NWS Doppler Radar Dual Pol

Coastal Storm Impacting the Mid-Atlantic; Heavy Rain and Below Average Temperatures Over the Plains

A coastal storm will bring widespread rain, gusty winds, shallow coastal flooding, rip currents, large surf and possible areal flooding over the Mid-Atlantic region into Wednesday. Heavy rains and thunderstorms, some severe, persist across the Plains. Above average temperatures expected across much of the CONUS, except over the Plains. Read More >

NWS Doppler Radar (WSR-88D) Example Products

Conventional Doppler radar sends out a horizontal energy pulse providing a one dimensional view of precipitation. Dual pol radar sends both horizontal and vertical pulses, providing a two dimensional view. Thus, it provides much better information about the size, shape, and estimated amount of precipitation, distinguishing between rain, snow, and hail. Basic dual pol products include correlation coefficient (CC), differential reflectivity (ZDR), and specific differential phase (KDP). More information is available on our Dual Pol webpage.

Above, two clusters of thunderstorms had high base reflectivity values between 50 and 60 dBZ (upper left). Meanwhile, CC data (upper right) showed high values above 0.96 (dark red/purple) in the same area as the high reflectivity values. High CC indicates similarly-shaped precipitation vs. a mix of types (i.e., hail-rain mix). ZDR (lower right) depicted values of 3.0-5.0 in the same location, suggesting large hamburger bun-shaped rain drops. KDP (lower left), often used to assess heavy rain using dual pol data, showed values of 2.0-5.0 suggesting a large concentration of rain and large drops. The combination of CC, ZDR, and KDP all supported the occurrence of very heavy rainfall with large drops in the storms, and little or no hail. Reflectivity alone cannot be used to specifically identify the exact nature of precipitation type and size in a storm.

Coastal Storm Impacting the Mid-Atlantic; Heavy Rain and Below Average Temperatures Over the Plains

NWS Doppler Radar Dual Pol - Heavy Rain

NWS Doppler Radar (WSR-88D) Example Products