1. Dynamical Effects of Storm Generated Mesoscale Processes and Pressure perturbations
Terrance Seddon

2. Over view Dynamical effects Generation of Mesoscale Pressure fields
Evolution of supercells to the tornadic phase
Cold pool interactions
Pressure perturbation

3. Generation of Mesoscale Pressure fields
Dynamic effects of lifting, such as lifting pressure gradients on the flanks of updrafts, contribute to the splitting of storms
Dynamic lowering of midlevel pressures induces updraft growth on both signs of the updraft,
P’NL=-ζ2

4. Illustration for signs on updraft

5. Illustration for non-linear hodographs

6. Evolution of storms into Tornadic phase
This evolution is not completely understood, but some things are known about what is needed to cause it.
They must injest streamwise vorticity into updrafts
Baroclinic vorticities must generate along forward-flank downdrafts
Mesoscale Vortex breakdown
The final ingredient can also happen to the tornado vorticity itself, resulting in smaller scale suction vorticities

7. Cold pool interactions
Cold pools are responsible for new convective development.
With a proper balance between cold pools and low level shear, continual regeneration of storms is possible, but not required for long lived storms.
This balance is usually complicated by other sources of vorcitiy

8. Cold pool and wind shear interactions
Top pictures show a zero shear environment, with wind speeds the same all the way up
Lower pictures show an environment where the wind speeds are faster near the surface and decrease as they go up.

9. Proposed events leading to Mesoscale influences
Steps
Referenced figures
Initial updraft leans down shear due to ambient shear (a)
Cold pool develops and counteracts the down shear tilt. (b)
Cold pool overwhelms the updraft and creates a rear-inflow jet. (c)

10. Divergence of the horizontal momentum equation

11. Questions??