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Looking Back: February 10, 2009 Severe Weather Outbreak

Damage in Lone Grove Oklahoma | Photo taken by National Weather Service Norman, OK

Damage in Lone Grove Oklahoma | Photo taken by National Weather Service Norman, OK

Damage in Lone Grove Oklahoma | Photo taken by National Weather Service Norman, OK

Six years ago today at about this time I was heading north on Interstate 35 for what would become my first real significant storm chase. I had been chasing since the fall of 2008 on mediocre storms here and there but February 10, 2009 would be my first day dealing with the worst of what mother nature had to offer. It’s a day I remember well six years later and still look back on.

The February 10, 2009 severe weather outbreak was well forecasted by the Storm Prediction Center several days in advance. A negative tilt shortwave centered over New Mexico during the afternoon hours bringing strong lift and upper level dynamics to Central Oklahoma south into North Texas. Meanwhile a powerful low level jet with screaming southeast winds just above the surface helped pump in rich moisture straight from the Gulf of Mexico. Reminiscent of an April severe weather setup Mother Nature didn’t care that it was early February. Just after lunchtime the first tornadoes touched down in the northern Oklahoma City metro near Edmond where one strong tornado caused quite a mess but fortunately no fatalities.

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By the late afternoon additional thunderstorms were developing in our target zone near Bowie, Texas. These storms were initially elevated in nature and struggling to strengthen with powerful upper level winds blowing the updrafts over. One discrete thunderstorm eventually developed a sustained updraft near Bellevue, Texas where a rotating wall cloud rapidly developed. This storm was quickly moving northeast and we struggled to keep up with it as it continued to intensify and come closer to producing a tornado. With evening twilight starting to wane the storm produced its first tornado just northeast of Ringgold, Texas near the Red River. We lost the storm as it crossed the river due to the lack of a suitable river crossing and the fast storm speed.

The bellevue storm continued to move northeast after the sun set. With a strengthening nocturnal low level jet a powerful, long-track tornado developed on the Red River and continued as the storm moved northeast into Love County, Oklahoma. At 7:30 PM on February 10, 2009 a large and violent tornado moved northeast into the city of Long Grove, Oklahoma. The sun had set over an hour before and the tornado was obscured by rain and darkness. It finally became visible as it moved into Lone Grove with power flashes backlighting the tornado. Eight individuals tragically were killed by the tornado with over 45 folks injured. The tornado ended up traveling 37 miles over the course of 57 minutes from the Red River northeast through Long Grove to just north of Ardmore where it crossed Interstate 35. The tornado was mostly wrapped in rain and invisible in the night sky but the damage it left was most certainly visible.

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This weather radar look at the storm was taken moments after the tornado had moved through Lone Grove. The radar, located in Oklahoma City, was nearly 90 miles away from the storm and looking around 6,000 feet above the ground. Even with that elevated height a strong rotational couplet and ‘donut hole’ known as a Bounded Weak Echo Region (BWER) was clearly visible. This tornado would be the one and only one to claim a life that night. Shortly after the tornado crossed Interstate 35 it dissipated and the storm was overtaken by a squall line. That would be the last tornado in Oklahoma for the event.

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While the show was starting to wind down in Oklahoma it was just ramping up in Texas. After storms struggled to develop most of the day the upper level forcing finally arrived and caused a squall line to rapidly fire about 50 miles west of Interstate 35. By 9:30 PM the squall line extended from southern Oklahoma south into North, Central, and South-Central Texas. Damaging straight-line winds and large hail were the widespread threats however several brief tornadoes did occur including one in the D/FW Metroplex. Several injuries were reported from flying debris caused by the strong winds.

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While today’s weather will be calm and sunny the severe weather outbreak on February 10, 2009 is a clear reminder to all those who inhabit Oklahoma and Texas that severe weather can and does occur outside the peak spring season. Now is the time to develop and practice a severe weather safety plan with your family. Taking the time while the weather is nice to practice your plan means you’ll be ready once severe weather returns to the state. Dealing with storms is just a part of living in Texas just like earthquakes are a part of life in California. You prepare, you practice, and you enact your plan if the time comes. The point is that you know your plan ahead of time instead of trying to come up with one ten minutes before a tornado hits your location.

Minor Relief In New Drought Monitor for Texas

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The National Drought Mitigation Center released their weekly update this morning. There has been minor improvement in all drought categories with this update. The most noticeable reduction is over the Texas Panhandle where minor drought relief was noted after the significant winter storm last week. The exceptional drought designation has been reduced but severe to extreme long-term drought conditions remain evident. Extreme to exceptional drought conditions continue across Northwest Texas extending southeast into western North Texas and the D/FW Metroplex.

We note a sharp cutoff between Fort Worth and Gainesville where the drought goes from the extreme category down to abnormally dry to moderate drought conditions.

Much of East and Southeast Texas remains drought free along with the Rio Grande Valley and Far West Texas. Widespread moderate to severe drought conditions continue across Central Texas into the Hill Country and South-CEntral Texas.

