July 25, 2011 Facebook TwitterMore...


Local weather office has updated radar and will soon have a Facebook page

By IRENE NOLAN



The National Weather Service office in Newport, N.C., has new upgraded radar technology to help meteorologists enhance the forecasts for our area. 

It is based on dual-polarization, or dual-pol, technology, and the eastern North Carolina office is only the second in the nation to get the upgrade. The first was installed in Phoenix, Ariz.

In addition, the meterologists at the Weather Service will be asking to be your friend when the office joins the age of social media with a Facebook page, set to debut on Monday, Aug. 15.

The new radar technology was installed in June and had the local radar shut down for about 10 days. 

Hal Austin, a meteorologist who is the office’s point person on the dual-pol radar, is clearly enthusiastic about his office being chosen as a test site for a technology that will eventually be installed at the more than 120 radars in the National Weather Service network.

According to the NOAA’s Severe Storm Forecast Laboratory website, radars send out short bursts of radio waves called pulses. The pulses bounce off particles in the atmosphere and the energy is reflected back to the radar dish.

A computer processes the returned signals and, through algorithms, can make conclusions about what kinds of particles it "saw," including the directions they are moving (the Doppler effect), and the speed of their movement.


The WSR-88D – also known as Doppler -- radar transmits horizontal pulses, which give a measure of the horizontal dimension of the cloud (cloud water and cloud ice) and precipitation (snow, ice pellets, hail and rain particles).

Polarimetric radars, also called dual-polarization radars, transmit radio wave pulses that have both horizontal and vertical orientations.

“The additional information from vertical pulses will greatly improve many different types of forecasts and warnings for hazardous weather,” according to the website.

“The main benefit is the even better rainfall forecast it can give us,” Austin said.

Therefore, he said, meteorologists can more accurately forecast the amount of rainfall and improve forecasts about flooding and stream and river flow.

It also helps meteorologists distinguish types of precipitation, such as between heavy rain and hail.  In winter, the dual-pol can distinguish whether precipitation is rain, freezing rain, snow, or sleet.  Austin says it can even tell whether the snow is heavy and wet or dry and powdery and will enable better forecasts of the amount of snow.

Dual-pol will help pilots, Austin said, by showing exactly where the freezing level – or bright band – is in the atmosphere.

It’s also useful, he added, in identifying strong updrafts in thunderstorms.

The new technology will improve the detection and mitigation of non-weather echoes on the radar, such as ground clutter.

That last benefit is a major reason that Newport was chosen as the second test site for dual-pol.

Newport’s proximity to the water makes it a good site to find out more about a phenomenon called “sea clutter.”

“Sometimes we experience echo returns over the water and we don’t know for sure what it is,” he explained. “We know from the satellite that there are no storms, but we see the echo.”

Meteorologists in Newport will be exploring the sea-clutter phenomenon and ways to mitigate it.

And the fact that eastern North Carolina is a coastal area that frequently experiences tropical storms and hurricanes, Austin said, was probably also a consideration in awarding the second dual-pol to Newport.

“In a tropical situation,” he said, “it will help us pinpoint where the heavy rain is falling.

Doppler, he added, is “good” at that, but dual-polarization is even better.

According to the Several Storms Forecast Laboratory website, dual-polarization technology has potential to save the U.S. about $690 million annually by improving precipitation estimates.

Although the area is in a severe drought and precipitation has been scarce since the dual-pol began operating, Austin said there have been a few storm events in which it performed really well – especially in pinpointing hail.

Austin is also spreading the word about the Newport Weather Office’s new Facebook page, which is being developed by webmaster Jeremy Schulz.

It will go live at 8 a.m. on Aug. 15.

On it, the weather office will post weather news and hazardous weather stories and ask people to post their severe weather reports and pictures.

The public will be able to ask the meteorologists questions, and folks will be encouraged to post photos from severe weather that will help inform forecasters and the public about such things as waterspouts, ocean overwash on Highway 12, or soundside flooding.

Meteorologists now forecast such things as marine warnings for waterspouts or the probability of ocean overwash, but often don’t know if that weather really happened.

FOR MORE INFORMATION

The National Weather Newport office can be found online at http://www.erh.noaa.gov/mhx/DualPol.php

Check out these links to learn more about dual-pol technology:

Dual-Polarization Training for NWS Partners
(includes training for Non-NWS partners, and Non-Meteorologists too!)

National Severe Storms Laboratory Dual-Pol Page

National Severe Storms Laboratory Dual-Pol FAQ Page



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