Ask Greg

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: It's hard to know exactly what you might mean by "things" in this question. If one had to reduce a cloud to two physical components, perhaps you could say clouds are, at their most basic, made up of water and cloud condensation nuclei, as typical clouds in the atmosphere are composed of water droplets or ice crystals, and the tiny particulates of various kinds that can serve as nucleation points upon which the water can condense (as a liquid droplet) or deposit (as an ice crystal) given the correct combination of humidity, temperature and in some cases vertical motion.
Nov. 20, 2009 | Tags: clouds, general meteorology

Answer: There isn't a real obvious link back to an ancient Latin or Greek term as is the case with many modern words, but some etymology resources do cite a Greek word, aithria, that today would mean "good weather" and a later, more general term for weather, kairos. It isn't clear whether those words led in some direct way to later European terms like the Old Saxon word wedar, the Old Norse term vethr, or the Old High German and Old English words wetar and weder, but one can certainly relate that group of terms pretty well to the current form of the word in English, along with the current German wetter and Dutch weder.
Nov. 19, 2009 | Tags: general meteorology, past weather

Answer: If you take eight years literally and go back that far from the date this answer is being added to our database, then we have not fallen into the single digits at all during that span. However, if you reach back a little farther, the most recent occurrences of single-digit lows at the airport were in January 2000 in the wake of a major snowfall, when the temperature dipped to 1 degree Fahrenheit on the 28th and 7 degrees on the 29th.
Nov. 18, 2009 | Tags: cold, past weather, records/extremes

Answer: You don't say what part of our viewing area you live in, but as an example you can use our Almanac page and the "Get Historical Data" feature to begin your search with any day during that fall. Once you are there, click the "monthly" view, and you can scroll to the bottom and scan through the "Thursday" reports to see what the observed high, low and rainfall values were, then use the "next month" link to move ahead through the fall months. If you see a Thursday that interests you, you can click the date and go to a more detailed hourly listing for that day. Finally, if you think there is another location that would be more representative for you than RDU, you can change weather stations as well.
Nov. 17, 2009 | Tags: cool sites, past weather

Answer: For specifics on your situation, it would be a good idea to have a licensed electrician or grounding specialist take a look and recommend the best course of action. More generally, it is worth noting that if there are a number of trees immediately nearby that are much taller than the mast you installed, that may indeed reduce, but not eliminate the chance that it will be struck. In addition, it is not the case that grounding the unit makes it "attract" lightning. Instead, what you are trying to do in grounding it is provide a path for the lightning discharge to follow that goes around rather than through your home in case a strike does occur. One of our engineers recommends these web addresses as good sources of more information: lecglobal.com/learn/lightning-101/ and lecglobal.com/info/tech-papers/preventing-direct-lightning-strikes.pdf.
Nov. 16, 2009 | Tags: cool sites, lightning, preparedness

Answer: Yes, to do so click on the "e-mail alerts" link near the very bottom of most pages on our site, and it will take you to a management page where you can select from a variety of weather and news feeds to be delivered to your e-mail address. Note that you do need to be a registered user of WRAL.com, and logging into your account provides you with the access needed to select and deselect your desired e-mail alerts.
Nov. 15, 2009 | Tags: wral.com

Answer: Standard sea level pressure can be expressed in a number of different ways. For example, 14.7 pounds per square inch, 760 mm Hg, 29.92 inches Hg, 1013.25 millibars, 101.325 kiloPascals, 1 atmosphere and so on. Since they all represent the same pressure, you can use those values to convert between units.
Nov. 14, 2009 | Tags: general meteorology, normals

Answer: Unfortunately a fireball sighting log hosted by the American Meteor Society has not been updated since late October due to problems with the reporting form. Based on the time of year of your reports, and the overall description, it sounds as if you and your sister witnessed a fireball (very bright meteor), quite possibly associated with the Taurid meteor shower. On the following evening, a Taurid fireball was widely seen in California, and some photos and videos were captured, which you can peruse in the "Weekend Fireballs" section at http://www.spaceweather.com/archive.php?view=1&day=09&month=11&year=2009.
Nov. 13, 2009 | Tags: astronomy, cool sites

Answer: As you imply with your question, it is certainly possible to have below normal rainfall while receiving rain in trace or rather small measurable amounts fairly often. This year has fit into that category to some extent. Through the end of October, we had six months with above normal number of days with at least one hundredth of an inch of rain, while four months were below normal. In total during that time, 104 days brought measurable rain, when the normal for the first ten months of the year is 95.
Nov. 12, 2009 | Tags: normals, rain

Answer: The answer all depends on how much water vapor is in the air already, as indicated by the dew point. Water can evaporate as long as the temperature of the air above it or surrounding it (in the case of suspended drops) has a dew point lower than the temperature of the water. If the water and air are at the same temperature, then as long as the temperature is higher than the dew point, water can evaporate. On the other hand, water vapor will condense into liquid water if the temperature of the air containing the water vapor is cooled to the dew point or below, or can condense onto an adjacent surface if that surface is cooled to the dew point or below.
Nov. 11, 2009 | Tags: general meteorology, humidity/dew point