How common is it for supercells to develop into linear MCS?

[Tim Moxon]

At 2/3rds of the way through my first chasecation in the U.S. there's been one feature of the weather situations that has surprised me, even after months of fairly extensive reading on severe / summer convective weather beforehand (though I may have just missed some bits!).

We've been lucky enough to see supercellular storms on 15 out of 16 days so far. However on 14 of these 15 chases, the storms we've been on have finished the day as a linear MCS. Though I knew this could happen, I was expecting it would be an occasional occurance. Is it actually a typical end to the day that it will happen, or has it just been a specific feature of the recent weather?

Many thanks,

Tim

 

[Paul Sherman]

Tim

I would go with 90-95% of all Chase days ending in an MCS Or Lining out and these percentages would also ring true for every year I have chased since 2004. The only time's this year I can think of where it did not happen was when Diurnal Heating came into play and Storms/Supercells rapidly diminished as Daytime heating finished or when LP Storms refuse to leave the Dryline, also the absense of the LLJ (Low Level Jet) In the evening hours has a profound effect on wether an MCS Either keeps going or forms.

Have to check over my chases but would think 9 out of every 10 had an MCS

29th April - N Kansas Lined out into an MCS
01st May - Arkansas Lined out and produced incredible flooding in Tennessee
06th May - N Kansas Lined out into a Huge MCS In NE Kansas and SE Neb
10th May - High Risk in OK Then Lined out into MO & AR
11th May - Woodward LP Supercell shrunk to nothing and NO MCS Formed
12th May - W Oklahoma lined out into an MCS
14th May - NM Chase with Diurnal Storms - NO MCS Formed
16th May - S Texas Supercell with SE Moving MCS
18th May - Tx Panhandle Dumas Tornadic Storm - Overnight MCS
19th May - Wynewood and Hennessy Day - E Moving MCS
21st May - LP Supercell near Silverton - NO MCS Formed
22nd May - Bowdle (SD Storm) - MCS moved into MN/IO
23rd May - KS & CO Tornadic Storms - MCS Moving E Later
24th May - SD Wedges Again - NE Moving MCS
25th May - SE Colorado and KS Tornadoes - E Moving MCS Through Kansas
31st May - Campo Day - Smallish MCS Moved East through Guymon
01st Jun - Moderate Risk day NE - Big MCS E Moving

02nd to the 9th June also had every day with an MCS at the end of the day.

So about 90-95% is about right

Regards

Paul S

 

[Tim Moxon]

Hey Paul,

Thanks - that's really interesting stuff, and great detail, very much appreciated.

Funny that, so far as I recall, it wasn't ever really covered in things like the storm chasing handbook or other of the more high level chasing overviews. It's certainly something that needs to be incorporated into your plans for finishing the day as we often find ourselves with a reasonable distance to travel to escape them, and their motion tends to follow the upper level winds so you need to be aware, for positioning, that a new motion, and much larger scale weather, is likely to be the last obstacle of the day.

Thanks again,

Tim