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Question: There's a strong, blustery wind that blows east down Jones St in Raleigh almost every morning. I was walking in one morning with a gentleman who works in the tower at RDU and he said that that wind had a particular name, and he told me what it is but I have forgotten. Do you know? — Scottie

Answer: We aren't aware of a name specific to a westerly wind blowing down Jones Street, but would be interested to hear if someone knows of one. We do wonder if the gentleman may have referred more generically to winds that are strengthened beyond their ambient intensity by being funneled along between a series of buildings in such a way that Bernoulli's Principle and the Venturi Effect come into play, resulting in an acceleration along what's sometimes referred to as a "street canyon" or "urban canyon." Perhaps one of those terms, or something closely related, is what you remember.
Feb. 26, 2015 | Tags: winds

Question: Is there a way to search the weather page for stats on coldest recorded temperature, highest temp, longest drought, etc, as it pertain to RDU? — Dorothy

Answer: Through our Almanac page, you can pull up observed data for RDU that will will include the coldest and warmest records for the date in question, but we do not have a function on the site for searching out more extensive extremes of the kind you're asking about. There are some great sites out there where you can find that kind of information though, either in short summaries of extremes or by way of querying databases. One good example is the State Climate Office site at www.nc-climate.ncsu.edu/climate/nc_extremes.php (there is also a "drought" area on their site. You might also like exploring the Southeast Regional Climate Center site at www.sercc.com (be sure to check the "climate perspectives" section).
Feb. 25, 2015 | Tags: cool sites, drought, records/extremes

Question: Hello! I am a 7th grade science teacher in Siler City. I use your prerecorded online forecasts each year when teaching the unit on weather and climate. While students seem to understand the forecast, they struggle with understanding how forecasts are developed. Do you have recommendations for online resources to aide in this area? — Marsha O'Hare

Answer: There are quite a few web sites that give an overview of how forecasts are prepared, with the understanding that for a particular purpose there may be significant variations. Here are some starting points, and your students may find it interesting to compare and contrast the information they find in these. www.wxonline.info/topics/wxfcstg.html, www.scholastic.com/teachers/article/weather-forecasting, and en.wikipedia.org/wiki/Weather_forecasting. There are quite a few other sites that provide additional, varying descriptions of the forecast process.
Feb. 24, 2015 | Tags: cool sites, general meteorology

Question: Will you ever develop a Weather Alert app for Windows 8.1 phones? I already subscribe to weather call,(2 accounts home/work) which is great but would like to also have the app with it's GPS feature. — Jerry Stewart

Answer: Thanks for being a WeatherCall subscriber, and we're glad to hear you like the service! We realize there's a catch-22 element to this, but our mobile services staff says that whether that ever occurs depends on the market penetration of the Windows 8 phones, which currently is not supported by the weather data and notification vendors who provide the template apps that our customized versions, like WRAL Weather Alert, are built upon. If or when those are extended to include Windows 8 support, we should be able to do the same.
Feb. 23, 2015 | Tags: severe weather, wral.com

Question: Growing up in IN, always heard that it was too cold to snow when it was down in the teens...have noticed that it usually snows the best between 30 to 34 degrees...so, can it get too cold to snow, and is this because at colder temps the air dries out or what is up? Is this true and why? — Anonymous

Answer: In a technical sense, it can't really be too cold to snow, although it is true that the colder the airmass, the less water vapor is contained in a given volume of air, making the quantity of snow likely to be produced lower than might be the case at warmer temperatures. Also, for air colder than about -25 degrees Celsius (-13 F) the snow crystals tend to be tiny needles and columns that do not have the classic "snowflake" appearance.

The "too cold to snow" perception probably arises from the fact that the coldest temperatures many of us routinely experience occur when dry, stable air near the center of a strong high pressure system settles over the region, leaving us with clear skies, light winds and very low morning temperatures. This is a poor setup for any kind of precipitation, of course, and since the approach of a storm system capable of producing notable precipitation over much of our state often drives temperatures up as relatively warm, moist air invades the region, it isn't unreasonable to associate especially cold, dry conditions with a lack of snow.
Feb. 22, 2015 | Tags: cold, folklore, general meteorology, snow

Question: ON THE WINTER SOLSTICE (12/21) THE SUN RISES AT APPROXIMATELY 7:20 AM. WHILE THE DAYS START GETTING LONGER AT THIS TIME (AND THEY DO) THE SUN CONTINUES TO RISE LATER (UP TO 7:24 AM) AND DOES NOT GET BACK TO 7:20 AM UNTIL ABOUT 1/22. I KNOW THE EARTH IS NOT PERFECTLY ROUND - BUT WHAT CAUSES THIS CONDITION? — T Delorge

