An intense low pressure system will be developing and moving from Kansas into western Missouri tonight. A few thunderstorms will be developing this evening and the issue is how many might be severe.
Overall, scattered storms will transition quickly to a line of storms later this evening across most of the Ozarks. Wind shear is very favorable for stronger storms capable of supporting strong surface wind gusts with the heavier storms. This set-up might support an isolated tornado.
Tornado Watch Likely
One overall negative factor is the low instability. Having stated this, the highest instability will set up later this evening in northwest Arkansas, extreme southern Missouri and then north central Arkansas. Low level instability with a very high humidity surface air mass will likely make the most of any long-lived updraft in a storm.
The SPC outlooks looks reasonable with regard to severe weather.
I’ll be watching this area carefully tonight. Remember, wind chills in the teens and snow flurries flying in about 12 hours! That’s why I love the weather!
Hurricane Isaac came a shore in Louisiana earlier today bringing with it lots of rain and flooding, wind gusts over 100 mph and evacuations due to high water in Plaquemines Parish. The storm has weakened a little this afternoon now at tropical storm status. It is moving slow and still causing lots of problems.
Now that the question of landfall for this storm has been answered, the next relevant question for the Ozarks is: where will this system track over the next few days?
If you have been tracking this storm, you know that it continues to track west of every official prediction made for the past several days. Where it tracks is vital to the Ozarks for two reasons: 1) it determines where the heaviest rain will be laid down and 2) it defines where a weak tornado threat might exist.
Whatever the exact track, this storm will eventually take on the look of a low pressure system tracking through the central U.S. It will have plenty of humidity tracking with it and therefore will produce heavier than normal rain near its path.
Like any low pressure area, folks in the “warm sector”, so to speak, or to the east of the low center would be subject to the best combination of unstable air and wind shear. This is in part why many land-falling tropical systems produce occasional weak tornadoes. This area is also where the heavier rain totals end up.
The rain potential is great. Some areas will likely pick up 4-5 inches, perhaps more locally!
Latest Rain Projection for Isaac, Track Dependent!
As of now, the low is projected right over the Ozarks starting late Thursday and then leaving on Saturday.
It was one year ago today, on a Sunday, that an insidious tornado tore through the southern portion of Joplin, Missouri.
Insidious because of how quickly it formed, where it formed, how intense it became and where it traveled.
Even with all of the technology at our disposal, 158 people lost their lives (NWS statistics). Here is a list of the highest single tornado death tolls on record.
Back in the 1950′s, a tornado killed 116 people in Flint, Michigan. During and soon after this tornado, huge advancements were made in tornado awareness, radar technology, storm forecasting (the “watch box” was introduced to the public) and emergency response. It has been stated that Flint was the last 100+ person death-toll from a single tornado due in large part to all of these advances and others such as warnings, weather radio and Doppler radar. While this is no doubt true, no one should believe that we reached a plateau or that this type of disaster could not happen again.
In fact, just as you would adjust what the dollar is worth because of inflation, this Joplin death toll needs a similar adjustment. Note on the list I linked above that all of the deadly tornadoes higher than Joplin happened before there was radar (Doppler or otherwise), tornado warnings, tornado watches, television, cell phones and certainly the internet. When considered in this light, the tragedy of Joplin glares even brighter.
High death tolls are a matter of horrible circumstances coming together. The real truth is that this can happen again and it will, somewhere. Population areas continue to expand. There are some who think even higher fatalities are possible.
Before I go any further, I would recommend reading the National Weather Service “Service Assessment Report” for the Joplin tornado (PDF file). A panel of individuals performed an assessment (as they do for most major tornadoes and/or outbreaks) of the events leading up to the this tornado. There are some valuable insights in this paper.
I’m an old school guy with regard to tornado warnings. Even with my all of my experience with tornadoes in the Ozarks and my inside knowledge of radar signatures, our family still takes shelter, without question, when a tornado warning is issued. I’m a strong believer that a tornado warning is not “soft”, rather, it offers a choice to take shelter, yes or no. A personal decision.
But many people don’t take shelter, at least not right away. The reasons vary but it mostly stems from a rather inescapable truth about tornado warnings: many times, nothing happens to you personally after the warning expires, even if a tornado is reported in the warned area. I state this not as a slam of the warning process but as more of a reality check of the current knowledge and dissemination limitations of the warning system.
The assessment report hits on this when it states that many folks sought a “second opinion” before deciding whether the tornado warning was important enough or close enough to take action. It is human nature to want to know what is going on around you.
Everyone needs to know that we in this country are fortunate enough to have a government organization, the National Weather Service (NWS), whose mission it is to save lives and to watch 24/7 for threatening, destructive or deadly weather situations. This is a free service paid for by your tax dollars. The warning system is a good one. Not perfect but good. It is easy to loose site of the fact that the people in the hot seat issuing warnings have a tough job. They are being asked for more and more precision even when the current technology, understanding of the meteorological process, small scale sampling of the atmosphere and dissemination paths are not up to full potential.
The question I would throw out is this: are far can we take the precision of the tornado warning process? There is an old observation, made to drive home the idea of not ignoring tornado warnings, which states “no one is going to come and ring your doorbell and tell you a tornado is coming!” Well, I don’t know about doorbells but technology might help in the not-too-distant future.
The NWS is slowing rolling out a warning system in corporation with the cell phone industry which will give you a short text warning based on you GPS position. The only issue I might have with this is when cell towers go down or become overloaded during large tornadoes like Joplin.
On the other hand, weather radio is essential to anyone who takes storm safety seriously. The reason: it broadcasts a signal on a VHF frequency 24/7 and has the ability to alert you by county and to wake you up if weather threatens while you sleep. My only wish would be to make them GPS-aware in the future which would improve the accuracy and make them truly portable. It’s one device which should definitely remain a uni-tasker, designed only to do one thing!
Coming back to the Joplin tornado, the amount of time it took for this tornado to become a monster was very, very small. The tornado was low to the ground, perhaps indistinguishable to the untrained eye from a low cloud near the ground and made worse if trees and building blocked the view of the horizon. It started on the edge of very densely populated city (couldn’t see it coming for miles and minutes beforehand). It was really the second storm to threaten the Joplin area that evening (read the assessment report) which may have caused some confusion.
This video shows the beginning of the Joplin tornado and sums up how quickly it spun into existence:
Brief update here. I’ll be chasing for KOLR/KOZL in the Mobile Weather Lab today along with Meterologist Chris Smith and Richard Hahn.
Reference tornado watch about to be hoisted for a portion of Kansas.
We will leave around noon today in search of dry line supercells. Note that we may not chase the best storm since I am somewhat tethered by any storms which could eventually roll into southwest Missouri. We’ll likely stay on the southern end of development. Even with this restriction, I have a feeling we’ll see a good storm!
We’ll be reporting in the local early newscasts and then be prepared to ride a storm or two into western Missouri before dark .
I will be intercepting these storms in Kansas and then positioning the Mobile Weather Lab to ride any threatening storms into Missouri until dark. Meteorologist Chris Smith will be along helping to track the storms! We will be doing live reports in the early newscasts for KOLR.
A threat for severe storms exists today especially for areas of western Missouri this evening. The Storm Prediction Center has put much of central and eastern Kansas and a portion of western Missouri under a moderate risk. Note that this is an evening event, no severe weather is expected during the day in the Ozarks.
A warm front will be moving back northeast across Missouri and Kansas today. South and west of this front through a portion of Kansas, the air is expected to become very unstable. Also, a dry line will be moving into this unstable air over central and eastern Kansas by later in the afternoon and early evening.
Severe storms are expected in two areas. One near the warm front may evolve earlier in the day with Kansas being the most likely location for a severe storms. These would tend to move up toward the Kansas City area. They are not the main threat.
The dry line is the second area and the greatest threat. It looks now as if storms firing along the line will quickly become severe in south-central Kansas and move northeast into eastern Kansas. There is a tornado threat with these storms. They are expected to remain discrete (single) severe cells.
Sometime during the evening hours, these storms will cross into western Missouri. The biggest questions remain how far south the line will develop and how long will these storms hang on to the severe/tornado threat? Some computer models have the environment becoming hostile to storms into the late evening hours over western Missouri while others keep it going into the evening.
To err on the side of caution, I would expect a few single severe supercells to be approaching the Missouri border by the 7-8:00 pm hour. The exact timing and extent of storms will be monitored carefully later today. I believe the threat to be greater the more north along highway 71 you are located.
The threat may extend to the Springfield area or just west and north of the city by the 8:30-10:30 time frame.
Storms today will be coming out of the southwest at around 35-40 mph.
It looks like a go for a storm chase Thursday. My concerns are still the same but I think the potential outweighs the bust factor.
The overall concern is the strength of a mid-level warm, but unstable, air layer known as the elevated mixed layer. I’m also going to keep a close eye on the quality and depth of humidity return into the target area.
