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Recent Questions

Question: What were the dates of the 2014 ice storms in Raleigh? — Margaret Brake

Answer: While there were several brushes with wintry weather during the first three months of 2014, the two events that produced notable glaze icing over parts of the Triangle occurred on February 12-13, with anywhere from about 1 to 3 tenths of an inch of ice reported, and then again on March 6-7, when areas from around Raleigh south and east received very little freezing rain, but parts of Durham and Orange counties got as much as one to three quarters of an inch, causing considerable damage to trees and power lines. You can find links to accumulation maps for these storms at www.erh.noaa.gov/rah/events/.
Sep. 1, 2014 | Tags: cool sites, past weather, winter weather

Question: What is the sunrise and sunset for today? — Kaitlyn Linzel

Answer: We're in a period now where the change in sunrise and sunset from day to day is approaching one of the two maxima of the year (the change is most rapid near the equinoxes). On our web page, you can find the sunsrise and sunset numbers for Raleigh both on our "Almanac" page, and also in the main forecast section. When you mouse over any time period there, you'll see the sunrise time on the "daytime" section for each day, while changing to the "overnight" tab will show the sunset time for that evening. In addition, on our Almanac page you will see a link labeled "U.S. Naval Observatory’s Sun and Moon Data" where you can obtain sunrise/sunset/moonrise/moonset/lunar phase data for any location and any date, should you need it for planning purposes or for reference regarding dates in the past.

Aug. 31, 2014 | Tags: astronomy, cool sites

Question: Does the Farmers Almanac have any science behind it? — David Copperwheat

Answer: It doesn't appear so, as they have not described the methods involved beyond what is written at farmersalmanac.com/farmers-almanac-forecasts/, which boils down to saying there is a secret formula developed in 1818 that only one person knows the details of. Several groups through the years have undertaken efforts to verify the accuracy of the forecasts, which can be difficult due to the lack of detail and the large geographic areas referenced by the outlooks, and generally found the forecasts verify about the same as if they were randomly generated, or based on typical variations around seasonal averages.

Aug. 30, 2014 | Tags: cool sites, folklore

Question: A quick question for your from a long-time fan and NC severe weather 'enthusiast'. Looking back at past tornado outbreaks in NC, I came across March 29, 1991. Unfortunately, I can't seem to find much if any information on the tornadoes that occurred that day. Nonetheless, searching on the tornado history project (THP) website, there are a number of tornadoes across the state, including 2 fairly long track F2s near the western part of WRAL viewing area. Now the really interesting part . . . When I was searching for info on the storms, I found a clip (youtu.be/v6VPW3ir5f0) from the WRAL News from that very evening (3/29/91) that featured your weather report. Although THP data reads that the two F2s hit around 2PM, there was no mention of the activity on your evening forecast/discussion! Were you unaware that the tornadoes had occurred, or am I off on dates/times, or something else? Would love to hear what you think! Thanks! — James Hathorn

Answer: Your date is indeed correct and there were ten tornadoes reported in NC that day, including the two F2 twisters you noted just west of the Triangle. One of those originated near Farmer in southwest Randolph County and ended up damaging or detroying some 68 homes in Asheboro and doing $600,000 damage. Luckily no deaths or injuries were reported. This tornado covered a 28 mile path, while another F2 twister that formed over Chatham County near Siler City and covered about a six mile path that extended a bit into Orange County, damaging 35 homes and destroying four mobile homes along the way, again with no deaths or injuries, but about $250,000 damage. An early evening F1 tornado later that day that moved through parts of Lenoir and Jones counties did result in a reported 33 injuries. A good place to look up some of these details is the National Climatic Data Center's "Storm Events Database" at www.ncdc.noaa.gov/stormevents/. The clips of the newscast you linked to were from the 11PM news, and it seems likely the information about the tornadoes was covered in some detail during parts of the newscast that were not included, and that's probably the the reason they weren't mentioned specifically in the weathercast that came later. Thanks for the "throwback" link!
Aug. 29, 2014 | Tags: cool sites, past weather, tornadoes

Question: Do Arizona's monsoon storms produce tornadoes, and when was the last time a tornado occurred in Yuma? — Chris Filiano

Answer: The monsoon in Arizona is a time of a general south to southeasterly low-level wind flow that occurs during the summer months, bringing relatively moist low to mid-level air into the region and helping to fuel occasional strong or severe thunderstorms, with almost all severe storm reports in the Yuma region tending to occur in the months of July to September. However, the broader environment that these storms form in usually lack the kind of vertical wind shear that supports the development of rotating storms that spawn tornadoes, so they are very rare there. In checking records for tornadic activity in Yuma County, for example, we found just eight reported since 1950 (compared to 35 in Wake County, which is less than 1/6 the area of Yuma). The most recent occurred on August 10, 2006, and was an F0 tornado with a path length of 10 miles and a width of approximately 50 yards, with no damage or injuries reported.
Aug. 28, 2014 | Tags: past weather, tornadoes

