Rob has been looking at the Legacy Hail Algorithm on AWIPS to compare with the experimental products. He discovered that the locally run Legacy Algorithm is not synced to updated environmental data. The update time is labeled as several years ago. So that will need to be corrected in the future.
Patrick Burke (EWP Weekly Coordinator, 18-22 May 2009)
Matthew and Mike note that for MESH the associated color tables are slightly different between Google Earth and AWIPS. These need to be the same to avoid confusion about product times, and help the forecasters to “trust” the data on both platforms.
Patrick Burke (EWP Weekly Coordinator, 18-22 May 2009)
Our teams are working in the North Platte CWA. They have sectorized, with Matthew and Mike taking storms west of the longitude of the radar, and Rob and Les taking those to the east. Matthew/Mike have issued one warning, using base data in conjunction with MESH, POSH, and max height of 50 dbZ. Their cell is elongated and straddling the east to west oriented fontal zone. Rob and Les have observed numerous microbursts near the radar. They feel the storms are not severe, but if they had the option – they would issue a Special Weather Statement.
Patrick Burke (EWP Weekly Coordinator, 18-22 May 2009)
Mike and Matthew would very much like to see a MRMS product depicting the max height of the 60 dbZ echo to use in concert with or in place of the 50 dbZ echo product.
Patrick Burke (EWP Weekly Coordinator, 18-22 May 2009)
The cells in far NW Nebraska have weakened. Other multicell storms were located west of North Platte, and satellite showed some vertical development to the congestus located all along the stalled front in north central Nebraska. We have relocalized the workstations, and will begin to simulate warning operations in the North Platte, NE, County Warning Area.
Patrick Burke (EWP Weekly Coordinator, 18-22 May 2009)
Matthew has worked diligently to track down phone numbers of people who live beneath the storm near Harrison, NE, where MESH indicated golf ball size hail earlier. His calls were mainly unsuccessful in reaching people, but one person reported 0.25 inch diameter hail, the same as a recent LSR from the Cheyenne WFO.
Patrick Burke (EWP Weekly Coordinator, 18-22 May 2009)
Both teams have been issuing warnings for hail in far northwest Nebraska. These storms appeared to be in the best environment, taking advantage of moderate mid level flow seen on the Medicine Bow profiler, and somewhat backed northeasterly surface flow just north of the slow moving cold front. Forecasters have been using the Max Estimated Hail Size (MESH) product, which reached near 1.75 inch. They have also been very interested in reflectivity at the 0 and -20 degree C level. They have looked at echo tops products, but mostly for completeness. The echo tops have not influenced warning decisions.
Patrick Burke (EWP Weekly Coordinator, 18-22 May 2009)
Since about 4:15 PM CDT, forecasters have been analyzing data in the Cheyenne CWA, while NSSL scientists provide more in-depth explanation of the various MRMS products. One team has already issued a severe thunderstorm warning for hail. We suspect the event will peak later this evening, however, once the forecasters are fully familiar with the MRMS tools available to them, and when storms move into the North Platte, NE, area.
Patrick Burke (EWP Weekly Coordinator, 18-22 May 2009)
Forecasters have finished with an LMA archive case. Timing couldn’t be better, as the SPC has issued a mesoscale discussion citing a severe weather watch possible in the central High Plains. Forecasters are listening to an end-of-day discussion from the Experimental Forecast Program. This will serve as at least the beginning of a “shift change” type briefing, while we bring the machines up into the Cheyenne, Wyoming, CWA.
Patrick Burke (EWP Weekly Coordinator, 18-22 May 2009)
Forecasters are currently working an archived LMA event, viewing lightning data associated with a number of supercells. Starting at 4 pm CDT, we will initialize the machines to our central High Plains target region for the MRMS IOP. This should give forecasters plenty of time to become familiar with navigating and interpreting the MRMS products as storms develop in Wyoming, before we begin intensive warning operations from 5-9 pm.
Patrick Burke (EWP Weekly Coordinator, 18-22 May 2009)