St. John's, Newfoundland and Labrador average. This winter precipitation maximum is unusual for humid continental climates, which typically have a late spring or early summer precipitation maximum (for example, most of the Midwestern U.S.). Most heavy precipitation events in St. John's are the product of intense mid-latitude storms from the Northeastern U.S. and New England states, and these are most common and intense from October to March, bringing heavy precipitation (commonly 4 to 8 centimetres of rainfall equivalent in a single storm), and strong winds. In winter, two or more types of precipitation (rain, freezing rain, sleet and snow) can fall from passage of a
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