Upper Air Analyses. Assignment 7. Due March 3
Purpose: (1) to analyze upper air charts during a major winter storm; (2) examine the
structure of a major winter storm on synoptic time and spatial scales.
Review the information on manual analyses of upper air charts in the Djuric text.
Charts at 700 mb, 500 mb, and 300 mb will be analyzed for the following times:
- 00z 20 March 00
- 12z 20 March 00
- 00z 21 March 00
Review the synoptic situation at each time by using the gifs in ~jhorel/met3510
Required Equipment: #2 pencil; red pencil; eraser.
Manual analyses of height and temperature on constant pressure surfaces require:
- knowledge of the typical errors likely in upper air observations
- application of the dyamical principles of synoptic meteorology (e.g., geostrophic and gradient wind balance, thermal wind relationship)
- use of conceptual models of the structure of synoptic weather systems
- compliance with the traditions of synoptic manual analyses (e.g., contour intervals, color, and labeling conventions)
Analyses will be evaluated in terms of neatness and on how well the aforementioned factors are applied.
1. For 0000 UTC 20 March:
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a. Contour in regular pencil, geopotential height at 500 mb in 60 m intervals beginning at 5520 m.
Use the plotting conventions discussed in class. Underline suspect observations that do not conform to your analysis.
Label ridge and trough axes.
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b. Contour in red pencil, temperature at 500 mb in 5C intervals beginning at -15C.
Label temperature maxima and minima.
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c.-d. Repeat a-b for 700 mb beginning at 3000 m and -5C respectively
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e-f. Repeat a-b for 300 mb beginning at 9000 m and -40C respectively
2. Repeat for 1200 UTC 20 March
3. Repeat for 0000 UTC 21 March
4. Based on your analyses, discuss the vertical structure of the weather features across the United States.
- how did the trough and ridge axes tilt with height?
- how did the baroclinic zones tilt with height?
5. Based on your analyses, discuss the temporal and spatial evolution of the weather features across the United States.
- estimate the speed and direction of movement of the major weather features
- how did the amplitude and orientation of the major weather features change with time