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Mark's WEATHER BLOG |
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July 2009
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January 2009 ArchivesA Winter Storm Warning will be in effect for much of Central Texas, including the Austin area and the Hill Country, until 11:00 am Wednesday morning. The biggest threat will be from freezing rain and freezing drizzle. Snow and sleet do not appear likely this time around. As of late Tuesday afternoon, temperatures are near freezing in the Hill Country, but still above freezing elsewhere. Tuesday evening, an upper-level disturbance will slide across our area, triggering rain. With Hill Country temperatures already at, or below freezing, freezing rain is likely beginning this evening. Total accumulations in the Hill Country look to be around 0.10", with 0.25" possible in a few spots. Since the ground is still very warm, surface roadways shouldn't be much of a problem, but bridges and overpasses may ice up. Precipitation should end in the Hill Country before sunrise Wednesday, but temperatures should stay below freezing until late morning. The Austin area will stay above freezing until after midnight. However, after midnight, as temperatures approach 32 degrees, we could see light freezing rain. Accumulations should be less than 0.10" in most cases. There could be a few slick spots, especially on bridges and overpasses during morning rush hour on Wednesday. Precipitation should end before rush hour, but temperatures could remain near freezing through mid-morning. Unlike the big ice storms we've seen in the past, it's not likely that we'd have enough icing to bring down trees and power lines. As is the case so many times, Austin is right on the fence with this system. In fact, a couple of computer models have the precipitation ending just as Austin hits freezing. That would be great news for us. But, it doesn't take much ice to create a real mess around here, so let's be ready just in case. Dennis writes: "I have a 5 year old that is always asking questions about storms, tornadoes, flooding and snow. I would appreciate a recommendation on a website to visit so we can get answers to our many questions." Dennis, Here's a good place to start. http://www.education.noaa.gov/students.html It's a collection of weather-related educational sites from NOAA aimed at students of all ages. Teachers will also find a wealth of information on these web sites! -Mark In a blog entry a few days ago, I mentioned that 2008 was Austin's 3rd warmest year on record (records in Austin date back to 1854). But, overall for the entire planet, it was the coolest year since 2000. Even so, it's interesting to note that 2008 still ranked as one of the top ten warmest years since 1880. The reason for the cooling in 2008 most likely had to do with a La Nina that developed early in 2008. La Ninas (cooler waters along the equator in the Pacific Ocean) often lead to cooler global temperatures, while El Ninos (warmer waters) are often responsible for warmer years. In the map below, the red shades indicate parts of the planet that were warmer than normal in 2008, while the blue colors indicate cooler than normal conditions. Notice the blue shades along the equator in the Pacific Ocean...that's La Nina!
You can read more of this report here. We've started off 2009 with La Nina still going strong. Indications are that it could last through spring. However, a more detailed report predicts that an El Nino could emerge later this year or next, leading to another global temperature record during the next 1-2 years. Bob writes: "I watch and enjoy your segment of the news regularly. You have a clear and concise report and a friendly and relaxed style that I enjoy. As a seasonal allergy sufferer I pay particular attention to your allergy report. Your counts and the ones from others are always different. I know that your station is the only one that collects its own data, (that's why I trust yours above the others). Please tell me how to reconcile the differences I see in these reports." Good question, Bob. It's one we receive often. You're right. KVUE is the only television station in Austin, and I believe the only station in Texas, that takes our own daily pollen counts. We've been doing so for over 10 years. Even though local allergy offices do a wonderful job, and provide very accurate pollen counts, they are made available to the local media only 4 or 5 days a week. We think it's important to have a new count 7 days a week, 365 days a year...especially this time of year! Cedar Fever never takes a holiday!! So, that will account for some of the difference you see our numbers. The other reason is that most allergy offices use a machine that takes one 24-hour pollen sample each day. The machine we have on the roof of our KVUE studios takes samples from shorter periods of time throughout the day and night. A standard glass microscope slide is coated with a thin layer of grease. Our pollen machine opens and exposes a thin sliver of the slide to the air for a short period of time, allowing the pollen in the air to stick to the slide. Then, the machine closes, repositions the slide, and awaits the next air sample. That way, we can see samples from the different times of day. The sample we most often use in our weathercasts is taken early in the morning, when we typically see the most pollen in the air. That way, you're always getting "today's" pollen count, rather than an overview of the past 24 hours. Of course, there are other factors that will account for slightly different pollen counts from different sources. Several years ago, we took our machines all around town. As you might expect, the cedar count was higher in places with lots of cedar trees. Cedar Park got its name for a reason! Cities with fewer cedar trees (like Pflugerville) had lower counts. By taking our own counts each and every day, we feel that we provide our viewers with the most up-to-date pollen count available anywhere in Central Texas. I hope you agree. Thanks for the question! Mark If you've been