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As far as rain chances in the foreseeable future most of Texas will remain in a warm and dry pattern for the next five days. After today temperatures will really warm up across all of Texas. Our next chance for widespread precipitation across Texas looks to be next Thursday and Friday.

Widespread Rain and Heavy Snow Develops Later Today

A complex and busy weather day is setting up across Texas as we face a multitude of weather hazards as an upper level low moves into our state. We’re dry this morning but we’ll start to see precipitation develop this afternoon and increase in coverage/intensity tonight. Most folks will see precipitation tonight and on Thursday. A high-end winter storm is now forecast across the Texas Panhandle and South Plains where the western Panhandle and northwest South Plains could see up to a foot of snow. 3 to 8 inches of snow is expected across the central Panhandle into South Plains including Lubbock and Amarillo. 1 to 5 inches of snow will be possible across the eastern Panhandle and eastern South Plains into Rolling Plains. 1 to 4 inches of snow is expected in the Permian Basin and Trans-Pecos into the Davis Mountains.

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This winter storm will feature several differences compared to the past few events this month. The first is we will not be dealing with a winter mix. It will either be rain or snow because of a cold core upper level low. Temperatures above the surface will be quite cold versus our previous events where we had a layer of warm air a few thousand feet above the ground. Because we have such cold air moving across parts of Texas associated with the upper level low it will be imperative to monitor the track of this low. Areas under this low may end up changing over to a wet snow even if surface temperatures are in the mid 30s (above freezing). Those warmer temperatures would keep roads just wet but would allow for accumulation of snow on grassy surfaces. Unfortunately these cold core upper level lows are one of the most difficult to deal with in a forecast. For that reason we could end up having to deal with major forecasts changes today across some areas. Right now the forecast for Graham is mainly rain with a little snow mix. If temperatures end up being 2 degrees cooler like some models are saying there could be upwards of 5-10 inches of snow. I’m not saying Graham or western North Texas will get that much snow if things turn colder but there is a lot of moisture to work with and if we end up with colder temperatures we could easily go from a cold rain to a major winter storm in parts of Northwest and western North Texas. That’s why you need to check back for forecast updates since if it looks like its going to be colder than there will be some big changes to the forecast.

With all that said here is the current snow accumulation forecast from the National Weather Service. These numbers are just a forecast and with the many factors going into the forecast I do expect there will need to be adjustment in the snow forecast throughout the day so this graphic will change somewhat.

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In fact here’s an updated accumulation forecast for the Texas Panhandle issued shortly after I made the comprehensive snow graphic. Do note that we’re talking about 6-12 inches of snow across much of the Texas Panhandle including Amarillo. That’ll no doubt cause major problems on Interstate 40 and most roads by tonight and on Thursday.

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Here’s the graphical representation of precipitation chances for the state today, tonight, and on Thursday. We’ll start seeing precipitation increase early this afternoon across the Texas Panhandle, northwestern South Plains, south into the Permian Basin, Concho Valley, and South-Central Texas. By this evening we’ll see a large area of rain move into North and Central Texas while snow increases in coverage and intensity across the Panhandle, South Plains, Permian Basin, and Trans-Pecos. On Thursday most of the state will experience precipitation as the upper level low is right over the state.

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Central Texas, South Texas, East Texas, and Southeast Texas will all experience beneficial rains beginning tonight and continuing into Thursday night with widespread accumulations of 0.75″ to 2″ of rain. No severe weather or winter weather is expected in these areas but do expect a cold and wet couple of days ahead. Here’s a look at forecast liquid precipitation forecast through Friday for Texas. This includes rain accumulations and the liquid equivalent of snow accumulations. The image is quite large so you’ll likely need to enlarge it and zoom in to your location.

2015-01-21_4-44-12Finally for a more detailed look at the precipitation’s timing here are a series of graphics from the 06Z North American Model. While the radar may not look exactly like this later today it gives a good idea of the general evolution of the storm system. Timestamps are in the top-left corner of the graphics and are in central time.

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06Z NAM – Simulated Radar at 12 PM Today

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06Z NAM – Simulated Radar at 3 PM Today

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06Z NAM – Simulated Radar at 6 PM Today

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06Z NAM – Simulated Radar at 9 PM Today

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06Z NAM – Simulated Radar at 3 AM Thursday

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06Z NAM – Simulated Radar at 6 AM Thursday

 

 

How Fog Forms!

With quiet weather and several mornings in a row of fog I thought today would be a good time to type up our next Weather Wednesday article! These articles help explain interesting weather phenomena. Because we’ve had so much fog this week I thought you might be interested in knowing how fog forms and why!

Let’s start off by explaining why we’ve been dealing with fog this week. To do that I picked up a graphic depicting weather balloon data from Tuesday morning in Fort Worth. This is when very dense fog had the airports socked in and made for a nasty day to be flying.

