Ad-Express and Daily Iowegian, Centerville, IA

December 27, 2012

NWS reviews storm's impact

ANDY GOODELL
Oskaloosa Herald

OSKALOOSA — With temperatures staying below freezing for a while, the snow that fell during the blizzard this past week is likely here to stay.

According to the National Weather Service, additional snowfall is possible today and Friday. But conditions aren’t expected to mirror those of last week.

NWS Meteorologist Miles Schumacher said most of the snow this week will take place in northern Iowa; a lack of wind will make conditions unlike those during last week's storm.

Oskaloosa received 4 inches of snow last week, while Des Moines snow total was 12.4 inches. Ottumwa received less than three inches

Schumacher said the snow total differences in last week’s storm were dependent on the storm track. Because some of the precipitation Oskaloosa received came in the form of rain rather than snow Oskaloosa saw less accumulation.

Strong winds on Dec. 20 are what helped blizzard conditions form, said Schumacher. Blizzard conditions occur when sustained or frequent winds of 35 miles per hour for three hours or more take place.

“Technically, it doesn’t have to be snowing at the time,” Schumacher said.

New technology helped forecasters as the storm approached. In September, the NWS in  Des Moines upgraded to Dual-Pol radar. Dual-Pol is expected to show significant improvements in the estimation of precipitation rates, as well as the ability to tell the difference between hail and rain, according to the NWS.

The radar upgrade will also improve the ability to identify areas of heavy rainfall typically linked with flash flood events. It is also expected that there will be improved detection and mitigation of non-weather related radar echoes such as smoke plumes and ground clutter. The “melting layer,” which is helpful in identifying snow levels in higher terrain is also expected to see improvement with Dual-Pol radar.