Department of Earth & Climate Sciences Spring 2015 Meteorology 201 Name _____________________

Laboratory #11: Joplin Tornado Day --1600 UTC Surface Chart and 1200 UTC Hodograph(100 pts) -- Key

Last day to work on in class will be April 29, 2015

1. Figure 1 is the 1600 UTC surface chart on 22 May 2011. Isobars are drawn at two

millibar intervals, with two labeled. You are also provided a separate clean copy of this chart for your final analyses. (30 pts)

(a) On the copy above, draw blue, brown, and red streamlines, as we have have done in class many times to help find important boundaries; (b) On the copy above, label all the isobars NEATLY; (c) On the copy ablove, label lows and highs (if present) using the correct color convention; (d) On the copy above, note that the isobars are strongly kinked away from low pressure in certain locations. It turns out that isobars are strongly kinked

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usually in areas in which they cross boundaries. Using this knowledge, and your results in (a) above, now draw in all the boundaries, using correct symbols and color conventions. (e) Transfer all that you’ve done above to the final clean copy. This is what you will turn in and what will be graded. Neatness counts here.

2. Table 1 shows the wind directions and speeds observed in the Springfield sounding 12 UTC 22 May 2011. Figure 2 is a blank diagram called a “hodograph” . It allows us to visualize the way wind directions and speeds vary with height. (70 pts)

Table 1a: Winds and pressures observed in KSGL radiosonde launch, 12 UTC 22 May 2011

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Pressure (mb) Height (m) AGL Direction (deg) Speed (kts) 962 0 160 7 925 340 195 35 850 1071 225 35 700 2709 245 31 500 5361 235 40 479 5704 235 43 Table 1b: Wind Directions (deg) and speeds (kts) at selected pressure levels

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Figure 2: Blank hodograph paper. (a) Fill in Table 1b with the wind directions and speeds extracted from the radiosonde information in Table 1a; (2 pts each for 24 points) (b) Plot an arrow (vector) for each level given in Table 1b, as shown in class. Label each arrow near its end with the appropriate level (for example, Sfc). (2 pts each for a total of 10 pts) (c) Put a black dot at the tip of each arrow; (2 pts each for a total of 10 pts) (d) Draw (neatly) straight line segments connecting each dot. (5 pts) (e) In plain english describe how the the wind in the lowest 6 km, as visualized by the hodograph you just constructed, varied with height. (21 pts) The winds change in a clockwise sense from the surface to around the 700 mb level, and then a slight counterclockwise change and then straight. The winds also generally increasd with height except between 850 mb and 700 mb. Also, noteworthy, is that the surface wind is nearly right angles to the wind in the middle troposphere.