NWS forecasters will be evaluating a new weather-adaptive three-dimensional variational data assimilation (3DVAR) system from NSSL/CIMMS that automatically detects and analyzes supercell thunderstorms during the 2011 Experimental Warning Program in the Hazardous Weather Testbed. The program runs from May 9-June 10, 2011.
Early identification of supercell thunderstorms is critical to the public severe weather warning process since 90% of supercell thunderstorms produce tornadoes, large hail and damaging winds.
The 3DVAR system uses data from the national WSR-88D radar network and NCEP’s North American Mesoscale model product to automatically locate regions of thunderstorm activity. It is able to identify deep rotating updrafts that indicate a supercell thunderstorm at 1 km resolution every five minutes in these regions.
The 3DVAR analyses contain full three-dimensional wind field and precipitation fields, and can provide estimates of storm dynamics such as the strength of the updraft. In addition, by combining observations from multiple radars, the 3DVAR system provides a single information source that can reduce the observational data flow that challenges forecasters every day.
During the 5-week project, 3DVAR products will be available to participating NWS forecasters in near real-time to determine if these high-resolution analyses can improve their awareness of the hazardous weather threat.
The system performed well during the spring of 2010, detecting and analyzing significant severe weather events including tornado outbreaks in Mississippi, Arkansas, Kansas and Oklahoma. More recently, the significant tornadoes in Greensburg, Pa. and Mapleton, IA in early April were also well identified and analyzed.
Initial development and testing of the 3DVAR was done at the Center for Analysis and Prediction of Storms at the University of Oklahoma. Preliminary display of the product can be found at: