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VToo.2 Update #1 Sunday June 6th

1:54 pm in Uncategorized by Ted Keller

Well, we’re heading for the first target area of the trip, which will be northeastern Colorado. We are seconds from crossing into Colorado from Kansas.  I’m having an issue with our GPS device in case you’re wondering why the position isn’t working.

Some encouragement came when the SPC actually put a minimal (2%) tornado risk out with the late morning update! 

It is interesting that a NW-SE boundary of maximum dew points has set up this afternoon in northeastern Colorado.  There is also edvidence of pre-convection occuring in northern Colorado and southern Wyoming.  For these reasons plus the fact that we’ll need to be in western Nebraska for Monday’s initiation made us decide to head to Sterling, Colorado this afternoon, ETA about 4 pm MDT.

Chase Week 2010 Update. It Needs a Name!

7:59 am in Storm Chase VToo.2, Storm Chasing by Ted Keller

 I realized this morning that this chase needs a name.  So playing off of our reference to last year’s MSU chase as Vortex Too, I think I’ll call this year’s VToo.2.  Catchy? Well, maybe not but it’s shorter to type!

The morning SPC forecasts are somewhat encouraging in that they back up my late night post with regard to the overall set up early next week.  Of course, forecasters and storm chasers always take any longer range forecast with a grain of salt.  Having said that, the usual due dilagence will apply as the situation unfolds over the next couple of days.

I will be giving Annette from Artbeats a meeting point later today for the Sunday chase.  Sunday isn’t the best chase day according to conventional wisdom but I think it will hold some surprises!  Besides, the day will also be spent getting logistics worked out for the days afterward.

I’ve added to my chasing arsenal this type around.  I bought a suction-cup camera mount from Filmtools to help with live streaming.  I’ll be using my old JVC SD camera for that purpose. Also, my grateful thanks to Bart Comstock for helping be aquire high speed internet access earlier this week.

I am trying out Corel VideoStudio Pro X3 for video editing in the field.  I have been a long-time user of Pinnicle Studio 12 but it is slow and cludgy when compared to VSPX3.  I’m hoping for good things from this software!

More updates later!

VToo.2. Outlook for Chase Week

11:16 pm in Storm Chase VToo.2, Storm Chasing by Ted Keller

The 18z and 00z  model runs have been consistent in setting up a quasi-stationary zonal flow pattern across the central Plains Sunday-Tuesday.

For Sunday, our best bet would likely be along the northwest nose of a tongue of higher moisture and instability coming from the southeast into Colorado.  The placement of the western end of a cool front will have to monitored carefully.  Surface winds will be backed and deep shear sufficient for storms.  One drawback will be a strong cap in some locations or one which will strengthen quickly after dark.  I still like Lamar, CO as a starting point.

Monday and Tuesday are quite interesting.  Experience has shown that this type of pattern where a strong, nearly zonal jet stream flow is just north of unstable air suggests that storms cells will initiate in a narrow zone between a strong cap and favorable shear during the late afternoon and early evening and then become nocturnal MCS’s traveling ESE overnight.

Wednesday and Thursday have been all over the board.  Some model runs have really amplified a ridge over the western plains.  The 00Z run of the GFS tonight is quite a bit more optimistic in digging the trough coming ashore out west more to the south.  This remains a mystery and of course the handling of troughs coming off of the Pacific into the western U.S. is always a crap shoot.  We, of course, remain hopeful!

Annette from Artbeats made it to Utah last night.  We will be giving her an update on the road on Saturday.

The final preparations for streaming through Severe Studios were made today.  I spent quite some time at Radio Shack on Friday buying adaptors to make my duel-band external antenna plug into my recently-acquired Sprint USB modem card.

More updates later on!

A Wild Outbreak of Tornadoes

7:05 pm in Severe Storms, Storm Summaries by Ted Keller

No Place on Earth

can put the ingredients together for an outbreak of tornadoes quite like the central U.S. and the outbreak of May 10th, 2010 certainly reminds us of this fact.

Rope Tornado Near Yukon, OK. Photo by Chris Novy.

The outbreak came together as extremely unstable air was pulled northward ahead of a dry line.  At the same time, a very strong but compact area of intense air level winds (shortwave/jet max) moved over the area.

The alignment of the upper level winds and unstable air was going to last for only about six hours and in a relatively small area.  But in that time and space frame, numerous supercell thunderstorms quickly evolved, most into tornado-barring cells.

At this writing, the National Weather Service in Norman, Oklahoma has indentified ten areas where tornadoes likely tracked on this day.  More tornadoes occurred in Kansas and northeastern Oklahoma. This will be refined more as survey crews finish their painstaking task.  The death toll stands at five. 

NWS Reviews:

The Set Up

Low Wall Cloud, Multiple Vorticies. Photo by Allan Detrich.

It was a situation typical to the Great Plains but with the volume cranked way up.  It starts when a “trough” of low pressure develops over the western U.S.  This encourages steady southerly winds to blow over the central U.S. drawing humid air from the Gulf of Mexico northward.  On this day the dew points, a measure of moisture in the atmosphere, were quite high and this humidity helps to make the air unstable.  In fact, all else being equal, higher dew points will generally lead to more violent storms.

Unstable air is produced whenever you can warm the air at or near the surface of the earth while keeping things relatively cool aloft.  Moisture adds to the instability because when water vapor condenses back into visible cloud droplets, the energy in took to evaporate this water is released into the atmosphere.

Now on top of all of this, the jet stream winds, fueled mostly by differences in temperature from south to north, were howling!  These winds do several things.  The overall increase in wind speed with increasing height provides structure for developing thunderstorms and allows them to become “supercells”.  Also, the speed and directional changes in the wind close to the earth’s surface provide a spinning which the updrafts of a thunderstorm inherit.

Sometimes, the “wind shear” can be too strong and developing storms will get “sheared” off.  The winds on the outbreak day were strong enough to be a concern for this happening BUT the instability was so strong that the updrafts which make up a thunderstorm rose violently and were able to survive, even flourish, in this environment!

Chasing These Storms

The wind speeds were very high in the atmosphere leading to storms traveling over 60 mph!  This “storm motion” made these storms difficult to chase. Still, there were some shots.  The multiple-vortex tornado shot by Andy Gabrielson is stunning!

Some local chaser friends of mine Jason Blum, Dave Toner and Cody Hudson got themselves into a dangerous situation near Arkansas City, KS.  Their vehicle goes down a steep embankment.  Then the tornado passes nearly on top of them!

The Ozarks Missed This

Some may wonder since weather moves from west to east why the Ozarks didn’t see at least a weaker version of what happened out west, especially considering how fast the jet stream was.  The answer is that we were in much more stable air.  I watched as these storms literally fell apart while racing eastward.  The fast jet stream winds actually outpaced the ability to draw unstable air out ahead of the system.  Later on, we actually did have a tornado warning or two west and northwest of Springfield but this was mostly due to the incredible wind shear working on even the weakest updraft to see if can be coaxed into rotating.

Monday Severe Weather Threat

1:40 am in Forecast Discussion, Severe Storms by Ted Keller

High Risk on Our Doorstep Monday

The Storm Prediction Center upgraded their forecast overnight to a high risk in areas just to the west of the Ozarks with a moderate risk still forecast for the western portion of our viewing area.

A very potent upper level jet stream will interact with a rapid return of moisture near the ground to produce an explosive combination leading to the development of classic, discrete supercells which will likely bare tornadoes shortly after they fire through Oklahoma and Kansas late Monday afternoon.
There is a good chance that some of these cells will make it into the Ozarks Monday evening!  The chance for a tornado is fairly high in areas of extreme western Missouri and Arkansas beginning right around 7 pm.  It is possible for some of these storms to continue to move into the Ozarks later in the evening.
While the axis of unstable air is not forecast to shift east and be as strong as it will be in the initial storm formation area, severe weather is still a concern over all of the Ozarks Monday evening and overnight into early Tuesday!

Severe Weather Monday

10:27 am in Forecast Discussion, Severe Storms, Storm Chase Discussion, Storm Chasing by Ted Keller

Severe Outlook for Monday

This has been holding together for a few days now in the computer model forecasts so confidence is running higher that an outbreak of storms will occur over the central Great Plains Monday.

There has been some fluctuation in the position of the dry line which defines the western edge of the threat area,  If it ends up over central portions of Oklahoma and Kansas, the Ozarks would see whatever supercell thunderstorms do develop move into the area later that evening.

One computer model  (NAM) from 12z Friday has pushed the dryline back westward after trending more east the past few runs.  The GFS model is sticking with an “I-35″ (or thereabout) solution which is more east.

Since the event is still 78-84 hours away, there will likely be more adjusting of the position east or west.

The differences are arising because the speed and position of the shortwave trough are radically different between the NAM and GFS computer model!  I posted the images below.  This will make a HUGE difference in where the threat area ends up!  This position will shore up as soon as we get closer to Monday and the shortwave “comes ashore” to be sampled better by upper air measurements.

My friends Matt Gingery and Jill Gilardi will be out chasing on a special project starting Monday.  What a way to kick things off!  I wish them luck and safe travels!

I will be doing a special “Upstream” broadcast on Sunday evening, most likely after the 00z NAM comes out which will be after 9 pm sometime.  I’ll keep you posted!

NAM 500 mb 7pm MondayGFS 500mb at 7pm Monday

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