Imperial, California short periods of time. The precipitation in the winter months is predominantly rain showers from the occasional winter storms. At times these storms bring cold temperatures to Imperial and surrounding cities, and mountain snowfall to the nearby mountains. Snow is almost totally unknown in the city, except for a powerful winter storm that covered the entire valley with 4 inches snow on December 12, 1934 and a very brief fall of sleet mixed with hail during a shower in December 1967. On average there are about 11 days that dip into the mid to lower 30s. In January, the normal
NEXRAD tornado detection and subsequent warnings. WSR-88D sites across the nation have been upgraded to polarimetric radar, which adds a vertical polarization to the traditional horizontally polarized radar waves, in order to more accurately discern what is reflecting the signal. This so-called dual polarization allows the radar to distinguish between rain, hail, and snow, something the horizontally polarized radars cannot accurately do. Early trials showed that rain, ice pellets, snow, hail, birds, insects, and ground clutter all have different signatures with dual polarization, which could mark a significant improvement in forecasting winter storms and severe thunderstorms. The deployment of the dual