Trevelin ground for long periods of time. Winters are stormy with frequent rain, sleet and snow while summers are cool, windy and relatively dry. Mean annual precipitation is . The precipitation pattern resembles a Mediterranean one, where most (75%) of the precipitation is concentrated from April to August, the cooler months with a dry period from September to March. Snowfall can occur during the colder months while rainfall predominates in warmer months; hail rarely occurs. The mean temperature in Trevelin ranges from in July, the coldest month to in January, the warmest month. Frosts can occur at anytime, even in summer,
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