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Mesoscale Meteorology
Chapter 1 - Markowski & Richardson
1) What are the spatial and temporal scales of motion? (See Orlanski, 1975)
2) A synoptic disturbance is baroclinically unstable.
a) Define baroclinity.
b) Define baroclinic instability.
3) Define thermal wind.
4) What is meant by an order of magnitude?
5) Mesoscale events are non-hydrostatic
a) Define hydrostatic
b) What is meant by H/L ~ 1? Discuss what is meant by the scaling of equations.
c) Weight of the air above you not the sole contributor to pressure. What else is?
6) Know the difference between geostrophic and ageostrophic motions.
7) Rossby Number (1.1) is a good delineator between synoptic and mesoscale systems.
It scales to V/fL where V is the magnitude of the velocity, f is the Coriolis parameter
and L is the length scale. Foundationally, it is a ratio of the acceleration of the
horizontal wind to the strength of the Coriolis force.
a) What is the Rossby number for synoptic and mesoscale motions?
8) Compare the Coriolis force to the pressure gradient force in synoptic and mesoscale
events.
a) The Coriolis force depends on time and thus as mesoscale events approach the
meso-alpha range, it becomes more and more important.
Chapter 6 - Markowski & Richardson
1) What is meant by evaluating the difference in the Rossby number with respect to
events along the front and across the front?
2) Section 6.2 omitted. However, remember what virtual temperature and θV.
3) Outflow Boundaries
a) Why is high pressure associated with the cold pool.
b) What is meant by mesohighs or “bubble highs?”
c) Why is the θE smaller within the cold pool? Does θE change when rain falls
through a subsaturated parcel?
4) Along gust fronts, large regions of high vertical vorticity break off into discrete
patches. What might this lead to?
5) 6.3.3. Do you think that a gustnado is a tornado?*
*
From a personal correspondence with Paul Markowski – “I agree that we should not be issuing tornado warnings for gustnadoes, but
the AMS Glossary defines a gustnado as a ‘short-lived, shallow, generally weak tornado.’ Moreover, it defines a tornado as a
‘violently rotating column of air, in contact with the ground, either pendant from a cumuliform cloud or underneath a cumuliform
cloud, and often (but not always) visible as a funnel cloud.’ The ‘underneath a cumuliform cloud’ permits gustnadoes to be tornadoes.
By this definition, dust devils also are tornadoes if they're beneath a cumulus cloud. I think the definition should be changed.”
6) Drylines
a) What are the air masses on either side of the dry line?
b) What helps create a tighter dry line?
c) Keep in mind that a dryline may or may not be associated with a pressure trough.
d) What is the result of mixing behind a dry line?
7) What is the source of a capping inversion associated with a dry line? How does the
presence of CIN improve the chances for severe convection?
8) Differential heating boundaries may result in vertical motion resulting from
solenoidal circulations. What are examples of these?
Severe Convective Storms
Chapter 1 – Doswell
1) What is the Brunt-Vaisala frequency?
2) Describe the differences in understanding a thunderstorm as a series of bubbles
vs. a plume.
3) Doswell maintains that the idea of cold air choking off the updraft is incorrect.
Discuss.
4) What are the types of thunderstorms? This is largely review so I think you should
know this.
Severe Convective Storms
Chapter 2 – Doswell & Bosart
1) Quasi geostrophic theory is highly dependent upon two equations. Qualitatively,
vertical motion is a result of what two things?
2) Draw and describe a jet streak. How do the ageostrophic motions that are
generated lead to important weather events?
3) The PBL is an extremely complex layer that is dominated by latent and sensible
heat fluxes.
a. Describe some of these fluxes.
b. Define Ekman pumping.
4) The cap may result in warm moist air underrunning the stable air aloft. How could
this help develop a higher chance for thunderstorms?
5) A half-pendulum day is affected by latitude since it is related to the coriolis
parameter, f.
a. This may give rise to the NBLWM. What is this?
b. How is this different from the more traditionally-defined LLNJ?
6) How do synoptic scale vertical motions differ from mesoscale vertical motions?
How does this affect thunderstorm development?
Severe Convective Storms
Chapter 3 – Johnson & Mapes
1) Review Tables 3.1, 3.2 and 3.3.
2) According to the authors, how does dry air influence the severity of storms?
3) The Bulk Richardson Number is a way of comparing CAPE to shear. What is the
way of measuring the shear?
4) Discuss the differences between the morning and evening profiles when expecting
dry microbursts over the high plains.
5) Advection
a. Moisture advection is a significant player in destabilization. We coupled
that with moisture divergence. Discuss how these two things are
determined.
b. How does differential advection result in favorable storm environments?