The forecasters were hoping for some default AWIPS procedures to get them started. This was also noted in other weeks, as well as last year, so we’ll have to strongly consider this for 2011.
Greg said he was struggling with the decision to “nudge” the forecasters to look at certain products, or to just let them go on their own to discover them. It was suggested that perhaps next time, to make a checklist of what products should be looked at. [NOTE: Now that the project has ended, I’m realizing that perhaps we needed to include some MRMS “best warning practices” information, for examples: 1) be sure to use the track products to orient the warning polygons at all times, 2) make sure all polygons are “storm-based” – i.e., only one polygon per storm, and 3) separate hail/wind threat from tornadoes with separate polygons.]
Finally, there was a suggestion that we start Monday at a normal shift time of 9am for training, and then leave the option to stay for an overtime shift past 5pm for a real-time event. One issue is that the researchers/developers live local and may not have the flexibility with family schedules to pull a 12-hour shift.
A LOOK AHEAD:
We are taking next week off due to the Memorial Day holiday and a short week. The next operational week is two weeks away, too far into the future for any reasonable prediction.
Greg Stumpf, EWP2010 Operations Coordinator
