New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Severe and Unusual Weather Week 3 Notes

by: Rhiannon Cobb

Severe and Unusual Weather Week 3 Notes METR 140

Marketplace > University of Nebraska Lincoln > Science > METR 140 > Severe and Unusual Weather Week 3 Notes
Rhiannon Cobb
GPA 4.0

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

These notes cover A LOT. Covers both Tuesday and Thursday notes over hurricanes and air pressure/temperature.
Severe and Unusual Weather
Orf, Leigh
Class Notes
Science, weather
25 ?




Popular in Severe and Unusual Weather

Popular in Science

This 14 page Class Notes was uploaded by Rhiannon Cobb on Friday September 9, 2016. The Class Notes belongs to METR 140 at University of Nebraska Lincoln taught by Orf, Leigh in Summer 2016. Since its upload, it has received 6 views. For similar materials see Severe and Unusual Weather in Science at University of Nebraska Lincoln.


Reviews for Severe and Unusual Weather Week 3 Notes


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 09/09/16
Thursday, September 8, 2016 Severe and Unusual Weather Week 3 Latent Heating, Instability, Vertical Wind Shear, Differences between tropical and extratropical cyclones - Temperature and Dewpoint • Dewpoint measures the amount of water vapor in the air - If air calls to the dewpoint, it’s saturated - If the air keeps cooling, condensation will occur, and latent heat is released. • If air is unsaturated, it cools at 10°C per 1 km - keep the dewpoint the same as it rises • If air is saturated, it cools at 6°C per 1 km - What happens to air as it rises from the surface? - Questions (Use the graph attached at the end of the notes to answer these questions) • Is there an area where the air is warmer than its environment? If so, what happens to the air in this area? - A) No; second question is irrelevant - B) Yes; air accelerates upward - C) Yes; the air keeps moving like it did before - D) Yes; air slows down its upward motion At what level does the air become saturated as it rises? • - A) Surface (0 km) - B) 1 km - C) 2 km - D) 4 km - E) It never becomes saturated 1 Thursday, September 8, 2016 • At what level does the air start to become warmer than the air around it? - A) Surface (0 km) - B) 1 km - C) 2 km - D) 4 km - E) It never becomes saturated At what level does the rising air once again become cooler than the air around it? • - A) 10 km - B) 11.5 km - C) 13.5 km - D) 16 km - E) It never becomes cooler • Does latent heating matter in the instability? - A) No, it’s stable regardless - B) Yes, there’s instability without latent heating, but not with latent heating - C) Yes, there’s instability with latent heating, but not without it - D) Yes, there’s instability with both, but more with latent heating - E) No, there’s instability regardless • if the air is unstable the surrounding air will be below the rising air - Vertical Wind Shear • Vertical wind shear is how the wind changes with speed and direction as you go up in the atmosphere - Strong vertical wind shear weakens hurricanes and prevents them from forming. - Latent Heating and Shear • Recall that hurricanes are fueled by latent heating - Weak or no shear 2 Thursday, September 8, 2016 • Latent heat release is concentrated in a small area. - The storm is essentially a “straight up and down” storm - Strong Shear • Same amount of latent heat total, but spread over a much wider area - Instead of the storm being “straight up” the wind is much stronger towards the top and is spread over a wider area and so the wind is stronger. - This is fueled by thunderstorms at the core and latent heating • Strong Vertical Wind Shear - The latent heating is spread over a wider area so the high pressure aloft is weaker, and the surface low is also weaker. - Tropical vs. Extratropical Cyclones • Hurricanes often transition to extratropical (or post-tropical cyclones as they move north) - Most of our storms come from extratropical cyclones - Should we be issuing tropical storm advisories for these post-tropical cyclones? • Symmetry - Extratropical cyclones aren’t symmetrical • (insert pictures) • Location of Thunderstorms - Are storms surrounding the core? • Most of your storms are far away from the core • (insert pictures) • Strongest Winds - Are the strongest winds near the core, and how strong? • Are near the core in a tropical cyclone. • Extratropical have weaker winds, not near the core • Lowest Pressure 3 Thursday, September 8, 2016 - Pressure can get much lower in tropical cyclones • Tropical, hurricane katrina got down to 902 mb • Extratropical this storm got down to 960 mb • Energy Source - Warm water, or difference in warm/cold air? • Tropical, draws energy from warm water and latent heating Extratropical draws