Ground Based Remote Sensing Observations of a Wave and Cold Front Interaction during the PLOWS Field Campaign

This presentation examines a cold front within a weak cyclone over southern Indiana from a multitude of ground based remote sensors on 14-15 February 2010 during the Profiling of Winter Storms (PLOWS) field project (IOP 19). The shallow cold front was observed by the Mobile Alabama X-band (MAX) dual polarization (with surface measurements), the UAH Mobile Integrated Profiling System (MIPS; X-band profiling radar (XPR), 915 MHz wind profiler, ceilometer, microwave profiling radiometer, surface instrumentation, and Parsivel disdrometer), and the NCAR Mobile Integrated Sounding System (MISS; 915 MHz wind profiler and soundings). These instruments were deployed along a line oriented from 250 to 70 degrees, with separation distance of 47 and 15 km, respectively. Additional observations were taken from the Evansville WSR-88D radar (KVWX) and surface stations (AWOS and co-op) in the mobile instrument domain were used to examine the shallow cold front.

The shallow cold front moved over the instrument domain between 0300-0600 UTC and a displayed a structure similar to that of a density current, including a pronounced surface wind shift, a rapid 6-8 K reduction in temperature, a quick rise in pressure of 1.5 hPa, and a shallow depth of less than 1 km. A wave like feature also passed through the domain above the front, which was clearly portrayed as it moved over the MAX radar. This feature was also detected as perturbations in the XPR reflectivity and vertical particle velocity. Prefrontal soundings (from MISS site) show a stable layer with lapse rates of 4-5 K over the depth of the front. The initial cold front was followed by a deeper, but less distinct cold front that passed through the domain 9 hours after the initial front. Both fronts were well sampled by the mobile platforms and the KVWX radar. Wind profiles were available from the MISS and MIPS 915 MHz wind profilers as well as EVAD analyses performed with KVWX and MAX.