NWS Louisville Doppler Radar All-Tilts Storm-Relative Velocity

Lake-effect Snow and Whiteout Conditions in the Great Lakes Region; Below-average Temperatures in the East

Heavy lake-effect and lake-enhanced snow will persist downwind of the Great Lakes and produce some whiteout conditions that could cause difficult travel conditions. A coastal low will produce moderate to heavy snow over parts of southern and eastern New England into the afternoon. Below average temperatures are expected across the eastern U.S., particularly with chilly morning temperatures. Read More >

NWS Doppler Radar (WSR-88D) Example Products

With NWS Doppler radar, all elevation angles (tilts) within a particular volume scan can be viewed very quickly using the "All Tilts" product. For example, in volume coverage pattern (VCP) 212 (i.e., radar's antenna scan strategy), the radar scans 14 elevation angles in about 4 minutes. From the data, forecasters can quickly assess the full vertical structure of thunderstorms, such as rotation, mesocyclones, mesovortices, straight-line winds, rear inflow jets, shear zones, convergence, and divergence in velocity data. It greatly assists the severe storm warning decision making process.

Above is storm-relative velocity (SRM) All Tilts at 2014 UTC on March 2, 2012. Only every other tilt (elevation angle) is shown (i.e., only 7 images instead of 14). The first (lowest) image at 0.5 degrees elevation shows the mesocyclones of two supercells over southern Washington and northern Clark Counties in southern Indiana. A rear-inflow jet (green inbound values) is also noted in northern Spencer County, IN west of the radar site at Ft. Knox (black circle in northern Hardin County). Rear inflow jets show up better in base (ground-relative) velocity and are associated with straight line winds/wind damage with bowing storms (bow echoes). At higher tilts, the two mesocyclones still show up, indicating deep rotating updrafts. Storm-top divergence is evident at the highest tilt over northern Clark County. This storm produced a strong tornado in Clark County.