1. Mid-latitude wave cyclones form as warm and cold air masses interact. They typically move from west to east, with characteristics like warm fronts, cold fronts, and occluded fronts. The warm sector behind a warm front experiences warm, clear weather. 2. Hurricanes and tornadoes are both intense storm systems, but hurricanes form over warm ocean waters and can extend over 300 miles while tornadoes are relatively small, land-based storms. Both pose severe dangers like high winds and storm surge. 3. Climate classification systems like Koppen identify different climate zones based on factors such as temperature and precipitation patterns. For example, Am is tropical rainy, BW is dry and subtropical, ET

1. Weather systems
• Product of air mass characteristics
• - and upper air influence
• jetstream ( polar, - especially polar)
• Violent weather: tornado, hurricanes
• /

2. Mid latitude wave cyclone
• 1. Most common system in our region
• 2. Here storms move from west to east
• 3. Pattern looks like an ocean wave
• 4. Components:
• warm front, cold front, open
system. Ends with an occluded front

3. MID LATITUDE WAVE CYCLONE

4. STORM SYSTEMS

5. Ferrel & Ballots Law
• Ferrel discovered the pattern of windflow
associated with pressure gradients.
• Buys Ballot clarified this with an example –
“Sailors Law” In the Northern Hemisphere
if you stand with your back to the wind
where two pressure systems abut – then
the low pressure is on the left hand side.

6. Ballot’s Law

7. thunderstorm

8. microbursts
• 1 mile in extent
• Winds up to 150-200 miles per hour
• Hazard to aviation
• Caused by sudden evaporation of fallen
precipitation ( or sudden contact with cold
air) – cools the air and gives it a burst of
speed ( down and divergent flow)

9. Microburst ( opposite of a tornado)

10. Photo - microburst

11. Hurricanes
• Where: Develop over oceans 5-30
degrees from equator.
• Stages: Easterly flow ( convergence)
• Trop. Disturbance: unorganized
• Trop. Depression
organize( 39mph winds)
• Hurricane 75+ mph winds

12. Hurricane facts
• Called cyclone in India/Australia,
• N. & S. Pacific typhoon
• Philippines Baguio
• Same type of storm
• - Seasons. Atlantic May-Nov.
• S. Hemis. Nov- May

13. Areas of impact

14. Descriptions
• Extremely low pressure ( record 870 mb)
• usually ~950 mb.
• Effective energy conversion- takes water from
ocean surface, evaporates it rapidly –
• latent energy released when forced upwards
and condenses ( think vacuum cleaner)
• Anatomy: eye, eyewall, bands of outer clouds –
creates a storm surge. can last for weeks,
extend over 300 miles

15. Hurricane Floyd - 1999

16. Hurricane Scales
• Saffir-Simpson
• 1 75-95 mph
• 2 96-110
• 3 111-130
• 4 130-155
• 5 155+

17. Tornado
• Land based storm
• Lowest air pressure on record
• Average speed of winds ( 100 mph)
• Size from a few feet to a mile or more
• Occur where warm and cold air meet
• Last only a few seconds to a few minutes
• Devastating impacts

19. Fujita-Pearson Scale
• Based on 3 second bursts as measured
by damage to categories of structures &
natural features
• Began use in February 2007
• EF 0 – winds 65-85
• 1 86-110 4- 166-200
• 2 111-135 5- 200+
• 3 136-165

20. Seasonal Tornado activity
• 1. Southern tier ( tornado alley) late winter
and early spring
• 2. Midwest & plains - spring to summer
• ( heat/cold & migrating jet stream)3.
Tornadoes can happen anywhere at any
time ( within the limits of colliding air
masses) and have been expanding
incidence worldwide in the past decade
•

21. Tornado families

22. F3 tornado, Moore, Ok. 1999

23. Topeka, Ka. 1966 – F5
TORNADO DAMAGE

24. North American air masses

25. Weather, prediction
• Maps NOAA
http://www.nws.noaa.gov/outlook_tab.php
• Methods: Consistency, seasonality,
averages, sensors & modeling

26. Climate
• It’s as easy as abc(de)
• Koppen classification
• based on suitability for agriculture
( moisture( seasonal) & temperature)- the
best proxy for climate is
latitude/continentality
• A= tropical-& rainy ( over 64degreesF)
• B- dry no permanent surface streams

27. Climate cont.
• C. Mild, humid ( summer & winter
seasons) –coldest mo under 60 deg, but
above 26 degrees,
• Summer over 50 degrees
• D. Cold snowy forest ( microthermal)
• summer above 50, winter below 26
degrees
• E. Polar- avg temp in summer below 50
degrees

28. Climate (3)
• H- highland cooler than surrounding
flatlands
• - 3 letter classifications
• 1st
letter based on temperature
• 2nd
letter is season of dryness( or moisture
related)
• 3rd
letter more detailed temperature

29. Climate influences/ Regions
• 1. Latitude – most influence
• 2. Continentality – coastal/inland
influences
• 3. Elevation
• 4. temperature ( also influences moisture)
• 5. cycles ( seasons)
• temperature zones
• Precipitation zones ( isohyets)

30. Koppen map
• http://www.uwmc.uwc.edu/geography/100/
koppen_web/koppen_map.htm

31. Precipitation patterns
• Wet equatorial
• Trade winds) 25-30 N/S east coast wet, warm (
E. Brazil
• Dry west coasts( you are here
• Midlatitude deserts & steppes ( inland & rain
shadow) Mojave
• Moist subtropical ( 25-45 degrees N/S Miami
• Midlatitude west coasts ( 35-65 n/s) westerly
winds & wet
San Francisco

32. Climate regions- A

33. Climate region B- Kelso Dunes

34. Climate C

35. Climate d- Boreal forest

36. Climate ET

37. EF - arctic harp seal

38. Climate relevance
• 1. Physical setting for all plant, animal
and human behavior – limits of living
things are largely related to temperature -
• 2. Relatively unchanging for millions of
years – but changes with cycles of Earth’s
location and orientation ( orbital and axia
• l shifts)
• 3 Range of temperatures for humans

39. Human narrow comfort zone
• Homeothermic
• Maintains core temperature
above average environment
temp.
• Normal 37 C (98.6)
• Lower limit- hypothermia
• drop of 1.8 – 3.6F from normal
• Heat: hyperthermic Above 38C
fever, 40C critical, 44C
(100% death rate) or
• F: >104F starts, over 106F
brain death begins, over 122F
certain death

40. Weather quiz
• 1. Diagram a mid-latitude wave cyclone.
• - label the parts
• - Describe the process of origination
• - Which part has warm, clear weather?
Why?
• - Which part has violent weather?
Why?

41. quiz
• 2. How do hurricanes and tornadoes
differ?
• - Describe the dangers associated with
hurricanes.
• What areas of the U.S. are at most risk
from hurricanes? From Tornadoes?
• 3. In the Koppen system – identify the
characteristics ( and example of a
location) for: Am, BW, ET, Csa climate
types

42. Quiz (3)
• 4. How are desert plant and animal
species ( and the soil) specially adapted to
the lack of moisture?
• 5. What danger does a microburst pose
to aircraft?