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Multiple Tornadic Supercells on Wednesday

10:53 am in Extreme Weather, Storm Summaries by Ted Keller

Hail near Brighton

A pre-Thanksgiving outbreak of supercell thunderstorms occurred on Wednesday the 24th in the Ozarks.  Some produced tornadoes.

It would be a challenge for me to count them from memory!  I know that several passed over the same corridor affecting portions of Vernon, Cedar, St Clair, Hickory, Polk, Dallas and Camden counties.  This was the earlier portion of the outbreak from mid afternoon through early evening. 

Damage was reported near Wheatland and Cross Timbers in Hickory County from this early round.  This was confirmed as two tornadoes today by the National Weather Service. 

Later in the evening, the supercells started shifting more to the south.  One cell starting ramping up significantly as it crossed into northwestern Greene county.  This storm continued east-northeast into southern and southeastern Polk.  This storm was responsible for multiple reports of damage near Brighton on the Greene/Polk county line. This too was confirmed as an EF1 tornado by the National Weather Service today.

Looking North from Hermitage. Photo by Ron Gamble.

A supercell started showing signs of rotation in Jasper and Newton county shortly before 8 pm.  This storm remained tornado-warned as it traveled into Lawrence county.  This was of course a concern for Greene county as it approached.  As it crossed the county and city of Springfield, multiple reports of hail from quarter to as high as ping-pong ball sized were reported.  There was also some minor wind damage.  The tornado warning picked up again as it was just leaving Greene and continued through Webster and Wright counties!

Dent county went tornado-warned for a time late in the evening followed by the final warning in Barry county just before 11 pm and into the 11 o’clock hour.

The National Weather Service has a full report on this storm.

Pre-Holiday Storm Threat

5:59 am in Forecast Discussion, Severe Storms, The Ozarks by Ted Keller

Dew Points at 5 am

Here’s the latest on the severe weather expected over the area later today.

A large storm at the jet stream level is progressing into the area today.  Upper level winds have increased and the surface winds are quite strong too.  This is a strong wind shear environment and is supportive of severe storms in the Ozarks.

As is typical in “cool season” set-ups like this, the amount of unstable air is in question.  But experience has shown that as long as the proportions of shear and instability are correct, severe storms can flurish.

At this point, it looks like storms will slowly develop over the Ozarks starting around 4 pm. Those with the greatest potential be become severe early on should be in the vicinity of the MO/KS/AR/OK borders where instability will be maximized.  This is also the area where the storms will start out isolated (discrete, non-linear)

Eventually, the storms will begin to form lines and progress eastward over the Ozarks.  With such strong winds near the surface, an isolated tornado threat is real with any supercell storms.

Tornado Probability Within a 25 mi Circle

Everyone should monitor the weather carefully today as small-scale changes in the timing of features and the development of pockets of unstable air could alter the intensity of these storms.

The strong cold front that everyone is aware of will begin to speed up this evening and slide through the Ozarks after the midnight hour.  I will have a separate post regarding this front and what it will do to our Thanksgiving Day weather!

The Lebanon, MO Tornado November 10th, 1995

9:14 pm in Severe Storms, Storm Summaries, The Ozarks by Ted Keller

Storm-Relative Velocity Showing the Couplet Near Lebanon at About 5 pm

This was an interesting storm for several reasons. 

First, it was a November tornado.  Actually, we shouldn’t be that surprised at this because the Ozarks have always had a significant “second season” of tornadoes which peaks in November and December, especially when it comes to outbreaks of tornadoes. 

November, and all of the months of winter too, are considered to be the “cool season” with regard to tornado development.  Most people don’t think of this period as being a particularly threatening time for tornadoes.  But the fact is that when tornado conditions develop during the cool season, the tornado threat is just as real as anything in the heart of May!

Cool season tornadoes are dangerous for reasons beyond just public apathy.  Because the length of daylight is very short, it is likely that cool season tornadoes will be nocturnal. (occurring at night)  Now, they may simply be late afternoon or evening storms which are nocturnal because of the time of year.  Or they may be storms which develop after the late news or worse after the majority of people of gone to bed.  Such overnight storms are often aided by the natural strong jet stream patterns found during the cool season which can force tornadic conditions anytime , not necessarily favoring the peak heating of late afternoon and evening.  This tornado touched down before sunset.

In the writing of this report, I requested the radar data archive for this date.  It showed a broken line of storms, many of which were taking on supercell characteristics.   I recorded a loop of these storms in the 5 o’clock hour.  The green triangle is a “scit” where the computer has tagged tight rotation in a storm.  It lasts for two frames or about eight minutes as it zips across south Lebanon.  This tornado tore apart Tracker Marine in Lebanon, throwing boats everywhere.  It crossed I-44 and did other damage to homes.

What I really find quite interesting in this post analysis of the event is the intensity of a storm immediately to the southwest of the Lebanon storm, also shown in the radar loop.  This storm had a more persistent and stronger rotation couplet associated with it reaching a peak near Twin Bridges south of Lebanon at around 5:24 pm!  Yet there were no tornado reports with this storm.  A curiosity.

One last note: this tornado occurred ahead of a powerful cold front!  I distinctly remember working this night and while trying to stay ahead of  the tornado warnings, I glanced over into eastern Kansas and saw what sure looked like a signature of snow on radar there!  In fact, it was snow and the area received a light accumulation of snow later that night and early in the morning!

Tornadic Supercell Near Richmond, VA!

3:42 pm in Extreme Weather, Severe Storms by Ted Keller


Tornadic supercell with a hook echo passes over the northern Richmond, VA area. Tornado report at Mechanicsville, VA.

Tornadic Week

6:13 pm in Extreme Weather, Storm Summaries by Ted Keller

We’ve had a lot of noteworthy tornadoes last week in the U.S.

On Wednesday, September 15th, severe storms sprang up violently over portions of southcentral and southeastern Kansas.  Discrete supercell storms produced both tornadoes and extremely large hail. In fact, a new state record for large hail may be threatened in Kanasa as a result of these storms.  The Wichita NWS has an excellent summary of the severe weather outbreak.

Later that same evening, the individual cells merged into a severe squall line with bowing line segments as it finished moving through eastern Kansas and then headed into the Ozarks.  Shortlly before 11 pm, a weak EF0 tornado was on the ground for only one half mile about 4-5 southwest of Nixa.  The Springfield NWS has a review of the tornado as well as downbursts and heavy rain in southwest Missouri on this day.

On Thursday, September 16th, a cool front was responsible for two additional tornadic areas.  In New York City, the National Weather Service confrms two tornadoes within the city limits.  An EF0 tornado touched down in Brooklyn while an EF1 rating was attatched to a Flushing/Bayside twister in Queens.  The storm killed one person.  A link to the news story and to the NWS report.

Also on Thursday, severe thunderstorms formed in southeastern Ohio and traveled southeast into West Virginia, producing tornadoes including two EF3’s and several EF2’s.

EF0 Tornado/Wind Damage Wednesday Evening

8:24 pm in Extreme Weather, Storm Summaries by Ted Keller

The Springfield National Weather Service performed damage surveys today and determined an EF0 tornado touched down southwest of Nixa Wednesday evening.  Here is the storm report.

Additionally, a mircroburst produced wind damage west of Turners.  Several other microbursts were reported in Rogersville and near Fordland.

I have radar data processing and will update this story tomorrow.

Event summary page from the Springfield National Weather Service.

EF SCALE
EF Rating 3 Second Gust (mph)
0 65-85
1 86-110
2 111-135
3 136-165
4 166-200
5 Over 200
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