energy from warm and cold temperature difference • • Upper Level Winds - Weak or strong upper level winds? • Tropical have weaker upper level winds • Extratropical near the jet stream, with strong upper level winds • Fronts - Tropical cyclones don’t have fronts • Vertical Structure - Tropical cyclone has warm air near the center (warm core) and high pressure aloft - Extratropical cyclone has cold air in the core, and low pressure/jet stream aloft • Weak/No Vertical Wind Shear - Recall that this is fueled by thunderstorms at the core and latent heating *Continues to Next Page* 4 Thursday, September 8, 2016 Review of Quizzes and Material - New Quiz 1 • What weather feature often guides the track of Atlantic hurricanes? - A) Coriolis effect - B) The gulf stream current - C) The Bermuda high • Tropical cyclones often track around the edge of the Bermuda (or azores) high - D) The north equatorial current • What is the primary source of spring for developing Atlantic tropical storms and hurricanes? - A) Easterly waves originating from Africa • Waves of low pressure coming from Africa are the most common source of spin for Atlantic tropical cyclones - B) Pacific tropical storms and hurricanes - C) Weak cold fronts from the north - D) Occluded mid-latitude cyclones • In what direction does the air to move inside the eye of a hurricane? - A) Upward - B) Downward • Air sinks downward in the eye of a hurricane - C) East - D) West - E) North - F) South • What happens if a hurricane moves over a shallow layer of warm water with cold water underneath it? 5 Thursday, September 8, 2016 - A) The hurricane rapidly intensifies - B) The hurricane warms the cold water - C) The waves bring up cold water from deeper in the ocean and leave a trail of cold water • The winds cause waves that stir up cold water from deeper in the ocean - D) The hurricane moves back south toward warm water • Where would you find the lowest surface air pressure in a hurricane? - A) Below dry sinking air, at the edge of the hurricane - B) The spiral bands - C) The eyewall - D) The eye • The lowest pressure is usually right in the middle of the hurricane, in the eye - Quiz 2 • Why does rising air sometimes cool at the moist adiabatic lapse rate? - A) The environmental lapse rate changes how the air cools - B) Latent heat release from condensation • Air cools as it rises. However, condensation releases latent heat back into the air. When condensation is occurring, rising air doesn’t cool as quickly as would if it was dry. - C)The air is stable, so the cooling is slower - D) Evaporation of water droplets releases latent heat and causes the cooling to slow • Which of these answers indicates that the air must be unstable? - A) Rising air is cooling at the dry adiabatic lapse rate - B) Rising air is cooling at the most adiabatic lapse rate - C) Rising air is cooler than the surrounding air - D) Rising air is warmer than the surrounding air 6 Thursday, September 8, 2016 • If rising air is warmer than the air around it, it is unstable and moves upward faster • Under what condition does rising air cool at the moist adiabatic lapse rate? - A) The air is stable - B) Cloud droplets are evaporating and releasing latent heat - C) The air is unsaturated but has some water vapor in it - D) The air cools to the dewpoint, becomes saturated, and continues to cool • When air is saturated and keeps cooling, condensation and latent heat release occur, which prevents the rising air from cooling as quickly as it would if it were dry • Which of the following answers is true of tropical cyclones - A) Tropical Cyclones have warm and cold fronts - B) The strongest winds in tropical cyclones are found in the jet stream, at the top of the storm - C) Tropical cyclones have their strongest winds a few hundred miles away from the eye - D) The warmest temperatures in a tropical cyclone are found in the core of the storm (warm core storm) • The warmest temperatures are in the core of a tropical cyclone; all the other answers are true of extratropical cyclones, but not tropical cyclones • How do tropical cyclones draw energy from the oceans? - A) Evaporation of spray from the waves adds more moisture to the air that can be condensed higher in the atmosphere and releases latent heat • Evaporating warm water from the ocean adds moisture and friction from the winds adds heat - B) The Coriolis effect causes ocean currents to spin, and the waves cause the clouds above them to spin, too - C) Temperature differences between the warm water at the top of the ocean and cold water beneath it are unstable and provide energy for the storm 7 Thursday, September 8, 2016 - D) Ocean water is cool as you move out of the tropics, and the temperature differences in the ocean