Question: You recently showed the view at the airport with the bright sky in the background, but the icon still showed rain and you explained the time delay was responsible. However, in Southern Pines that day, there was a brief, isolated rain shower around 5 p.m. when the sun was getting low. For a time, it was raining and at the same time the sun was shining and casting shadows on the ground as the drops fell. This happens often in the Sandhills area I've noticed. We've always called it a sunshower. Is there a technical term for this? It's also an old wives' tale that the devil is beating his wife. — Ann Hopkins

Answer: There really isn't any special technical word or phrase for this, as it is just a form of rain or a rain shower. However, the "sunshower" term you mentioned is pretty well known as an informal way to refer to such an event, and we've heard of the "Devil beating his wife" reference as well, although we've been unable to turn up where that idea may have originated. While precipitation with some direct sun can occur under a variety of circumstances, it's most common with scattered, fairly small convective cells that quickly grow and dissipate in unstable airmasses, allowing for gaps between the clouds. In addition, if the clouds have fairly high bases and there is some wind shear between the cloud and the ground, it can be raining at the surface with blue sky directly overhead. Finally, these situations can be good for seeing rainbows, provided the sun is low enough in the sky.
Aug. 27, 2014 | Tags: atmospheric optics, clouds, folklore, rain

Question: Can you explain why weather systems in eastern NC are often predicted to differ along the I-95 corridor? It seems to occur in every season. It's often predicted to snow or rain more on one side or the other of this divide. — Steve Cook

Answer: The I-95 corridor happens to lie along a zone in which typical meteorological patterns related to the geography of our region (mountains to our west and the Atlantic to our east, along with a transition from the higher, hillier Piedmont to the lower and flatter coastal plain, all of which run roughly parallel with that highway) and that of the Unites States in general, frequently leads to airmass boundaries, frontal zones and precipitation type, coverage or intensity transitions in that general area. The highway itself has little if anything to do with this, but does serve as a convenient, widely understood marker for quickly describing the location of these focused events or transition zones.
Aug. 26, 2014 | Tags: general meteorology, maps & codes

Question: Last night I happened to be looking out our French doors at just the right time to see a small, localized, white-hot flash of light just outside at the level of our deck. It lasted for a fraction of a second. Immediately afterwards there was a huge lightning flash with the sound of thunder at precisely the same instant - so I knew the strike had been close. What did I see before the lightning strike? — Sandy Parks

Answer: We can't be absolutely sure what you saw without seeing an image or video, but suspect that it may have been something called a "streamer" that is a typically unseen spark emanating from objects on the ground that are potential connection points for the "stepped leaders" that reach toward the surface during a cloud-to-ground lightning strike. When the leader, which originates from the cloud and moves in erratic steps toward the oppositely charged ground, reaches near the surface, streamers can emerge from a variety of surface objects in the vicinity. When the leader reaches within a critical distance of one of those streamers, a connection is completed that allows for a full-bore lightning strike to proceed. You might find some of these terms visualized nicely in a video clip at snowbrains.com/brain-post-lightning-works-w-super-slow-motion-video/. The clip includes super slo-mo segments that illustrate clearly the movement of stepped leaders, and there are a couple of still photos that capture the presence of streamers from the ground or trees as well.
Aug. 25, 2014 | Tags: lightning

Question: I have been watching the progress of rain storms in the mid-Atlantic and Midwest area today (August 19) and yesterday. The heavier storms yesterday were moving mostly East, or slightly South of East. Tonight's storms (as of 9 p.m.) are moving the same direction, including large cells in the Midwest and some moving off the NC coast near Wilimington. However, around Roanoke, VA and around Hickory NC there is a decent cluster of storms that are moving almost directly South at the same time the other storms are heading East. How can this be? Admittedly, the latter storms are relatively small and not moving very fast. — Dave Crotts

Answer: Showers and storms move in a direction and at a speed that is largely related to the average of environmental winds over a significant depth of the precipitating cloud. There are also some complicating effects of "propagation," in which new cloud and precipitation growth along the side or at the rear of the precipitation area, combined with dissipation of existing precipitation areas, can alter the effective direction and speed of motion.

In the case you asked about, the principal issue involved was the existence of a very short wavelength high pressure ridge near the spine of the Appalachian mountains in the lowest 6-8,000 feet above the ground, which produced north to northwest winds over western NC and VA through that layer at the same time that winds at greater altitudes in that area were from the west-northwest, while winds over the midwest as well as over eastern NC were from the west-northwest aloft and west-southwest near the surface. The effect was that shallower, weaker showers in western NC and VA were subject to steering flow that was more from the northwest, combined with an apparent southward propagation component, while the taller and somewhat more intense cluster near Wilmington were in a location where winds over a deep layer averaged out to push them toward the east.
Aug. 24, 2014 | Tags: general meteorology, past weather, thunderstorms

Question: How cool does the temperature need to be for mosquitoes to become dormant? — Rita

Answer: According to local pest control specialist Mitch Taylor and entomologist Dr Waldvogel at NCSU, roughly 60 degrees is a temperature at which the mosquito species common to our area become mainly inactive. An FAQ about mosquito behavior from the Rutgers University Center for Vector Biology additionally notes that most species function best at around 80 degrees, and cease to be able to function at all in temperatures below about 50 degrees.
Aug. 23, 2014 | Tags: weather & health

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