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Question: I am doing a science project on how climate affects the growth of a tree. I have a cross cut of a tree and have counted the rings to determine it is 90 years old. I wanted to know if you knew where I can find the records for the last 90 years for the recorded annual precipitation in Holly Springs? — Brooke

Answer: It's unlikely you can dig up precipitation totals specific to Holly Springs, but you can find data that far back for the "Raleigh area" using the climate data web page at xmacis.rcc-acis.org. Just mouse over "single station" and select the "Seasonal Time Series" option. Then click on Options and select the variable precipitation. Finally under "Station selection," choose "Raleigh area" and click "Go" to see the data.

Feb. 28, 2017 | Tags: cool sites, past weather, rain

Question: When was the last time we set a record low in the Raleigh area? It seems like recently we've set a lot of record highs but no record lows here. — Bill

Answer: The most recent record low we could find at RDU was set on October 19, 2015 when the temperature dipped to 32 degrees. Since that time, we've tied or set new record highs on ten dates, most recently February 12 of this year, when we reached 83 degrees.
Feb. 27, 2017 | Tags: records/extremes

Question: With a winter this warm this summer is going to be an absolute, unbearable scorcher, isn't it? — Jonathan

Answer: The historical correlation between winter temperatures and the following summer is low enough that it simply doesn't allow us to infer a hotter than normal summer based on a warmer than normal winter. That said, based on current extended climate model projections, the Climate Prediction Center does have our area in a summer outlook that shows the odds tilted by a small amount in favor of warmer than normal levels for the season. The probabilities involved are in the upper 30 percent range for having an above normal summer, the lower 30 percent range for having near-normal summer temperatures, and the upper 20 percent range for having a below-normal summer overall.
Feb. 26, 2017 | Tags: heat

Question: Just a few days ago the mobile app showed nightly temps as being in the low 20s; WRAL online showed above freezing, and online was indeed correct. Even today there are couple-of-degree differences in them, but if they are all from WRAL why would there be a difference in the two at all? — Amanda

Answer: One of the issues involved here is that the mobile apps with hourly temperatures are location-aware, and have to account for the possibility that people will check the app for a location that is far outside of the immediate Triangle area, and sometimes even out of state. For that reason, the hourly numbers are pulled from a gridded digital database driven partly by computer models and with adjustments by human forecasters with the NWS. This allows the apps to work regardless of your location in the United States. However, in the immediate area of the Triangle, this can lead to occasional differences between the numbers from our 7-day online forecast highs and lows, which are input directly by WeatherCenter meteorologists, and the highest or lowest hourly numbers that appear on the apps. This can make it worthwhile to always check the written 7-day forecast in addition to the hourly forecasts, since we provide some added descriptive context when needed. These forecasts can be accessed directly in the weather apps, as well as at wral.com/weather on any browser.
Feb. 25, 2017 | Tags: maps & codes, wral.com

Question: There is a large beech tree in the woods near a horse trail with a line drawn about a foot off the ground and the words SNOW and a date of April 16, 1938 or 1939. Would you please check your records for any large snows on or around those dates? — Jo Riggan

Answer: As you'd imagine, April is very latein the year for snow in central or eastern NC, and it is a very rare, though not unknown, occurrence. In Raleigh, for example, April 3rd of 1915 brought a 10-inch snowfall, while almost 2 inches fell on April 18th in 1983. However, while we didn't know the particular location you're asking about, in checking multiple observation sites around much of our viewing area, we couldn't turn up any reports of measurable snow in April of 1938 or 1939 (there was a report that a trace, or less than one-tenth of an inch, of snow was recorded in Roxboro in April of 1939).
Feb. 24, 2017 | Tags: past weather, snow

Question: Is our warm winter more likely caused by La Nina or global warming? — Susan Biddle

Answer: Because of year-year variability and even some multi-year oscillations in patterns that drive temperatures toward above, near, or below-normal seasonal averages, it can be hard to ascribe any one season to a specific single cause. That being said, while a globally averaged warming trend due to increasing concentrations of greenhouse gases might be expected to increase the likelihood or frequency of warmer winters over time, the effect would be seen as a small upward trend in temperature added to a more largely variable signal. As for La Nina, that pattern does correlate with warmer and drier than normal winters for our part of the country, so is probably a better choice as a proximate influence on this particular winter. Even so, it is worth noting that the correlation is far from perfect, so that we sometimes have near-normal or colder than normal winters in La Nina years (it tilts the odds toward the warm side, but doesn't represent a guarantee for how the season will turn out).
Feb. 23, 2017 | Tags: climate change, el nino/la nina, winter weather

