Preliminary Results from the Intermountain Precipitation Experiment

Quantitative prediction of precipitation in operational NWP models is the least accurate over the Intermountain West compared to other U.S. geographic regions. The primary goals of the Intermountain Precipitation Experiment (IPEX) are to (1) understand the causes and variation in orographic precipitation in the Intermountain West, with an emphasis on the narrow, steeply sloped Wasatch Mountains of northern Utah, (2) study lake-effect precipitation downwind of the Great Salt Lake, and (3) improve high-resolution data-assimilation systems, mesoscale model performance, quantitative precipitation forecasts over complex terrain, and quantitative precipitation estimates from the WSR-88D. A secondary goal is to collect electric-field profiles in continental winter storms.

IPEX observing platforms include two NSSL mobile laboratories with GPS atmospheric sounding systems, two Doppler radars on wheels (DOWs), a NOAA P-3 research aircraft, a dual-frequency microwave radiometer, a vertically pointing Doppler radar, and supplemental soundings from National Weather Service upper-air observing sites. These platforms will enhance an existing surface observing known as the Mesowest Cooperative Networks.

IPEX interrogated several storms in northern Utah and southern Idaho during February 2000. Preliminary results from these storms will be presented.