reading my blog, you already know that La Nina is back, and it's not good news for Central Texas. Based on previous La Ninas, here specifically is what the Austin area can expect over the next few months. During the months of January through March, history shows that we can expect a 50.2% chance of below normal rainfall, only a 23% chance of above normal rainfall, and a 26.8% chance of near normal rainfall. Here's the link to the graphic. We're in "Upper South Texas" on this map: In April through June, it gets a little better, but not much. There's a 28.2% chance of drier than normal conditions, a 23.3% chance of wetter than normal conditions and a 48.6% chance of near normal rainfall. Here's the graphic: http://www.cpc.noaa.gov/products/analysis_monitoring/lanina/usdivtp/amjp1sg.gif Once we get into the summer months, a La Nina doesn't have much impact on our precipitation. With or without a La Nina, summers are typically very dry. Let's hope we can beat the odds this year. -Mark Murray
Even though the Space Shuttle isn't in orbit right now, we still have opportunities from time to time to see the International Space Station fly overhead. We'll have a beautiful pass over Texas early Saturday evening (January 17th). Because the pass happens not long after sunset, we'll be able to see the ISS from horizon to horizon. Here's when and where to look! Saturday, January 17th It'll appear brighter than the brightest star in the sky (Sirius) but not quite as bright at the planet, Venus, which has been our "evening star" over the past several months. It's bad news for Central Texas...La Nina is back. The water along the equator in the Pacific Ocean has cooled, and it will likely mean that our drought conditions will continue. Central Texas, including the Austin area, is in an exceptional drought...the worst category. Experts now say that La Nina may persist through spring and perhaps longer. During a La Nina, Texas usually has warmer and drier weather than normal. You can read the full discussion from the Climate Prediction Center here.
My good friend, Bob Rose, Chief Meteorologist over at the Lower Colorado River Authority, passed along an interesting bit of information, today. The final numbers for last year are in, and 2008 will go down in the record books as the third warmest year in Austin's recorded weather history. Reliable temperature records in Austin date all the way back to 1854, so it's worth noting that the top three warmest years have all occured in the past 10 years. 1) 2006 Average Temperature 71.6 degrees The average annual temperature for Austin (Camp Mabry) is 68.5 degrees, and is based on temperature data from 1971-2000. Arctic air is still on track to arrive in Austin on Wednesday of next week. Even though wintery precipitation still doesn't appear likely, we could see overnight lows dip into the teens. That hasn't happened in Austin (Camp Mabry or the old Robert Mueller Airport) since 1996. So far this winter, the coldest temperature at Camp Mabry has been 28 degrees. Here's a list of the coldest temperature experienced each winter for the past 20 years. All readings were taken at either Camp Mabry or Robert Mueller Airport. Readings at the old Bergstrom Airforce Base (now ABIA) would have been colder due to their unique location down near Onion Creek where cold air tends to settle overnight. So Far This Winter 28 degrees -Mark Murray Here's an update on the arctic air that I expect to arrive in Austin around next Wednesday (January 14th). As of this afternoon (January 7th), the temperature is down to -54 degrees at Dawson airport in the Yukon Territory. That's a drop of 25 degrees in the past 48 hours! The cold air is building and will soon be on the move. The U.S. based forecast model (the GFS) has the cold air surging into the northern plains early next week, but quickly slides it off to the east, with the coldest air missing Texas. This is a common error with the model, which doesn't handle the shallow cold air very well, especially a week ahead of time. The model that typically does the best is one that's based in Europe (the ECMWF). This model has the arctic air arriving in Texas late on the 14th, with another strong arctic surge on Saturday the 17th. The good news is that upper-level winds should be out of the northwest as the cold air arrives, limiting our chance for any freezing or frozen precipitation. Of course, that could change, but as of now I'm simply looking for wind and cold. In fact, this could easily be the coldest air of the winter, with a widespread hard freeze. Situations like this in the past have sent our overnight lows into the teens and 20s. Here's what I'll be watching closely over the next few days...temperatures as cold as -60 degrees in parts of Alaska and northwestern Canada!! Tonight (Monday January 5th), temperatures are already down to -40 in Fort Yukon, Alaska and are forecast to reach -60 degrees by Thursday night! Fairbanks, Alaska is forecast to reach -45 degrees on Thursday night. That's not far from the -51 degrees they recorded during the extreme cold outbreak of 1989! The coldest temperature ever recorded in Alaska? That would be -80 degrees at Prospect Creek on January 23, 1971. It looks like part of this arctic airmass will move into the U.S. next week. Even though it's too early to say if it would impact areas east of the Mississippi River, or perhaps even Texas, it certainly has my attention! Wherever it goes, low temperature records could easily be broken. If you'd like to track this cold air, you can do so on www.kvue.com. Here's the link for current temperatures in Alaska: And, here's the link for current temperatures in Canada. Pay particular attention to temperatures in the Northwest Territories, and the Yukon Territory. http://weather.kvue.com//auto/kvue/global/Region/CN/Temperature.html Once those temperatures start hitting -60 degrees, look out! -Mark Murray |
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Chief meteorologist Mark Murray joined KVUE in 1990. Ask Mark a question at weather@kvue.com.
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