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Question: New at this. I was given a meter that has MMHg and hPa. What is this and what do I use as a reference to calibrate it? — David Coltrane, Sr
Answer: The units you noted indicate you muct have received a barometer. This measure atmospheric pressure, which can be stated in any number of different units. The ones you listed are "millimeters of mercury" and "hectoPascals." You can work out the appropriate factors for converting between various common pressure units by knowing that standard sea level pressure can be given as 29.92 inches Hg = 1013.25 millibars = 1013.25 hPa = 760 millimeters Hg = 14.7 pounds per square inch. Notice millibars and hPa are the same numerically. There's also a handy pressure units converter in the bottom right panel of the page at www.srh.noaa.gov/ama/?n=conversions.
Since the more important factor with a home barometer is the trend over time (rising/falling/steady, and how rapidly any changes occur) as opposed to the precise pressure value, you can make a good ballpark calibration by checking a recent reading from a nearby airport and adjusting your unit to the same value. The pressure you should attempt to match would be the value listed as either "sea level" or "altimeter setting." You can find such listings in the "current conditions" section of our weather web site, where the pressure is given in inches of mercury.
Nov. 6, 2014 | Tags: instruments, wral.com
Question: Why is the forecast high shown to the right of the forecast low? I find this confusing since the low for the day occurs in the AM for that day. — Don Thomas
Answer: We assume you're asking about the appearance of our 7-day forecast with the "tubes" design. The idea of having the low shifted a bit to the left within the tube for a given day was to indicate exactly what you mentioned, that is that the low temperature would typically occur around sunrise, while the high would usually be reached in the mid-afternoon. With that in mind, scanning the 7-day image left to right would take you through the expected temperature extremes in order, from afternoon high to next morning low to that afternoon high to next morning low, etc. The setup is a little different for the "vertical" 7-day forecast on our web site. There, each line shows the high for the day on the left and the upcoming "overnight" low that corresponds to the "overnight" forecast tab within the box that contains the written forecast text. In this case, the low does indeed occur (typically) around daybreak the next morning.
Nov. 5, 2014 | Tags: maps & codes, wral.com
Question: How many tornadoes have we had in North Carolina this year? — Josiah
Answer: All we can offer for now is a rough estimate that will likely be revised as more complete data is collected and posted by the Storm Prediction Center and National Climatic Data Center. Tornado reports initially come in the form of a product called local storm reports, for which a very up to date archive is readily available. However, in some cases these preliminary reports turn out to have been due to non-tornadic storms, or there may be several reports that all arise from a single tornado, so that the initial number of reports is usually an overestimate. Using that value, there were 40 tornado reports in NC for January through October 2014. The Storm Prediction Center applies a ratio of .85 as a rough correction factor to reduce potential duplicate reports, which would give an estimate of 34 tornadoes. A more accurate, final count for our state for 2014 will be available from SPC and NCDC by sometime in the spring of 2015, as by that time tornado damage survey reports from local NWS offices will have been collected and entered into databases that reflect, as near as is possible, the actual number of confirmed tornadoes.
Nov. 4, 2014 | Tags: past weather, tornadoes
Question: Once before I lost the hourly forecast brought to us by Wake Forest. This window is gone again. How do I get the hourly forecast back? I Use the graph to plan my day. — Elaine
Answer: The hourly forecast through our web site can be accessed via a link (in blue letters) on the main weather page right above the 7-day forecast, or via link fromt he "Weather resources" page, or directly at www.wral.com/hourly_forecast/1005691/.
Once you reach this page, you can type in any zip code or city, state combination to retrieve the hourly forecast for that location. If you prefer to keep that info in a separate window, you can right click on the link and request that it be opened in a new window. Also, if you are a registered user of our web site, once you switch the forecast to a town or zip code of your choice, it should default to that location the next time you return to the site.
Nov. 3, 2014 | Tags: maps & codes, wral.com
Question: Why don't you post backyard weather stations on your show or online? It would give you and everyone else a better view of the up to the minute weather. — Jeff C
Answer: While the temperature maps we present on the web site are based on observations from official FAA and/or NWS observing sites, we do actually use some personal weather stations on some of our on-air weather maps, mainly those that are zoomed in rather tightly around central NC and include places like Durham, Clayton and Cary. While some of these sites are personal weather stations, they have gone through some siting and data quality checks to try and make them as consistent as possible with those at airports and other government sites. There is also a way to see many more personal stations through our web site, by going to our "Weather Resources" section and scrolling down to "personal Weather Stations." Clicking that link brings up a densely populated Weather Underground map with personal stations in the foreground and a radar map in the background. Data shown on the station plots can be changed by clicking the gear/sprocket symbol next to "Weather Stations" label to the upper right of the map.
