MEA444: Mesoscale Analysis and Forecasting In-Class Lab 7 due: Monday, 2 April, 5 PM

COMET Convective Storm Matrix, available at http://meted.ucar.edu/convectn/csmatrix/

1. IN-CLASS. Form a group of 2-3 students. Run at least 25 of the sounding/hodograph combinations in the matrix. Make notes for each run on the attached “Convective Storm Matrix Answer Worksheet” and then construct the following diagrams using the attached figures:

(A) A shear/buoyancy diagram that describes whether each simulation is best characterized by ordinary cells, multiple cell systems, or supercells. For shear parameters, you may use the length of the hodograph (Us) or the BRN shear. For buoyancy, you may use CAPE or LI. For the purpose of this diagram, we will define "Ordinary Cell" simulations as those for which the initial cell grows and decays without significant new cell redevelopment, "Multiple Cell System" simulations as those for which there is significant redevelopment of ordinary cells throughout the simulation, but without supercell structures present, and "Supercell" simulations as those which include supercell structures, and may or may not also include other ordinary cells.

(B) A storm-type versus BRN diagram, noting the range of BRN values associated with primarily ordinary cells, multiple-cell systems, and supercells, as defined in A above.

(C) A shear/buoyancy diagram that indicates which simulations produce the strongest low-level mesocyclones (as determined from 0.4 km view of the matrix). If possible, also indicate which of these cases exhibit possible low-level storm occlusions. This diagram defines the environments most likely to produce supercell-type tornadoes for the present simulations.

Use the above diagrams and/or the matrix itself to help you answer the rest of the questions.

2. Describe and briefly explain the storm type versus shear and buoyancy relationships revealed by your shear/buoyancy diagram.

3. Examining the matrix views, describe the influence of variations to the buoyancy (stability) profiles on overall storm structure and evolution.

4. For a given hodograph and magnitude of vertical wind shear, what is the role of dry mid-level air on storm evolution?

5. What is the role of shear depth in controlling resulting storm structure?

6. What is the role of hodograph curvature in controlling resulting storm structure and evolution for strongly-sheared environments?

7. What values of BRN are most likely to be associated with supercell storms? Are there cases with BRNs well within the supercell range for which supercells do not occur? Explain why.

8. Can you find other significant storm structures as you further explore the matrix? Look for shallow (mini) supercells, HP supercells, and storm systems conducive to producing straight-line winds, such as bow echoes. Note which simulations display these structures.