It’s a photo that’s been circulating around the interwebs: a spectacular display of halos, arcs and lines all around the sun, taken by Joshua Thomas in Red River, New Mexico on January 9. We’ve all seen halos around the sun and moon, but I bet you’ve never seen anything like this!
One of the subjects meteorologists study in college is optical physics in order to explain things like halos, but it took an expert physicist in atmospheric optics to identify the many halos here. Dr. Les Cowley (it’s misspelled on the picture) from Atmospheric Optics (www.aoptics.co.uk) has diagrammed the picture to tell us what’s what.
Halos are formed when millions of ice crystals are present 3 to 5 miles above the ground. All ice crystals are near perfect hexagons. When the sun’s rays pass through them, the rays are reflected and refracted, resulting in halos. The smallest halo around the sun is the most common: it’s a 22 degree halo, meaning the angle from the center of the sun to the halo is 22 degrees. It’s produced when the ice crystals are tilted 60 degrees to one another. An even larger halo, a 46 degree halo, is rare and produced when the ice crystals are tilted 90 degrees to each other. (Geometry DOES come in handy sometimes!)
So what caused all these halos and arcs in the sky? We see ice crystals in cirrus clouds all the time, but rarely halos like this. Sometimes in areas where ski resorts make snow using “snow cannons”, ice crystals from these cannons drift through the air, producing halos. It’s sort of like when you spray water from a hose and see a rainbow. Ice crystals are sprayed into the air, creating halos. There’s a ski resort in Red River, NM that does, indeed, make snow. The sun is also low in the sky in the photo, indicating maybe some ice crystals didn’t need to be high in the atmosphere to catch the sun’s rays. Perhaps they were making snow in Red River on January 9.
But unusual halos and arcs can be seen even when snow making machines aren’t nearby. Just last Friday in Dallas, a sun dog and parhelic circle were seen in the cirrus clouds above!
Photo courtesy of Terry Pace
Folklore says when a halo is seen around the sun or the moon that rain is on the way. What halos indicate are the presence of high, thin clouds made of ice crystals. Sometimes it rains afterward, sometimes it doesn’t. But if you’re near a ski resort that will be making snow, keep the camera handy for any unusual halos, and maybe your picture will go viral, too!
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Happy New Year! As we head into 2015, meteorologists are often asked about the weather outlook for the year ahead. It's frustrating that the science of meteorology is still so young, long term predictions for rain or snow showers are impossible, but astronomy is a much older science and a lot more predictable, so mark your calendars for this year’s meteor showers! (Don't call them "shooting stars" or you'll make an astronomer angry!)
As always, viewing is best away from city lights, generally after midnight. While the meteors radiate from certain constellations, they are visible anywhere in the sky.
NOW- Jan 10th; peak 3rd-4th - Quadrantids Meteor Shower is an above average shower, with 25 - 40 meteors per hour at its peak. We're already getting reports of them. A nearly full moon will make it tough to see all but the brightest meteors on peak nights, but watch from midnight until dawn; they'll radiate from the constellation Bootes. Quadrantids can produce bright fireballs if you’re away from city lights.April 16-25th peak: 22nd- 23rd - Lyrids Meteor Shower. The Lyrids is an average shower, with about 20 meteors per hour at its peak. Watch for these any time after sunset, generally radiating from the constellation Lyra. Like the Quadrantids, the Lyrids can produce fireballs.
April 19th-May 28th, Peak: May 6th, 7th - Eta Aquarids Meteor Shower is an above average shower, produced by dust left behind by Halley's Comet! Expect to see up to 30 meteors per hour during peak days, radiating from the constellation Aquarius. If you're lucky enough to be in the Southern Hemisphere at this time, you could see up to 60 meteors per hour. In both hemispheres, watch for streaks of light but few fireballs. July 21-August 23rd, Peak: July 28th, 29th - Delta Aquarids Meteor Shower can produce up to 20 meteors per hour, radiating from the constellation Aquarius, like the Eta Aquarids. They will be low in the sky and are usually faint without persistent trains or fireballs.
July 13-August 26th: peak August 12th, 13th - Perseids Meteor Shower. This is probably the most well known meteor shower, producing up to 75 meteors per hour at its peak with a large number of bright meteors. With no full moon during the peak nights, this year could offer a great show. They radiate from the constellation Perseus.
October 4-Nov 14th Peak: 21st, 22nd - Orionids Meteor Shower. The Orionids can produce up to 25 meteors per hour on peak nights. There have been years where over 50 meteors per hour were visible. Orionids are also produced by dust grains left behind by comet Halley, radiating from the constellation Orion.
October 19 -December 10, Peak November 11th,12th - Taurids Meteor Shower. The Taurids produce only about 5-10 meteors per hour, radiating from the constellation Taurus. The Taurids, both in the Northern and Southern hemispheres, produce many fireballs.
November 5-30th, peak 17th, 18th - Leonids Meteor Shower produce up to 15 meteors per hour on peak nights, radiating from the constellation Leo, producing bright meteors with a lot of persistent trains.
December 4-16th: peak 13th, 14th - Geminids Meteor Shower. Mark your calendar for this one: the Geminids is the biggest of all the meteor showers, producing up to 120 meteors per hour on peak nights! These meteors show up in different, intense colors, too! The Geminids radiate from the constellation Gemini, they are slow and don't often have persistent trains.
