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.

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Answer: We assume you are referring to the "Get Historical Data" function of our Almanac page, which takes you to a page specific to whatever date is selected. We checked that page for April 27, 2013 and found the high was listed as 72 degrees, the low 53 and the average, as you noted, was 63. This is two degrees below the degree day base of 65, and the page appears to correctly show 2 heating degree days for that date, rather than 4. If we misunderstood where you were seeing the incorrect value, please write back and let us know and we'll try to root out the trouble.
May. 8, 2013 | Tags: past weather

Answer: Once you install the app and establish a primary location, it does not have to be open and running in order to receive alerts. The alerts sounded by the app are triggered by "storm-based" warnings so that the locations covered are defined by polygons specific to the possible impact area of the storm, rather than the older method (still in use for weather radios) of warning by county. This is intended to reduce the number of false alarms when, for instance, a storm is expected to impact a small part of a county.
May. 7, 2013 | Tags: severe weather, wral.com

Answer: While there is a Buckhorn in Orange County that is a crossroads community just south of I-40 a littl west of Hillsborough and Efland, the Buckhorn referred to on the temperature map is a weather station in the vicinity of the northwestern end of Buckhorn Lake/Reservoir, which covers parts of western Wilson and northeastern Johnston County (where the station itself resides).
May. 6, 2013 | Tags: instruments, maps & codes

Answer: There are many web sites and videos that posit a theory that a secret program to alter the climate, depopulate the planet or somehow control people through emission of chemicals is evident in the appearance of long white trails behind high-flying aircraft. However, pretty much every photo and video of the trails, the sky or the lingering cirrus cloud cover on these sites seems to show images of routine contrails (condensation trails), the likes of which have existed since the beginning of high-altitude flight operations. We've delved into this several times in the past few years on AskGreg, and rather than repeating the details here, you can look through those earlier responses by using the "Search for:" box at the top of the list of AskGreg questions. Just enter chemtrails or contrails there and click the find button to turn up those answers.
May. 4, 2013 | Tags: controversy

Answer: Most outlooks for the 2013 Atlantic season indicate a tendency toward above-normal activity. As examples, the forecast from Colorado State University is for 18 named storms, 9 hurricanes and 4 major hurricanes (meaning those reaching category 3 or higher intensity). As a comparison, for the thirty-year period 1981-2010 (used for most climate "normal" calculations) the median observed numbers were 12, 6.5 and 2, respectively. They also indicate the probability of an east coast landfall at 48%, which is above the long term average of 31%.

A local research group at NC State University makes their forecasts in the form of likely ranges, and they are expecting 13-17 named storms, 7-10 hurricanes and 3-6 major hurricanes, generally in good agreement with the group from CSU. The National Oceanographic and Atmospheric Administration's Climate Prediction Center will issue its 2013 projections later in May.
May. 3, 2013 | Tags: hurricanes, preparedness

Answer: Although this isn't really something we have to be concerned about, it does make for an interesting thought experiment, one that has been addressed a number of times. If the sun just disappeared instantly, we would know it a bit over eight minutes later when its light ceased here, and at that same time earth would stop orbiting and begin to travel in a straight line through space. Of course, without incoming solar radiation the earth's surface would begin to cool rapidly, with some estimates indicating the average temperature would fall from the current 57 degrees or so to around freezing after a week, and after a year the average surface temperature would be on the order of minus 100 degrees F. Various forms of life would last for a great variety of different time periods depending on their typical current habitat and adaptations, along with the manner in which they gain life-sustaining energy. Small to medium sized plants, phytoplankton and so on would go pretty quickly due to the loss of photosynthesis, but large trees would continue to live off of stored sugars and water tapped from deep roots, at least until temperatures got cold enough long enough to freeze them to death. People could take advantage for a while of fossil, nuclear and geothermal energy sources to provide light and warmth, and perhaps to sustain some limited plant and animal growth for food, but this would surely become a great struggle in fairly short order for all but a relatively few enclaves. As earth continued to cool more slowly over hundreds and thousands of years, we'd reach a point where atmospheric gasses other than the water vapor we're accustomed to would begin to condense and precipitate out. If some humans were still around then, it would probably be a good bit tougher to keep going. Biologists considering this question do seem to think that one current form of life could continue on just about indefinitely, that being the ecosystem of organisms that live around geothermal vents in the deep oceans. That's in part because those organisms do not currently depend on the sun for sustenance, and also the oceans would develop an ice sheet that would greatly slow additional loss of heat from the deep water below. Areas near ocean floor vents would also continue to receive some of the heat generated by radiation and pressure from deep within the earth. That's a very brief overview of a few of the considerations of how such an even might play out. You can read some others, for example, at www.popsci.com/node/24698 and see a pretty entertaining video discussing some of these issues at www.youtube.com/watch?v=rltpH6ck2Kc.
May. 2, 2013 | Tags: astronomy, controversy, cool sites

