NAME ___________________________________________________________________

Meteorology 535/835

 

Homework 3: Due at Beginning of Class, September 23, 2011). (Students Reviewing These Papers Are Released from this Homework)

 

 

 

 

1.  Modern concepts of deep moist convection can be traced with a field project headed by Horace Byers. What was the name of that project and in what year was the research findings from it published? (Denise Balukas is released from this question).

 

  The field project was called "The Thunderstorm Project" and the reserach findings were published in 1949.

 

 

2.  What is the minimum combined cloud shied area for a group of thunderstorms to be labeled a Mesoscale Convective Complex? (Denise Balukas is released from this question).

 

  The minimum cloud shield area criterion for a Mesoscale Convective Complex is 100,000 km^2.

 

3.  During the period 1980-1999, the maximum in the geographic pattern of giant hail reports (> 2" diameter) was centered in which states? (Victor Frank is released from this question).

 

 The maximium in giant hail reports was centered in southwestern Oklahoma and the northwest portion of central Texas.

 

 

4. The superposition of which two factors accounts for the geographic maximum in CAPE that explains the hail maximum. (Victor Frank is released from this question).

The superposition of high lapse rate air (aka "elevated mixed layer") over a poleward moving stream of moist air (aka "deep moist layer") occurs east of wave cyclone centers as they exit the southern Rockies in Spring. This occurs largely over the southern Great Plains and creates the explosive CAPE and extreme vertical velocities necessary for large hail formation.

 

5. What are the orders of magnitude of the synoptic-scale vertical wind and the convective scale vertical wind? (Jaqueline Bennett is released from this question).

The synoptic-scale vertical wind ranges from 1-10 cm s^-1 whereas the convective scale vertical velocities are on the order of 10 m s^-1. Thus, there is a 100-1000 difference in orders of magnitude.

 

6. Surface southeasterly flow underneath a polar jet is a common stratification for Great Plains' convective outbreaks. Why is such a stratification NOT conducive to severe weather development in the western Mediterranean? (Jaqueline Bennett is released from this question).

Such a stratification creates a stratification of potentially warmer drier air aloft, as it does in the Great Plains, but that air would overlie dry air in the southerlies moving northward into wave cyclones. This low level air in such a stratification would have as a source area the Sahara desert. Thus one of the ingredients for DMC would be missing: a deep moist air mass at the surface.