Question: Not typically hit every year by pollen allergies, particularly this early in February, but this year something is already having a field day with the sinuses. Seeing many tree ornamentals blooming so soon was wondering, with this recent run of warm weather, if the pollen count is already up high? Seems way too early but perhaps...? — Len

Answer: We had a warm January, and by the middle of February we were averaging almost 7 degrees above normal for that month. Phenology maps indicate the anomaly for early leafing plants is about 8-12 days early for our part of the country compared to 30-year average dates, so it isn't unreasonable to think you're experiencing some pollen issues a good bit earlier than usual. Pollen counts from the NC Division of Air Quality jumped into the high (and briefly very high) range for tree pollens in the days leading up to Valentine's, with the principle species listed as Elm and Juniper/Cedar/Cypress. Elm is especially known for being allergenic to some people, with Juniper and Cedar also known to have effects.
Feb. 22, 2017 | Tags: pollen, weather & health

Question: Please please answer my question. I have always known full moon is end of month. Why are we now having full moon around the middle of the month? — Patricia Pender

Answer: We're not sure how the idea that full moons should only occur at the end of months has gotten around, or exactly how pervasive it is, but we've gotten a few questions to this effect recently. Full moons have always been able to occur at any time of a month, and are not restricted to the end of months. Keep in mind that the lunar cycle is such that the moon's orbit puts it into position for a full moon about every 29.5 days, while the length of months varies, mostly between 30 and 31 days, but also with February at 28 (and sometimes 29) days. So, typically the timing of a full moon will move back (earlier) by about a day or so each month. In rare months, a full moon occurs both right at the beginning of the month and another right at the end, giving us two full moons in a single calendar month. In modern times, the second of those has come to be known as a "blue moon."
Feb. 21, 2017 | Tags: astronomy, folklore

Question: We know at WRAL you don't like to talk about humidity, but it seems pretty low these days. Is that normal for this of year? — JN

Answer: We make some mention of humidity in one way or another quite often, although we do tend to focus more on the direct measure of water vapor in the air (dew point) more so than an indirect measure (relative humidity) that depends on both the temperature and the amount of water vapor present. We have had some intervals with cool, very dry air over the region lately, but if anything we would appear to have had fairly high amounts of humidity in the form of dew points that are somewhat high at tomes to go along with the frequently warmer-than-normal temperatures that have prevailed through a good part of the winter. It is true that with temperature that run above normal, relative humidity in the afternoons may have been a little lower than they typically would be in a cooler winter, not because there is less water vapor present, but because when similar amounts of water vapor are combined with higher air temperatures, the value of relative humidity is lower.
Feb. 20, 2017 | Tags: humidity/dew point

Question: On Sunday, 2/12/2017 around 6PM. There was 0% Chance of rain on the hourly forecast. Why is there a T-storm on the radar? I hate riding my bike in the rain. — Tim

Answer: On the day in question, we had included on our television and online text forecasts the idea that a cold front moving in from the west toward evening could potentially produce some sprinkles late in the afternoon north and west of Raleigh, with a slightly better chance of sprinkles or showers over any part of the area in the early evening as the front moved through. Our web site forecast noted a 15% chance of rain late afternoon and a 20% chance. The hourly forecast precipitation chance is based on a gridded field that is partly filled by model data and by a digital forecast database. While this usually reflects the overall forecast reasonably well, there can be rare occasions when it does not, and this may have been one of those times. This kind of issue can occur with any hourly app, and we would recommend always supplementing any view of the hourly forecast probabilities with a quick review of what is written by our meteorologists in the "forecast details" section of the WRAL Weather App or by tapping the "WRAL WeatherCenter" selection in the WRAL Weather Alert App and then tapping the day in question from the 7-day forecast that appears. In the rare instances where there appears to be disagreement between the hourly information and the forecast description, we recommend giving priority to the descriptive text.
Feb. 19, 2017 | Tags: maps & codes, wral.com

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