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Recent Questions

Question: Saw your forecast for the parades this Saturday. What I did not see on your list of 4 parades and their start times was the Durham Parade, this sat at 10. Why no respect for Durham? — Mark Waller

Answer: The graphics we used to cover parades on the upcoming weekend at that time varied some through the course of the week, and some did indeed include the Durham parade, as well as (variously) the ones held in Cary, Wake Forest, Fayetteville, Chapel Hill and Holly Springs on the same day. We were happy to see Durham bring back that tradition, and in addition to mentions about it in forecasts along the way, our station had representatives in the parade (Ken Smith and Sarah Krueger on a float) and also ran stories afterward including parade video and interviews with participants, spectators and officials.
Dec. 14, 2016 | Tags: controversy, wral.com

Question: How far in advanced of a forecasted winter storm does the national weather service issue watches and warnings? — James

Answer: The Raleigh NWS office shoots for issuing winter storm watches at least 18 hours, and up to 48 hours, prior to the onset of wintry impacts. They also include a confidence criteria, in that they issue the watch when they consider the chance of snow 3 inches or deeper, sleet one-half inch or deeper, and/or glaze ice due to freezing rain of one-quarter inch or more, to be 50% or higher. They may upgrade the watch to a warning when the onset of the stor is 36 hours or less away and they estimate the probability of those thresholds being exceeded is at least 80%. You can find a table of watch and warning criteria used by the Raleigh office at www.weather.gov/rah/criteria. In addition to the watches and warnings, they also issue "Hazardous Weather Outlooks" on a regular basis, and these may mention potential wintry weather up to seven days in advance.
Dec. 13, 2016 | Tags: cool sites, preparedness, winter weather

Question: I was in elementary school in the 1960s. It seems to me that winters were colder back then in the mornings than at present. I remember many mornings walking to school and it being so cold I could see my breath. Was it colder in the 60s in the mornings than it is now? — Ann

Answer: It appears that we did have colder mornings on average during the 1960s than we have recently. We looked at average winter (Dec-Feb) minimum temperatures for the 10 winter periods ending in 1960-1969 and found the average low at RDU was 29.4 degrees F, while at Louisburg (a more rural location) the average then was 24.5 degrees. For the most recent ten winters (ending 2006-2015), the comparable average lows were 32.6 and 28.1, respectively. At each station, the average low in the most recent ten years was about three and a half degrees warmer than in the 1960s. It's worth noting that the 1950s, on average, had winter low temperatures that averaged a little under three degrees warmer than the 1960s.
Dec. 12, 2016 | Tags: cold, past weather

Question: If you were stuck in a lightning storm without shelter would jumping reduce the chance of a hit, as you would spend less time grounded? — Alexander Roa

Answer: It's unlikely that it would make much of a difference, with one possible (and likely small) exception. Lightning can impact people in a number of ways, from a direct strike by the main lightning channel to current conducted by metal objects, side flashes from nearby objects that receive the direct strike, and ground currents emanating outward from the point of the main strike. A direct lightning strike to a person, such as occurs with the main lightning channel passing through the body or a side flash jumping to and through a person, would probably not be prevented or minimized by jumping, as those flashes are intense enough to pass through the space occupied by the person whether you are "grounded" or not (bear in mind that the lightning channel has already overcome thousands of feet of insulating air to reach the surface, so that jumping a few inches or even a couple of feet wouldn't really interfere with completion of that circuit). If a jump was timed to perfection, it could conceivably make a difference to the "ground current" type strike, in which current flowing along the ground enters a person from the ground at a point closer to the strike location and exits back into the ground more distant from the point of the strike. In this case, if your feet happened to be off the surface at the instant the current passed below you, you might avoid being harmed. However, a better idea would be to run as fast as possible to a location with secure shelter from the lightning (an enclosed vehicle or a sturdy building) as opposed to jumping in place - that would also keep your feet off the ground for some portion of the run, and you would be moving toward a greater level of safety at the same time. NOAA has an informative page illustrating the main forms of lightning danger to people, located at www.lightningsafety.noaa.gov/struck.shtml.
Dec. 11, 2016 | Tags: cool sites, lightning, weather & health

Question: When the ice storm of December 2002 hit Raleigh, I was in the 8th grade and didn't really understand the difference between sleet and freezing rain. It became clear when you explained the difference during the evening weather segment of the news on how dangerous this event was (we were watching on a small battery-operated TV because we had no power). Looking back at this event, were you as shocked as the rest of the viewers were about the extent of destruction that an inch or less of ice caused? Do you ever see something like this happening again during our lifetime? — James

Answer: That storm brought together some very cold low level air with a lot of moisture and some relatively warm air not far above the surface, leaving us with a corridor of unusually high glaze ice amounts (ice that was 1/2-1 inch thick in northern and western parts of our viewing area) due to freezing rain. As you noted, this is very different from sleet, which is already frozen into pellets when it reaches the ground. While it is always something of a shock to see the kind of destruction done by this type of weather system, because it is so far outside our routine, day to day experience, it wasn't something that was unexpected once we realized how much ice was likely to accrue by the time this system had moved on, since we knew well that an ice storm follows a well known progression of impacts as ice becomes thicker - by the time we exceed a half-inch, power outages become widespread and tree damage very significant, and this level of impact only grows as the thickness of ice increases further. While the combination of factors that led to such an extended period with high rates of ice accrual are fortunately very rare for our part of the country, there isn't any reason that we can rule out another occurrence at some time in the not so distant future, so it is one of the types of weather disaster that we all need to be prepared for, just in case. If you're interested in details about that particular storm, the Raleigh NWS office put together a very informative "Event Summary" that is available at www4.ncsu.edu/~nwsfo/storage/cases/20021204/.
Dec. 10, 2016 | Tags: past weather, preparedness, winter weather