The Significant Tornado Parameter (STP) from the SREF (9z run) for 10 pm Thursday is shown. This is of course after dark in that portion of the Great Plains. However, the parameter is developing nicely on the 7 pm chart. There appears to be a window for tornado development in the daylight of early evening in southwest Kansas and northwest Oklahoma.
Also shown is the significant tornado ingredients map for the same 10 pm time.
I hate to be predictible but I’ll pretty much target this area for a storm intercept, subject of course to mesoanalysis in route.
The 12z model runs from this Tuesday morning are still showing a chance for severe storms on Thursday over the Great Plains but we have issues.
It’s a lead shortwave set-up coming out of the long-wave trough out west. Adequate but not great overall shear. A cap that will quicky snuff out any storms that do develop by just after sunset. Modified continental polar air trying to ride north-northwestward out ahead of the short-wave.
Things to watch, even as late as Thursday morning: true cap strength, extent of humidity return, forcing and position along the dry line.
As of this writing, a so-so opportunity. We might get away with a drive over to around Dodge City if the morning models are telling the truth. Actually, the NAM and the SREF are hinting at possibilties even more eastward. The 18Z NAM more west now.
I am contemplating a trip to Kansas on Thursday to chase severe storms.
This is based on the data coming in from the 12z Monday computer model runs. Actually, Thursday and Friday look good but personally, Thursday works out better for me despite the distance. We’re actually talking about northwest Kansas up into northeastern Colorado. I would only as far as Kansas but it should be enough.
A strong cap of warm air will take hold over much of Texas, Oklahoma and southern Kansas on Thursday. However, a curved area of unstable air will stretch from western Kansas northwest into Colorado. I would target western Kansas as it stands now.
There are some issues. First, I’m somewhat dubious of the forecast values of dew points into the sixties riding NNW into this region. Lower dew points would reduce the instability. I could handle this if the wind shear was fantastic it it too might be right on the edge.
It was the third day of an extended storm chase into the Great Plains and I have several good storms to show for it including an awesome twin tornado shot near Cherokee, Oklahoma during the last 20 minutes of the chase on Saturday.
First off, there was an incredible number of violent tornadoes in Nebraska, Kansas, Iowa and Oklahoma on Saturday. Thoughts and prayers go out to all affected.
I chase storms as a hobby and in an official capacity either for broadcast (KOLR/KOZL) or for education (Missouri State University). Chasing is thrilling to be sure but I also learn more about tornadoes and supercells every time I head out. The twin tornadoes pictured are an excellent example of how much different each tornadic storm can be.
The chase started in Kansas. We hung in east Kansas for a while on a hunch that something my fire there but abandoned this idea and started heading west in southern Kansas. Several supercells were forming southward into Oklahoma and the plan was to catch one and then drop south to the next one, which largely worked out for us.
The first encounter was south of Pratt, Kansas just southwest of the town of Sawyer, KS. Radar indicated rotation with this storm and visuals confirmed the existence of a well-defined wall cloud. The wall cloud passed just north of our position south of Sawyer. It passed north of the town as well. We chased it north of town as it was weakening. It looked is if a new circulation center had formed on radar but this was hard to get a visual on. There was a tornado report on highway 54 just east of Pratt which seems to confirm this idea.
We stopped for three more supercells before dark. One was near Medicine Lodge. Once again, a clear rotation that never tightened up into a tornado. The second storm was south into Oklahoma, it passed just northwest of Burlington on Highway 11. We watched this for a while in the 7 o’clock hour. It became clear that a larger storm to the south was hindering the development of this cell.
It should be noted that we were deprived of radar data at this point. 2G Verizon was the best we had which delivers images slowly! If I had know how much larger the southern-most storm was, we would have broken off of the Burlington storm sooner!
With only about 20 minutes of daylight left we checked out the last storm. It was on the way home anyway. When we busted out of the “anvil core” heading south on highway 11, another wall cloud was visible on our right. A family was watching this storm and said “you missed it” They were referring to a tornado which had already formed and dissipated. I advised these folks to keep following us south as we were too close to the direct path of the storm.
Second Stop, Two Circulations
In the video, you can see a second tornado formed as we were driving south. The right twister appeared white in the sunlight. We stopped again at the Highway 11/64 intersection just north of the Cherokee Airport. This is where one tornado passed in front of the other (see picture) and then became one again as it passed just northwest of this intersection. A close-up of the ground dust and debris is included in the video too.
Finally, we took up a position in the parking lot of the airport. The video shows this as a classic looking black tornado with a diffuse back-light made of of rain and hail providing excellent contrast even after sunset.
For those wondering, the Cherokee storm went on to produce the EF-3 monster tornado in southeastern Wichita later in the evening.