Wednesday, December 14, 2011

What Is Dual Pol Radar & Why It's A Good Thing

The National Weather Service announced that dual-polarization radar is making its way to the Philadelphia region soon. The below snippet was captured from a statement that was released yesterday by the Philadelphia NWS office.

Dual polarization radar is essentially a two-wave radar transmission that is sent out and back from the radar site.   The current radars that are used by the National Weather Service send out a single horizontal beam...dual pol radars send out not only that horizontal wave but will also send out a vertical wave as well.

A simulation of that radar transmission is shown'll see the difference between the current radar and the newer radar setup.  It won't change the "look" on your computer screen or smartphone -- the map won't change since that's merely computer programming and the techie work to take what the radar "sees" and spits it out.   What will change, however, is the accuracy of precipitation detection within bands of rain or snow, the intensity of those bands, precipitation type  (rain, snow, or sleet), and improved accuracy in rainfall/snowfall rate.  Given how much rain we've seen around these parts this year it's not a bad thing to have.

In general, the radar's implementation will benefit those in the Midwest and Plains because of its improved accuracy in determining hail size within thunderstorms.   Large hail on the order of baseball size or softball size does not happen often around here but does out in the Plains from time to time.  Dual-pol radar will be able to pick up on hail size more accurately because of the ability to see hail more accurately.

While the radar is out in late January a number of other radars will service the region for the National Weather Service (those are listed up above).