NOVEMBER 13 , 2013

Lab 9

Meteograms

A time display of weather information for a single observing site

• Temperature 21Z? __

• Dew Point 6Z? __• Wind Direction 8Z?

__• Pressure 03Z? __

23°F6°F

W1032mb

Laboratory Exercise 14.10 a & b (20 POINTS!)

Researching the frequency of large hail (>2” diameter) in each U.S. State

http://www.ems.psu.edu/~nese/hail.htmUse Figure 15.40b for Part b.Part a.

Maine: ___ occurrencesPart b.

Area of Maine: _____ 10,000 mi2

Normalized Hail Occurrences = = 2.3 occurrences per 10,000 mi2

8

3.5 (Using Figure 15.40b)

Map of U.S.

Tornadoes – Suction Vortices

Some of the most violent tornadoes contain smaller whirls that orbit around the center of the parent tornado, guided by the parent’s counterclockwise spin - Multi-Vortex Tornadoes.

Suction Vortices – smaller, whirling offspring within a larger tornado

Cycloid – looping damage path caused by a suction vortex

Tornadoes – Suction Vortices

Source: wxbrad

Tornadoes – Suction Vortices

Calculating maximum wind speed of multi-vortex tornado Rotational winds = 90 mph Moving North at 10 mph Suction Vortex wind speed = 35 mph

Maximum wind speed = (90 + 10 + 35) mph = 135 mph

Enhanced Fujita Scale

Source: weather.com

Determining Wind Speed of Tornadoes

Photogrammetry – frame-by-frame analyses of flying debris in a tornado yield the distances objects move over a specific period of time

Wind speeds can be calculated from these distances and time

Velocity = 23 mph

Object Weight (lbs) Exposed Surface Area (ft2)

¾-inch sheet of plywood

90 32

Lab 9 Assignment

13.10 a, b, c14.3 a, b14.10 a, b (use fig. 15.40b for part b) (20 points!)15.1 a, d (see p. 662)15.5 a, b, c15.6

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Ask Paul or Matt if unsure of theirs!