Question: Who decides what constitutes a 10 or 100-year rainfall event? We seem to be getting a lot of 100-year rainstorms lately, leading me to suspect that our stormwater runoff regulations need to be updated to reflect a new post-global warming reality. — Oak Rapp

Answer: The values of "average recurrence interval" or "return period" for rainfall over a given duration are statistical calculations based on historical data, and are compiled and published by the National Oceanic and Atmospheric Administration's National Weather Service in a series of documents called NOAA Atlas 14. The results can also be accessed and viewed online via a web page called the Precipitation Frequency Data Server (easily found with a web search), where you can drill down to any particular location to find the interval associated with any given rainfall amount and duration, along with a confidence interval of what the true return interval is likely to be based on the available period of record and the uncertainties associated with such analyses. Of course, as conditions change over time, those numbers will be recalculated to reflect new data. It is worth keeping in mind that while the terms like "return interval" imply that a 100-year rain rate should only happen every 100th year, it really means that in a given year, there is a one percent chance of that rate occurring. That doesn't preclude a similar event happening just a few years later. Of course, if they continue to happen at rather frequent intervals, that will eventually cause the calculated recurrence intervals to become smaller. Climatologists have to balance the desire to have such calculations reflect current reality against the possibility of changing the numbers too much based on what may turn out to be a short-term anomaly that isn't representative of longer term trends.
Dec. 9, 2016 | Tags: cool sites, normals, rain

Question: We live near Wake Crossroads in NE Raleigh. Like today, when storms come through Raleigh, it will be raining all around us, but we will not get any rain. Is there something unique about this area that it misses a lot of rain storms? — Jan

Answer: We haven't seen anything to indicate that should be the case, as average monthly and yearly rainfall totals for that general area appear similar to most surrounding locations. Of course, in any given system passing across the region, there can be considerable variability in rainfall amounts due to the typical fluctuations over time and distance associated with many weather features. On the Sunday afternoon that you wrote in, for example, dry air in the lower atmosphere evaporated a lot of the precipitation that fell during much of the daylight hours, especially from around Raleigh northeastward, but as the lower atmosphere became more humid, rain became steadier and heavier heading into the evening and overnight. Observations from a pair of personal weather stations in your immediate vicinity, in agreement with radar rain estimates for that period, indicate you should have ended up with around 3-6 tenths of an inch of rain, similar to much of our area with that disturbance. We've found that the variability of rainfall amounts, and the availability of radar displays to track systems passing through the area (often affecting part but not all of the region) has led people from pretty much every part of our viewing area to have the same perception - that something routinely and uniquely blocks precipitation, storms, etc from their particular location.
Dec. 8, 2016 | Tags: general meteorology, rain

Question: Is it going to snow Friday? — Daniel

Answer: We usually leave short or mid-term questions about the local forecast to the published information on our main weather page, or that you would see in our on-air forecasts, but thought we'd go ahead and note that as we answer this question, it appears there is very little apparent chance of precipitation, and probably little in the way of cloud cover, likely for this Friday. Current projections indicate a strong cold front will pass through on Thursday, followed by the arrival of cold, dry air and a high pressure system to our west as we end the week. if this holds up, we'll see a sunny, breezy Friday with below-normal temperatures.
Dec. 7, 2016 | Tags: snow, wral.com

Question: How come people can survive being struck by lightning? I read somewhere lightning bolts are hotter than the surface of the sun, and I know they can turn sand to glass. Also the Joules contained in one would wreak havoc on the nervous system, so how do people survive? — Alexander Roa

Answer: A big reason people can survive some strikes is that not all strikes are equal. Some strikes involve current that passes mainly over the outside of the body, some pass through the body in a narrow channel that only involves an extremity or two but does not pass through vital organs, some strikes involve ground currents or side flashes that have been dissipated somewhat in energy, and the impact on a person depends heavily on how the person is oriented with respect to the direction that current is flowing, what body parts are in contact wit the ground or other conductor, etc. The result is that strikes involve a wide range of physical impacts to people, from just minor discomfort to fatal injuries. As to the temperature for a lightning channel, the resistant air through which lightning passes can heat to as much as 50,000 degrees F, about 5 times the temperature of the sun's photosphere (the surface you referred to). However, the amount of mass heated to that temperature is very limited, and the duration of a strike is often very short (a small fraction of a second), so that the heating effect of a strike is typically limited, since only a small patch or two of skin would be briefly exposed to the heated air. Of course, burns do occur with some strikes to people, but due to our bodies being reasonably good conductors, the temperatures are generally not extreme over a large area or for an extended time.
Dec. 6, 2016 | Tags: lightning, weather & health

Question: Just for curiosity since we are getting cold at night, do you think we have a good chance of having SNOW, not ice but Snow, this winter? And when in the forecast is the first time Lee County will see SNOW this year? — Heather Thompson

Answer: You may have seen several recent discussions about the reasons predicting snow amounts, or even whether snow will likely be above, near or below normal for the winter season is generally unreliable. For those reasons and more, we really can't give you a meaningful answer about whether Lee County will have some significant snow, or whether your area will likewise escape having any significant freezing rain or sleet, as we head through the winter. Instead, we have to wait and take each potential wintry weather event as it develops, and try to predict, starting a few days in advance, whether it will feature mostly rain, mostly snow or a mix of rain, snow and ice, and how much will occur. Even a few days or a day ahead, those can be very hard to pin down with high confidence!
Dec. 5, 2016 | Tags: snow, winter weather

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