December 17-25rd peaks: 22nd, 23rd - Ursids Meteor Shower produce about 5-10 meteors per hour, radiating from the constellation Ursa Minor.
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Here in Texas, we know the weather won’t cool down (and stay cool) until our State Fair ends. Other cities follow local weather “folklore” too: Are the caterpillars extra wooly this year? Are the pecan and oak trees producing a lot of nuts and acorns?
If you split a persimmon seed, do you see a knife (cutting cold with ice), a spoon (digging out of snow), or a fork (a mild winter that provides lots to eat)? What does a spork mean, then? Are your pets getting extra furry … or shedding? What does the Farmer’s Almanac say?
Our weather folklore originated in the New England states when the first settlers observed certain occurrences, then related it to the weather of the season. While some folklore is correct (red sky at night, sailor’s delight, red sky at morning, sailors take warning), a lot of the caterpillar-pecan-acorn-persimmon forecasts have not merited awards for accuracy. Sorry to say, neither has the Farmer’s Almanac. And, while the State Fair in Texas has ended, Dallas will still warm to near 90 on Sunday!
Last week, the Climate Prediction Center issued the official Winter Weather Outlook. The outlook is based, among other things, on what is happening in the Pacific Ocean. Meteorologists are watching for a developing El Niño, when water temperatures in the eastern equatorial Pacific start warming. Changes in ocean temperatures in the Pacific influence weather patterns around the world; ocean temperatures in the Atlantic influence global weather too, just not as much. At this time, there is no El Niño, however, there is a 67 percent chance of a weak El Niño developing by the end of the year.
What does that mean for our winter? The best news of all: For many of you who suffered a bitterly cold and snowy 2013-2014, this winter is not expected to be a repeat. For the Northeast and west of the Rockies, a warmer-than-average winter is forecast. For the southern Plains, Texas, Gulf Coast, Florida, and the Carolinas, temperatures are expected to be cooler than average. For the Midwest, Great Lakes, Rockies, and Mid-Atlantic states, average temperatures are forecast.
Regarding precipitation, because this is a weak El Niño, the California drought is likely to continue, even with a wetter than usual winter expected in the southern parts of the state. For the desert Southwest, Texas, Florida, and the Carolinas, expect above-average precipitation. The Mid-Atlantic and coastal areas of the Northeast and New England can expect a slightly wetter than average winter. The Pacific Northwest, Great Lakes, and upper Midwest can expect a drier than average winter. Everywhere else from the Central Pacific to the Rockies, Central Plains, and Tennessee Valley can expect an average winter, precipitation-wise.
Keep in mind, these forecasts are for winter averages, and, while Chicago is expecting a drier and slightly warmer winter than average, there is always the possibility of a couple of heavy snow days and a few bitterly cold days. And, in Florida, where they expect a cool and wet winter, there will be some sunny, warm days, as well. Who knows, maybe travel this winter will be the opposite of last year, with those in the South heading north to “warm up”!
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It was just two weeks ago we were experiencing the “return of the Polar Vortex” in the middle of summer, a highly unusual occurrence, or so we thought. Now another round of welcome cool air is bringing much needed relief for the eastern half of the nation. Is it another Polar Vortex? Nah, this time, it’s cool air from Canada.
Listen to a forecast on TV or read a forecast online, and you’ll often hear or see the words “a cold front from Canada is responsible for this summer season cold blast.” Our Canadian friends sometimes get a little miffed over that. Certainly not all of our cold outbreaks originate in Canada. The Polar Vortex cold originates—you guessed it—over the Polar Regions. Sometimes our winter cold outbreaks originate over Siberia and are simply passing through Canada on their way to the states. In the summer, most of us don’t really care where the cool air comes from, we’re just happy to see it bring some shortterm relief from typical summertime hot temperatures.
During the summer, when a high pressure system stalls over the U.S. for several days or even weeks, it usually means a heat wave will ensue in that region (this is obviously not true in the winter). For the last several weeks, a large high pressure system has been sitting over the Rockies, baking Phoenix, Las Vegas, Salt Lake City, Reno, Tucson, and even parts of Idaho and Oregon. That’s not unusual for the desert southwest, but it is rather unusual for the northern Rockies.
Last week, that hot dome of high pressure spread eastward, bringing triple-digit heat and heat advisories to Little Rock and Memphis, through Oklahoma, all the way down to south Texas, and along the Gulf Coast states. Thanks to another blast of cool air, that heat wave-producing high pressure system has now weakened, and temperatures for a good part of the nation have once again cooled to below average levels. For instance the Dallas/Fort Worth area will be around ten degrees below average the rest of the week, Chicago and much of the Great Lakes will likely have high temps in the 70s, and Baltimore and New York City barely make it into the 80s through week’s end. Even as far south as Greenville, SC and Charlotte, NC highs will only reach into the low-mid 80s.
Unlike the return of the Polar Vortex a few weeks back, this blast of cool air originates in Canada, right around the Northwest Territories and Nunavut, but not quite to the Polar Regions. Some people might blame our neighbors to the north for our cool blast, but the majority of us will thank them. Either way, enjoy the second recent blast of cool air this summer, but don’t think this necessarily has any bearing on how cold next winter may be!
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