Answer: You're right that the earth is an "oblate spheroid" rather than a perfect sphere, but that isn't the principal cause of the seemingly odd sunrise and set timing. You were instead noticing an artifact of our planet's tilted rotational axis together with its slightly elliptical orbit around the sun, which leads to some interesting variations through the year between solar time and our clock times. For a couple of weeks leading up to the winter solstice, sunrise and sunset both get later each day, but sunrise times do so at a faster pace so that the total period of sunlight does in fact gradually becomes shorter. After the solstice, there are a couple of weeks with sunrise still trending later, but at a slower pace than sunset so that the overall day length gradually increases. For more detailed background on all of this, try a web search for the terms "equation of time" and "analemma."
Feb. 21, 2015 | Tags: astronomy, general meteorology

Question: When the forecast says wind: N does that mean coming from north or heading towards the north? — Tyler

Answer: In the example you're asking about, a "north" wind means the wind is blowing from the north. Likewise, if someone mentioned that the wind is pushing a balloon toward the east, then they would be describing a westerly wind. In our forecasts and observations, you'll often see something like "Wind SW 10-15 mph," meaning the winds is averaging about 10-15 mph and blowing from the southwest. This convention for describing wind direction is utilized by almost all meteorologists and weather services.
Feb. 20, 2015 | Tags: maps & codes, winds

Question: In recent years, "dew point" has replaced "relative humidity" in weather reports. Having heard the latter for several decades, I find it much more meaningful than a moisture measurement expressed as a temperature. Why the switch? — Anonymous

Answer: At least in some of our weathercasts, we include current observations of both dew point and relative humidity. The reason that we've emphasized dew point more than may have been the case in the past though is that dew point is directly proportional to the amount of water vapor in any parcel of air. Relative humidity is a different way to describe moisture content, but is not a straightforward measurement since it depends on both the amount of water vapor present and the temperature, so that if the relative humidity changes you don't necessarily know if it was because the temperature changed, or the water vapor content changed, or some of both. Which quantity is more relevant depends on what it is being used for, so you could indeed make a reasonable argument about which is more useful at any given time. Near the surface, relative humidity would be more relevant if you're trying to assess the potential for fog to form, for example, but if you're interested in a quick assessment of how muggy the air might feel on a hot day or if you're tracking the movement of moist and dry air, dew point is typically the more relevant variable. At higher altitudes, profiles of dew point are great for monitoring the movement of moist and dry airmasses and very helpful in assessing stability and the related potential for convection and possible severe weather. On the other hand, relative humidity can play a larger role in assessing whether clouds will form in a given layer of air, or how likely precipitation development might be in that layer. We make extensive use of both variables, depending on the problem at hand.
Feb. 19, 2015 | Tags: general meteorology, humidity/dew point

Question: The crescent moon one night around 10:15 seemed so huge and orange colored as it neared the horizon. I checked the www.timeanddate.com website and it was quite close, but was there some atmospheric condition that made it seem extremely large? — Diane Hill

Answer: We didn't find anything that stood out about the night in question. Usually, when there is an unusual redness to the moon or sun that is an indication that there is an elevated level of dust or pollutants in the atmosphere with the right size range to strongly scattered light in the shorter wavelengths like blue and green. As for the size, there aren't many ways the atmosphere can magnify the size of the moon horizontally, and it is much more common for the moon or sun to be "squashed" a bit vertically because of atmospheric refraction variations when seen near the horizon. Nonetheless, the moon and sun often are perceived as appearing much larger when very low in the sky, even though objective measurement using calipers or photographs show that the size is very nearly the same as when high in the sky. This is thought to be due to a visual trick the mind plays on us. For more detail about this phenomenon, you can try a web search for "moon illusion" and "Ponzo illusion."
Feb. 18, 2015 | Tags: astronomy, atmospheric optics

Question: I remember around 1969 or 1970 when I was a kid, we lived in Rocky Mount and that winter it got so cold for so long that the ponds froze over where you could walk on them. In fact, someone drove a VW Beetle on one pond near my house and you could walk across the Tar River in town. Do you have a record of that winter, and how does it compare record-wise to for longest cold snaps? — Anonymous

Answer: A quick check of statistics from Rocky Mount showed the winter of 1969-70 to the be the 9th coldest on average, and that January to be the 6th coldest. Within that January, however, there was a stretch of 4 straight mornings (ending on the 11th) with lows 15 degrees or less, and not long thereafter a stretch of 4 straight days with highs 32 or lower (ending on the 23rd - this is matched by one other stretch that long ending Christmas Day in December 1989). It seems likely that January is the one you're thinking of. The database for Rocky Mount in this case goes back to 1954, so it isn't an extremely long record.
Feb. 17, 2015 | Tags: cold, past weather

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