Answer: You might like to try out a very nice site hosted by NOAA's National Ocean Service. It is an interactive tropical cyclone track database and mapping system. Regarding your question, for example, I was able to simply type "Tortola, British Virgin Islands" into the location box and click GO, which zooms directly to that location, and displays a default 65 nautical mile radius with every cyclone track from the years 1842-2011. This initially looks like a great number of storms, but you can then apply a filter to search for certain time frames or certain groups of years. In your case, I applied a filter to check for July storms from the entire range of years. The result showed that in during that 169-year span, one tropical storm and four hurricanes passed within that distance of Tortola in July. This equates to about a three percent chance, or a nearby storm in July once every 33 years or so. The site address is csc.noaa.gov/hurricanes/# and there is another place you can go to get month-by-month maps of similar probability contours for the Atlantic basin. It is an answer to a frequently asked question at NOAA's Hurricane Research Division web site, located at www.aoml.noaa.gov/hrd/tcfaq/G12.html.
May. 1, 2013 | Tags: cool sites, hurricanes, past weather

Answer: Stratus clouds are often the lowest that can be clearly distinguished from below as a cloud with a well-defined base that isn't in contact with the ground (in which case it would be considered fog). The base of a very low stratus deck may be a few tens of feet above the ground, but are often on the order of 100-500 feet up. Well-developed cumulus clouds can occasionally be seen with bases at similar altitudes, but usually are somewhat higher, commonly starting at about 2000-4000 feet. On the day you cited as an example, the lowest reported cloud bases at RDU were around 1500 feet above the ground in the morning, with those bases rising to around 4000 feet in the afternoon.
Apr. 30, 2013 | Tags: clouds, past weather

Answer: The great majority of tornadoes fall into the weak intensity/damage categories (EF0 and EF1) and are of very brief duration, usually 1-3 minutes or so, while strong tornadoes in the EF2-3 categories tend to stay on the ground more on the order of 6-10 minutes, while violent tornadoes in the EF4-5 categories often last 20-30 minutes. All of these numbers are subject to great variation however, with a few examples of each intensity sometimes lasting much longer or just a fraction of those typical durations.

Those numbers refer to the length of time the tornado exists. The duration of a tornado's impact on a given location, of course, depends on the size of the tornado and its forward speed, both of which which can also vary greatly, but most tornadoes would produce damaging winds at a given point for anything from just a few seconds to as much as a minute or two.
Apr. 29, 2013 | Tags: severe weather, tornadoes

Answer: We had the 5th coldest average temperature for March 2013 out of 69 years of records from the RDU airport. There were actually five other years with colder March temperature, though, since 1965 and 1958 tied for 4th place on that list with average temperatures of 44.6 degrees, 5.8 degrees below the 69-year average value for March. The sample of summers following those 5 Marches is small enough that we can't draw many conclusions in a statistical sense, but all of them did end up among the coolest 25 summers in the 69 year period. None of them was as cool relatively speaking as the March they followed, the closest being summer of 1965. March that year was 4th coldest, while the summer was 9th coolest on record. On the other hand, the coldest March, 1960, was followed by a summer that was 23rd coolest. Another mildly notable point is that the 5 summers involved ran anywhere from .6 to 1.9 degrees below the 69-year average value. However, when you check them against a more typical 30-year climatological average based on the first 30 years of the record from RDU (1944-1973), which encompasses all 5 of those years, the differences from that average range from +.2 to -1.1 degrees, placing them more toward the middle of the pack, as opposed to the cool end of the spectrum, in the context of that time period.
Apr. 28, 2013 | Tags: past weather, records/extremes