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This type of graphic is called a SKEW-T and would normally display the following data: air temperature, dewpoint temperature, wet-bulb temperature, wind direction, and wind speed among other data in a 2D representation of a 3D environment (altitude). With that said I’ve removed all but the air temperature and dewpoint temperature since that’s all that we really need for this explanation. I could have left the winds in for data but it’s just easy enough to say that calm or nearly calm winds are best for most types of fog to form.

The type of fog we’ll be talking about is Radiation Fog. No that does not mean you’re being radiated by toxic fog. Per the National Weather Service this type of fog forms at night under clear skies with calm winds when heat absorbed by the earth’s surface during the day is radiated into space. As the earth’s surface continues to cool, provided a deep enough layer of moist air is present near the ground, the humidity will reach 100% and fog will form. Radiation fog varies in depth from 3 feet to about 1,000 feet and is always found at ground level and usually remains stationary. It goes without saying this type of fog can reduce visibility to near zero as some of you have found out this week.

You can see on the SKEW-T (above) that the dewpoint temperature and air temperature come together in the lowest few hundred feet of the atmosphere. Above that the air temperature quickly increases and the dewpoint temperature decreases. That’s a pretty strong inversion but you may know it better as a cap. This cap kept cooler/moist air confined to the lower atmosphere and helped fog form. You may also notice this type of inversion when smoke has a tendency to stick closer to the ground instead of rising. We’ve had a fairly stagnant weather pattern this week which has kept surface winds light and our air fairly still. Once the sun rises and begins to warm the atmosphere fog will usually dissipate as humidity levels drop. The opposite occurs at night when the surface or low levels of the atmosphere are moist. That can happen after rain saturates the soil or when frontal boundaries are in the area resulting in one airmass at the surface with another air mass a few thousand feet above it like in the SKEW-T I posted with this blog. Here’s a great photo from Justin Terveen (an amazing photographer) showing the dense fog in the lowest few hundred feet of the atmosphere. Above it was nothing but clear skies! This photo was taken on Tuesday in Dallas.

Here’s another photo this time from an aircraft flying above D/FW. Those buildings are actually all you can see of Downtown Dallas. Everything else is shrouded in a few hundred feet of dense fog. Most commercial aircraft flying today have the ability to continue operations in dense fog. However airport operations will still be delayed quite a bit since they’ll only be able to operate with runways featuring specialized equipment. The same goes for aircraft and cockpit crew. That explains why some flights got in yesterday morning while others were either cancelled or diverted.

Finally there are other types of fog include Advection Fog, Upslope Fog, Ice Fog, Freezing Fog, and Evaporation Fog whichall occur under different weather and environmental conditions. We don’t usually deal with upslope or ice fog in Texas but we do have to deal with freezing and evaporation fog on occasion. Freezing fog is simply fog that occurs while surface temperatures are below freezing. If dense enough it can act like light freezing rain and deposit a thin layer of ice on objects. Evaporation fog typically occurs here in Texas when are lakes or other bodies of water are warm with a very cold airmass in place. WAn example would be when our low temperature dips to 17 degrees fahrenheit but a lake temperature is still closer to 50 degrees fahrenheit. In that case you’ll see evaporative or mixing fog form just above the water’s surface. You can also see something similar occur when air inside a freezer condenses (turns to fog) when you expose it to the warmer air outside the freezer.

November 20th Texas Drought Monitor

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As of this week nearly a third of Texas was completely out of drought conditions. That’s the highest number we’ve seen in at least a year. While Southwest Texas and extreme Southwest Texas are not in drought conditions a majority of the state continues to experience a long-term drought. The worst drought classification currently resides over western North Texas and Northwest Texas where an exceptional drought continues. While snow did fall on Sunday across parts of the region the liquid equivalent was less than a tenth of an inch which is barely a drop in the bucket. Moderate to severe drought conditions continue across Northeast, Central, and South-Central Texas plus the Hill Country and Panhandle. The good news is we’re expecting at least one inch of widespread rain to fall over North Texas by this weekend which will fill a small hole in a very large crater. It’s better than no rain though. Here’s a summary that accompanied this week’s Texas drought monitor.

Southern Plains and Texas
Bitter cold — albeit dry — weather resulted in no change to the drought depiction except along the Texas Gulf Coast. Temperatures averaged 15 to 25°F below normal for the week, with some shallow snow noted over northern portions of the region at the end of the monitoring period. Despite the frigid, mostly dry conditions, some Abnormal Dryness (D0) was reduced along the southeastern coast of Texas where rainfall totaled locally more than 2 inches. Short-term drought remained most intense (Exceptional Drought – D4) along the Texas-Oklahoma border west of Wichita Falls, where 90-day precipitation has totaled less than 50 percent of normal. In contrast, many of the long-term drought areas (“L” designation) from Texas into Colorado have received above-normal precipitation over the past 90 days, but are still wrestling with the impacts of longer-term deficits (60-80 percent of normal over the past three years).

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