WRAL.com: Raleigh, Durham, Fayetteville

The most direct way to find your question is to search for the name you used when you submitted it (first name, last name or both). If you did not include a name, then you can search using keywords from your question. Of course, since many weather-related terms are common to a lot of the questions we receive, this may turn up a number of others in addition to your own.

Thanks again for sending your questions to Ask Greg!

Answer: So far, the record for highest low temperature in the Raleigh area is shared among several occurrences of a minimum of 80 degrees. The last time it happened was rather recently, when the Raleigh-Durham airport reported a low of 80 on July 25, 2010, but there area also recorded 80-degree low temperatures in Raleigh on July 17, 1887, June 30, 1936 and July 19, 1942. On a wider basis, there are reports of a tie between Death Valley CA (July 12, 2012) and Khasab, Oman ( June 27, 2012) for the highest low temperature observed, with lows of 107 degrees recorded on those dates.
Apr. 18, 2013 | Tags: heat, past weather, records/extremes

Answer: The diameter of the heated core of a lightning channel has been estimated in a number of ways, with most falling into a range from about .5-8 centimeters (around .2 to as much as 3 inches). While this is pretty small, especially at the lower end, consider that it is or can be much larger than the size of the filament in an incandescent flashlight bulb or the tube in a typical camera flash, along with the fact that you can see city lights, for example, from many miles away. The amount of voltage and current, not to mention the temperature, associated with lightning channels is also much greater than those other light sources, helping to make them readily visible from great distances. The great length of some lightning flashes just adds to this effect.
Apr. 17, 2013 | Tags: lightning

Answer: Ideal winds for an activity like kite-flying would lean toward those that are fairly steady over time, not too strong and not too weak (say a range of about 5-15 mph). One of the factors that would work against this, even in the case of otherwise steady winds, is turbulence. Turbulence can be mechanically driven, for example by wind blowing across a building or line of trees, or thermal, caused by pockets of heated air rapidly rising. In each case (or a combination) turbulent swirls and eddies can cause the air around the kite to suddenly flow up or down, speed up or reverse direction, all making control difficult. The sources of turbulence provide some clues as to the best overall conditions for flying - mechanical turbulence can be minimized by finding an open location with flat ground, while thermal turbulence can be minimized by choosing times when solar heating of the ground is reduced, for example on cloudy days or by flying before mid-morning or late in the afternoon when the sun is at a relatively low angle. Another thought regarding thermal turbulence is that you could sometimes minimize this by flying near shore in a seabreeze or lake breeze that would flow from water toward land from about mid-morning to mid-afternoon on bright, warm days that are otherwise lacking in winds. The air flowing in off the water should be relatively stable and turbulence free compared to that farther over land. If there are buildings or tree lines or other significant obstacles in the area, trying to ensure that you are located on the order of 10 to 20 times the height of the obstacle downwind will minimize the turbulent flow associated with those obstacles.
Apr. 16, 2013 | Tags: winds

Answer: You can check all that for a single site (the RDU airport) right on our web site. Just scroll down to the "data" section of our main page, find the "Historical" column and click the "RDU Rainfall" link. There you'll see accumulated rain versus normal for several different time spans, and above the graphs there is also a selection box you can use to access some other ways of viewing the rain, including a 50-year span of annual totals.

When you're more interested in how rain has varied across the region, you might like to check out the National Weather Service precipitation analysis page at water.weather.gov/precip/. There's lots to explore at that page. To zoom in to central NC, just click the "NWS WFOs" radio button under "location" and select Raleigh. Turning on the county line overlays can also help in orienting yourself. Here you can plot contours of observed rainfall over varying period, or compare the rain to normal by way of anomalies and percentages of normal precipitation.
Apr. 15, 2013 | Tags: cool sites, past weather, rain

Answer: This was a new piece of weather folklore to us, but we did find just a couple of isolated mentions of something along these lines in a quick web search. On the other hand, we also turned up an old English rhyme that stated "If a cat washes her face over her ear, 'Tis a sign the weather will be fine and clear," showing that the same feline behavior seems to have been interpreted to have opposite meanings. We can't think of any reason why either of those would successfully predict rain, or a lack thereof. There are a few of the old weather "wives tales" that have an underlying grain of truth or physical reasoning behind them, but many do not and it can be difficult to understand how they initially came to exist.
Apr. 14, 2013 | Tags: folklore, rain

