Mesoscale Convective Vortexes and tornadic supercells

Jul 17, 2004
Piedmont, OK

On my way to church going down the Kilpatrick Tpk at around 1745cdt, I
noticed a developing cell that was just starting to precipitate which was
aprox. 10mi. east of the I-44 Turner Tpk./I-35 intersection. What was
interesting was that the storm exhibited a sheared look to it and was
signifigantly leaning to the northeast. There were a couple of what look
liked inflow bands on its south side. I did not notice any rotation,
although there were a few brief lowerings.

At that time, I remembered that MCV over Commanche Co. a couple hours
earlier and wondering if anything would become of it as it tracked
northeast toward the OKC metro area. As I stated in my earlier post, I
thought the lack of instability and low level shear would preclude
anything of substance, but looking at that developing CB, I wondered if I
was to leave church hearing of some suprise svr wx events. I later found
out that according to reports from other reliable sources and looking at
radar loops from the last couple of hours, small but heavy cells
exhibiting supercelluar characteristics were occuring just east of Norman
and OKC...undoubtably, the MCV must have been the culprit.

In my never ending thirst for more knowledge of our atmosphere, I thought
about posing a question to the group concerning MCV's, what's the prime
environment that they can form and just what are the chances of a storm
within its influences that can increase its chances of tornadoing?

Otherwise, I'm sure loving this cool wet pattern here in Okla., looks like we may pay
for it with excessive dewpoints well into the 70's by weeks end and temps
back into the 90's...ugh!

Bring on the fall season!
You got me on this one Rocky! Nice you guys are getting some rain up there. We were having the same thing last few weeks in Austin and it really brought the temps down and made it bareable. I'll leave the answer for some with longer hair than me but wanted to say Hi, and that David Douglas and I enjoyed chatting with you in Childress June 12th - Jayton day even if it was brief. We ended up catching some nice torns.

I read a little bit about these somewhere a while back. If I am remember correctly, you typically find precipitation in the part of the vortex where warm air is being advected (because that results in ascention of air), and one is more likely to find severe (possibly tornadic) storms where you have good instability and strong vertical shear from the vortex. I'm sure there's a lot more to it than that, but that's the watered-down version I remember reading about in some textbook (or somewhere).

As to the best environment for MCV's to form, I'm sure someone else on the board can answer that question in greater detail. I really don't know much about the dynamics of these systems. But just thinking about it, I'd reckon they'd be some sort of spinoff from within MCS's or something of that nature.
Notes from UCAR:
mesoscale convective vortex (MCV) --A low-pressure center within an MCS that pulls winds into a circling pattern, or vortex. With a core only 30 to 60 miles wide and 1 to 3 miles deep, an MCV is often overlooked in standard weather analyses. But an MCV can take on a life of its own, persisting for up to 12 hours after its parent MCS has dissipated. This orphaned MCV will sometimes then become the seed of the next thunderstorm outbreak. An MCV that moves into tropical waters, such as the Gulf of Mexico, can serve as the nucleus for a tropical storm or hurricane.

MCCs and other types of MCSs occasionally spawn an upper-level circulation called a Mesoscale Convective Vortex (MCV). Although its parent system has died, an MCV can continue moving downstream as a swirl in the atmosphere and trigger subsequent convection and MCSs.

The flow field in the later stages of an MCC is characterized by divergent anticyclonic outflow near the surface and aloft within the anvil, with convergent cyclonic flow at midlevels. Like the northern line-end vortices of squall lines discussed earlier in this module, this mid-level cyclonic flow is often referred to as an MCV (or sometimes MVC as discussed earlier). These can be generated by large MCSs, including MCCs, and are most likely to survive beyond their parent MCS when the environmental vertical wind shear is weak. These conditions are often met in the classic weak synoptic setting for derechoes under a large-scale ridge.

Mid-level cyclonic vortices, as documented by Trier and coauthors in a 2000 paper, are frequently observed to be the focus of subsequent convective outbreaks. In fact, 9 of 16 MCVs they observed in the central U.S. during the convective warm season of 1998 were responsible for initiating subsequent deep convection and heavy precipitation. Thus, MCVs spawned by some MCSs are a significant indicator of the location of possible future convection initiation.
The project BAMEX, did research on bow echoes and MCV's

Links are so long. did not work, I suggest copy and paste the links in your browser.

Some literature, not a complete list. Ony the abstract links are given
Midlevel Cyclonic Vortices Generated by Mesoseale Convective Systems
Diana L. Bartels and Robert A. Maddox
Monthly Weather Review: Vol. 119, No. 1, pp. 104–118.

Circulations Associated with a Mature-to-Decaying Midlatitude MesoscaleConvective System. Part II: Upper-Level Features
Richard H. Johnson and Diana L. Bartles
Monthly Weather Review: Vol. 120, No. 7, pp. 1301–1321.

The Kinematics of a Midlatitude, Continental Mesoscale ConvectiveSystem and Its Mesoscale Vortex
Jason C. Knievel and Richard H. Johnson
Monthly Weather Review: Vol. 130, No. 7, pp. 1749–1770.

Add some more, when I find another WIFI spot.
Searching for a city and apartment still.

Mike (EF from Chat)