UBC  ATSC 201 - Meteorology of Storms

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Week 4 22 - 28 Sep 2025
Monday (D1)Finish Homework from previous week.
Be sure your name, student number, and HW# are at top of every page.
Deadline:  Submit a pdf of your homework any time or date BEFORE the start of class, 2 pm Monday Pacific Time.
Morning
Midday
2 PM Pacific Time
Class:
  1. Turn in HW electronically before class starts.
  2. Demo in class of plotting hodograph (bring your iClicker). Your next reading assignment, below, covers hodographs.
  3. Video (if time allows): "The Art of Storm Chasing".  Topic: Safety.  Disk 1, Title 2, Ch 8.
Topic: Hodographs
    Textbook Ch 14: p509-520.
Learning Goals
At the end of this section, you should be able to:
  1. Plot wind profiles on blank hodographs, and interpret plotted hodographs.
  2. Explain how wind shear enables severe thunderstorms.
  3. Determine thunderstorm movement from hodograph plots.
  4. Be safe if you chase thunderstorms.

EveningReadings:
  • S.Ch10. Sections 10.4 - 10.6.
Warm-up Questions:
Do quiz W04 D2 online on Canvas.
Topic: Horizontal Winds
    Textbook sections 10.4 - 10.6. .
Learning Goals
At the end of this section, you should be able to:
  1. List the names of the horizontal winds, and describe which forces affect them.
  2. Describe and calculate the geostrophic wind.
  3. Compare other winds to the geostrophic wind, concerning their direction, magnitudes, and where they apply.
  4. Look at weather maps to diagnose wind speeds and directions.
  5. Anticipate time and space scales for various atmospheric phenomena.

    6.
Tuesday (D2)
Morning
Midday
Evening
10 PM Pacific Time
Deadline to finish warm-up Qs.
Wed. (D3).
Morning
Midday
2 PM Pacific TimeClass:
  1. Discussion & interaction on topics from readings (bring your clicker).
  2. Case studies of real weather maps to diagnose winds.

EveningReadings:
  • S.Ch10. Sections 10.7 - 10.9
  • S.Ch11. Section 11.9 (but not subsection 11.9.4). 
Warm-up Questions:
Do quiz W04 D4 online on Canvas.
Topic: Vertical Winds, Continuity & Vorticity
   Textbook sections 10.7-10.9 and 11.9 (not 11,9,4). .
Learning Goals
At the end of this section, you should be able to:
  1. Explain why air density increases when winds blow more air molecules into a volume than out.
  2. Anticipate how winds diverge in one direction in response to convergence in other directions, such as at a thunderstorm anvil.
  3. List and calculate the different types of vorticity, and describe how they relate to each other.
  4. Apply the concept of potential vorticity conservation to determine changes in relative vorticity.
  5. Describe the forces that cause changes in vertical velocity.
Thurs. (D4)
Morning
Midday
Evening
10 PM Pacific time
Deadline to finish warm-up Qs.
Friday (D5).
Morning
Midday
2 PM Pacific Time

Class:

  1. Discussion & interaction on topics from readings (bring your clicker).
  2. Demonstrations with balloons.

Evening
End-of-Week Numerical Homework Exercises.  
(Due by start of Monday's class, unless Monday is holiday, then due Wednesday by start of class.)

Homework 4:
S.Ch10 (do all on spreadsheet):  A12g ,  A14g ,
S.Ch11 (do all on spreadsheet):  A14g ,  A17g ,  A18g ,  A19g.
S.Ch14 (do all by hand on a paper copy of the blank hodograph from page 512 of textbook, and then use your scanning app (e.g., CamScanner) to make an electronic copy to attach to your HW submission):  A18c ,  A23 ,  A28 ,  A30. 

Pre-readings on tornadoes for the next class: Ch 15, p577-589. Also section 15.4.9..

Learning Goals
At the end of this section, you should be able to:
  1. Apply topics covered earlier this week to compute number answers & infer their significance.  

Saturday(D6)
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Sunday (D7)
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Notes: The textbook for this course is Stull, 2018: "Practical Meteorology: An Algebra-based Survey of Atmospheric Science", available for free online, at  https://www.eoas.ubc.ca/books/Practical_Meteorology/ .

The reading and homework assignments use the following abbreviations to indicates various parts of this textbook:

Legend:
Ch = chapter.
A = "Apply" exercises.
p = page number.
S = Stull, 2018:  "Practical Meteorology" book (online).
s = "Synthesize" exercises.
E = "Evaluate & Analyze" exercises.