Nov. 2, 2014 | Tags: maps & codes, wral.com
Question: We had a strong weather system and cold front headed our way back on October 14th, and surface maps predictions showed the front passing through Triangle by 8 a.m. the next day. However, the WRAL forecast and other public forecasts for the day or so following the front passage showed winds out of the Southwest. I thought most cold fronts brought winds from NW or NE. — Dave Crtts
Answer: Your question does a good job highlighting the fact that while a lot of behavior with weather systems follows reasonably well-behaved patterns, there are substantial exceptions to almost any general rule, and the atmosphere often evolves in a sufficiently complex manner to make generalizations difficult. It is true that most cold frontal passages here result in a shift to winds with a northerly component, but there are situations that diverge from that behavior.
In the case you were asking about, an initial frontal passage was followed by a sharpening upper level trough that dug into a closed upper low positioned to our northwest and helped to generate a new surface low and trough that stretched south across KY and TN, ahead of which winds rapidly shifted to the west and southwest for our area. Situations like this often result in temperatures that only back off a little in the wake of the initial front. In this case, a high of 79 on the 14th was followed by highs that remained in the low to mid 70s the next several days, due to the systems west of us preventing a significant intrusion of colder air.
Nov. 1, 2014 | Tags: fronts & airmasses, general meteorology, past weather
Question: What happened to the map that would give you the weather over the past hour in 4 min intervals? With the new map, I can't tell the direction of storms. — Gloria Ripperton
Answer: We can't quite be certain, but it sounds as if you're asking about the radar lapses we've made available for our Dual Doppler 5000 and Fayetteville Doppler radars, or perhaps the interactive iControl radar display, which uses a composite of regional National Weather Service radars. In either case, those products are available in our "Map Center." You will see a link to that section near the upper right corner of our main weather page. Once you are at the Map Center page, you can choose between the DualDoppler 5000 or iControl. In the DualDoppler 5000 section, you will see tabs to choose between a still image, a one-hour loop (the kind you asked about) and an 8-hour loop, as well as a menu to choose different views zoomed to various poarts of our viewing area. In iControl, just press the "play" button below the map.
Oct. 31, 2014 | Tags: weather radar, wral.com
Question: Did it rain in Goldsboro during the week of October 18th-25th? — Angela W. McCoy
Answer: That week fell within a generally dry period for much of our region, and rainfall records from stations in the area, along with archived radar rainfall estimates available at water.weather.gov/precip/, appear to indicate no rain fall in the Goldsboro area during that period, with the most recent prior rainfall there reported on October 15th.
Oct. 30, 2014 | Tags: cool sites, past weather, rain
Question: What time was the eclipse on 10-21-2014? — Barbara Turner
Answer: For the Raleigh area, that partial eclipse of the sun actually occurred on 10-23-2014, and began at 5:59 PM for the Raleigh area, with the greatest coverage of the sun by the moon occurring at 6:29 PM, just a minute prior to sunset. We usually provide information about eclipses and similar events on our web site, our WRAL Weather Facebook page and sometimes within our on-air weathercasts, in the days leading up to the event. In addition, you can find a wealth of eclipse-related data on the web at sites like eclipse.gsfc.nasa.gov/eclipse.html and www.mreclipse.com.
Oct. 29, 2014 | Tags: astronomy, cool sites
Question: Any chance we had a very small earthquake in the area around 12:30 on Thursday, October 23rd? I'm in West Cary and it felt like we had a small tremor. I guess it could have been construction in the area (or too much coffee!) — Dawn Toman
Answer: We're going to have to lean toward the construction and/or coffee solution on this one! We haven't received any other questions or reports to that effect, and a check of a USGS database of recent earthquakes of magnitude 2.5 or higher didn't show anything detected for the eastern U.S. on that day or within a couple of days either side. You can check that site if you ever feel what you think may have been a quake, by going to earthquake.usgs.gov/earthquakes/map/ and zooming the map in enough to get a good view of NC (or wherever you're interested in). You can also open the "settings" page by clicking the sprocket/gear icon in the upper right, and adjust how long a window of time to cover, as well as the minimum magnitude of quakes to display.
Oct. 28, 2014 | Tags: cool sites, earthquakes/tsunamis
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Published: 2007-10-09 14:40:00
Updated: 2014-06-24 16:06:51
Triangle Area Special Offers
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