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Recent Questions

Question: Since there was a total lunar eclipse last week, when will the next one be for North America? — Tony

Answer: The total lunar eclipse that occurred on April 15, 2014 was blocked from view by cloudiness across most of our viewing area. The next total eclipse visible from here will occur on Wednesday, Oct 8, 2014, with totality beginning at 6:25 AM EDT and ending at 7:24 AM. For the Raleigh area, this means that the moon will still be totally within Earth's shadow as it sets at 7:20 AM.
Apr. 24, 2014 | Tags: astronomy

Question: What is going on with the RWI weather station? Will it be back up or has it died due to a lack of funding? — Mark Clayton, Nashville

Answer: As you've probably seen by now, the weather instrumentation at the Rocky Mount-Wilson airport has been restored to a fully operational status. The main sensor suite there went out of service beginning on April 2nd and was restored on April 18th, with only barometric pressure and the presence of thunderstorms reported from the site during the interim.
Apr. 23, 2014 | Tags: instruments

Question: How do I look up the actual high and low temperature for a range of days for a specific location? — Ken Sikes

Answer: You can click the "almanac" link on our main weather page, and there you'll find a "Get Historical Data" section where you can enter a date of interest and click the "send" button. That will default to a page with observations from the RDU airport for that date, but once you are there you can either search for another location using the search box near the top of the page, or change the weather history location using a box along the right hand side of the page. In addition, you can change the display from "daily" to "weekly" or "monthly" and scroll down to see a listing of daily high and low temperature, precipitation, winds, observed weather phenomena, and more.
Apr. 22, 2014 | Tags: past weather, wral.com

Question: I am told that there was a strange weather phenomenon in Falcon, NC on July 17, 2009 that produced fireballs from the sky between 7pm and 9pm. Do you have a record of any such an event? — Karen

Answer: We were unable to turn up any news accounts that addressed such a phenomenon around the Falcon area, which is on the Cumberland-Sampson County line. There were thunderstorms in that are during the evening, including the time frame you're asking about, so it seems possible the reports could have been associated with nearby lightning strikes. Sorry we do not have any further details that might help.
Apr. 21, 2014 | Tags: past weather, thunderstorms

Question: If a tornado was coming toward the DualDoppler5000, would it be damaged or not? — Hope Beltran

Answer: It would depend on how intense the tornado was, and how close it passed to the tower and radome. Radar towers and dome covers are engineered to withstand rather high winds, but as with any other man-made structure, there are limits and a direct strike by strong or violent tornado could very well inflict significant damage on the system.

These kinds of impacts have occurred before. In 1973 a tornado in Brent/Centreville AL took the roof off the National Weather Service office there and destroyed the radar as it passed through, leaving only the tower standing. There is a very interesting series of photos and captions about the event at brenttornado.wordpress.com/brent-tornado-on-centreville-radar/. In May 2008 a thunderstorm downburst (straight-line winds) that were estimated at around 90-100 mph damaged the radome at Laughlin AFB, TX, as shown in the picture at www.srh.noaa.gov/topics/attach/images/dome1.jpg. In another example, a pair of very intense wind gusts did severe damage to the Reno, NV weather service radar in December 2008. You can see a short presentation about that event at www.wrh.noaa.gov/rev/current/KRGXDomeFailure.pdf.
Apr. 20, 2014 | Tags: cool sites, severe weather, tornadoes, weather radar, winds

Question: I hear you talk a lot about switching between the Dual Doppler 5000 and NEXRAD during Severe Weather. Are the Dual Doppler 5000 and NEXRAD two separate radars or are they just different modes of the same radar? — Justin

Answer: They are two different radars that are located a few miles apart from each other near the Wake-Johnston county line. Dual Doppler 5000 is a dual-polarized radar that our station owns and operates, while the NEXRAD is owned and operated by the National Weather Service. Having access to data from both radars provides a wealth of complementary data, since they operate at two significantly different wavelengths and with different processing software that provides a range of products we can use to detect and analyze precipitation areas and other phenomena. As one example, the NEXRAD radar operates in a "volume scan" mode that provides data at multiple levels, which is very useful bu also causes a 5-6 minute delay between position and intensity updates, which can be a meaningful time/position lag for fast-moving or rapidly changing echoes. Conversely, we run Dual Doppler 5000 in a continuous scan of a single elevation angle most of the time, which samples the same location about every 40-60 seconds. Having both radars available also provides a beneficial redundancy when one of the systems is out of service for maintenance.
Apr. 19, 2014 | Tags: instruments, severe weather, weather radar

Question: Why aren't the current temperatures being listed for Wilson on the weather forecast and the web site any more? — Sonny Thomas

Answer: Those temperatures are automatically fed in from a weather station located at the Rocky Mount-Wilson airport, and that station was placed out of service for maintenance by the FAA. When the site is functional again, its current conditions reports will return to our on-air maps and web site.
Apr. 18, 2014 | Tags: instruments, maps & codes

Question: How do you compute the "normal" high and low for each day? — J.T. Scheick

Answer: Those values are computed by the National Climatic Data Center once every ten years, and are based on observations covering a 30-year period ending with the most recent "zero" year. At the heart of the process for normal highs and lows for each day is a simple average of the 30 recorded highs or lows on that date covering the period of interest (for current normals, this means 1981-2010). However, in order to ensure that daily normal values and monthly normal values are consistent with each other (giving priority to the monthly values over somewhat more noisy daily figures), the daily averages are then reprocessed using a constrained harmonic least squares fit. If you're interested in details regarding this process, see the short paper at www1.ncdc.noaa.gov/pub/data/normals/1981-2010/documentation/temperature-methodology.pdf.
Apr. 17, 2014 | Tags: cool sites, normals

Question: Was there an El Nino last winter? — Abdulrahman

Answer: We aren't sure if by "last" you're referring to winter 2013-14 or the previous winter, but in either case the state of the El Nino/Southern Oscillation cycle during both of those winters was neutral, meaning neither an El Nino nor La Nina pattern was in place. Before that, winter 2011-12 was a La Nina season, and the most recent El Nino winter was that of 2009-10.
Apr. 16, 2014 | Tags: el nino/la nina, past weather

Question: Between 4:30 and 5:00 on the morning of April 2, 2014, I saw what I presumed to be a planet, very very bright and beautiful in the southeast sky. Can you tell me what it is? — Amy Pierce

Answer: Your description is a good one for the recent appearance of Venus as the "morning star," meaning it has been in a position relative the the earth and sun to shine brightly in the morning sky, rising just ahead of the sun and then becoming invisible as the sky brightens up. In other points along its orbit, it is positioned to set not long after the sun, becoming brilliantly visible as the sky darkens. It switches between being the "morning star" and the "evening star" about every 9.5 months, with the next change to evening coming as we head into November of this year. Venus is the third brightest celestial object, behind only the sun and moon, so it really stands out as an especially bright, steady light in the morning or evening sky.
Apr. 15, 2014 | Tags: astronomy

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