Answer: We had especially steep temperature lapse rates that day from the ground up to around 1800 feet or so, which meant that relatively mild air at the surface (many readings in the mid-upper 40s) fell off rapidly to below freezing for a couple thousand feet before warming again in an elevated temperature inversion. Snow that was forming around 15-20,000 feet above the ground mid-morning to early afternoon fell into a layer of air that was above freezing starting at about 8,000 feet up and melted into raindrops. These raindrops then fell into the sub-freezing layer from around 4000 feet down to 1800 feet, which caused some of them to freeze into sleet pellets which reached the ground at times. Variability in the elevation and depth of the layers of above and below-freezing air led to swings of precipitation type between sleet and rain, and at times a mix of both. In many cases, when surface temperatures are in the 40s to around 50 the layer of air near the ground is too deep for sleet to make it to the surface without melting again, but we do get an occasional set-up like Thursday that keeps that lowest layer of warmer air unusually shallow. We've seen occasions when temperatures up around 50 still allowed sleet to reach the surface due to strong lapse rates, but those instances are pretty few and far between.
Apr. 13, 2013 | Tags: general meteorology, past weather, winter weather

Answer: That is not only possible, but has happened many times in our area due to the fact that we are often on the borderline for transitions between different precipitation types. In addition to having rain and snow (and sometimes sleet and/or freezing rain as well) in the same day, it is occasionally the case that a mixture of rain and snow can fall at the very same time in the same location. Usually this only occurs for a fairly short time before changing to either all rain or all snow.
Apr. 12, 2013 | Tags: general meteorology, rain, snow, winter weather

Answer: It's easy to understand why you would ask the question, but March 2013 did not end up being a record cold month. However, it didn't miss by all that much, either! In 69 years of records from the Raleigh-Durham airport, this was the 5th coldest on record with an average monthly temperature of 44.9 degrees F (Note that 5 other years were colder, but two of those tied for 4th coldest). This year came in 6.2 degrees below the normal temperature for the month, and a full 15.5 degrees colder than last year (however, 2012 did set the record for warmest March at RDU). The coldest March out there was that of 1960, with an amazingly cold average temperature of 37.6, which was a rather large 4.4 degrees colder than the 2nd chilliest year of 1947. We also checked the records from a site on NCSU property that has a period of observations going back to 1892, and March 2013 was also the 5th coldest in that record, out of 118 years listed (and again, with two of the colder years tied for fourth place).
Apr. 11, 2013 | Tags: cold, past weather, records/extremes

Answer: It's unlikely we'll be able to show both units on maps or graphics as they would become rather busy and cluttered. We do, however, provide an option to display some of the readings on our site in metric units. To toggle this setting on, just go to the "Current Conditions" page and you'll see a link to "Use metric units" under the report from the WRAL studios. This will change the text units displayed on the current conditions page to metric, and this will remain the case each time you visit the site unless you return to the current conditions page and click "Use English units" instead. Note that this change only applies to the current conditions page, and doesn't affect graphic images like the 7-day forecast or temperature maps, which are only rendered and displayed in English units.
Apr. 10, 2013 | Tags: maps & codes, wral.com

Answer: The only weather-related names that we are aware of that are subject to official rules and managed by government agencies charged with weather forecast and warning responsibilities are those for tropical cyclones. Of course, Sandy is an example of such a storm and the name was applied to that storm by the National Hurricane Center, taken from a list of Atlantic Basin names that is compiled and managed by a subcommittee of the World Meteorological Organization. The list includes includes six years worth of names at any time, and those names are re-used every six years unless a storm produces a level of destruction and/or loss of life that would make such re-use insensitive to those who suffered the consequences. In that case, the name is retired from the list and another name starting with the same letter and having the same gender is chosen to take its place. We can be certain that Sandy will be retired from that list and never used again as the name for a tropical cyclone in the Atlantic basin.

The same kind of rules do not necessarily apply to unofficial or informal names that arise by way of social media, journalism, private businesses or popular use.

Apr. 9, 2013 | Tags: Floyd, hurricanes, maps & codes