water warms or cools the air above it, causing low pressure and strong winds, which spin because of the Coriolis effect • Which of these is the least accurate way to measure hurricane winds? - A) Satellite images • Satellite images can estimate the wind, but the other three options directly measure it - B) Buoys - C) Hurricane hunter aircraft - D) Dropsondes • Which of the following describes the primary reason that water rises along the coast in a hurricane due to storm surge? - A) Because the air pressure is low in a hurricane, there is less air pressing down on the water, so the water rises - B) Water from waves moves inland, blown by the strong winds, causing coastal flooding Strong winds push the water onshore, causing coastal flooding; this is called • storm surge - C) Extremely heavy rain causes the ocean level to rise - D) Low tide and winds in the hurricane pull the water offshore; when the hurricane winds weaken and high tide rises, the water surges back inland all at once - Review: Air Pressure • Air pressure is the weight of the air pressing down from above • We show air pressure on maps with isobars, highs, and lows • The wind is mostly along isobars, but spirals out from highs and into lows • Isobars close together mean stronger winds • Winds are clockwise around highs and counterclockwise around lows in the northern hemisphere because of Coriolis 8 Thursday, September 8, 2016 - Review: Instability • Instability is the source of energy for rising air in thunderstorms - Instability makes the air rise in thunderstorms. It fuels thunderstorms - When cold air is aloft and warm air underneath that creates thunderstorms • Very warm, humid air near the surface, below cold air, is unstable • Warm air aloft is stable • Condensation and latent heating help make rising air less dense than the air around it - Review: Hurricanes • Eye is a calm area in the center of the storm • Eyewall surrounds the eye with intense storms and the strongest winds • Latent heat release from strong storms makes the air expand upward and creates high pressure aloft • Air spirals out in the upper atmosphere, lowering the pressure at the surface - Review: Tropical Cyclone Formation • Six part checklist: **MEMORIZE THIS LIST** - Non-zero Coriolis (a little distance from the Equator) Deep (~15,000 feet) layer of moisture - Instability to fuel thunderstorms - A source of spin (like a tropical wave) 9 Thursday, September 8, 2016 - Weak vertical wind shear - Warm ocean temperatures (typically at least 28°C/82°F) The Life Cycle of Hurricanes (especially in the Atlantic) - What are the typical origins of hurricanes? • Tropical Waves • Intertropical Convergence Zone H L • Sahara Desert is VERY HOT • The Rainforests are COOLER - It is a lot hotter over in the desert part of Africa - So in these hot areas In the Sahara Desert (High Pressure in the north) and Cooler areas in the Rainforests (Low Pressure) Aloft. What happens in between these areas? • What happens to the wind in the middle? (Look at the black oval for the in- between area) - A) Wind from the north - B) Wind from the south 10 Thursday, September 8, 2016 - C) Wind from the east - D) Wind from the west - E) Nothing at all • What is a Jet? - A jet is a narrow stream of stronger winds… usually long, but not very tall or wide - The jet stream is up around 30,000 feet - In the central US we get a low level jet around 5,000 - African Easterly Jet • A jet of easterly winds about 10,000 feet above the ground. - It cuts through the area ( where the black oval is) It almost looks like a wave through the area (looks like a wave) - The waves come off the mountains and highlands in eastern africa • There are about 60 tropical waves that come off of Africa each year - Most don’t become tropical cyclones • Thunderstorms, each of these waves is a tropical wave, or an easterly wave - What happens under the high (pressure)? (Due to Jet stream between low and high pressure) • A) Nothing at all • B) High pressure forms below 11 Thursday, September 8, 2016 • C) Low pressure forms below (its called a thermal low) - The pressure goes down near the surface and thermal low forms • This is how the West African Monsoon forms Typical Global Winds - Typical Global Winds • Notice that the winds converge near the equator and the air rises - We call this the intertropical Convergence Zone or ITCZ for short • ITCZ in July - The ITCZ helps to strengthen atlantic tropical waves • It’s a common place for pacific tropical cyclones to form • Notice that the ITCZ is a bit north of the equator in most areas, and far enough north for tropical cyclones. 12 Thursday, September 8, 2016 - The ITCZ moves north in the northern hemisphere summer and south in the northern hemisphere winter • Often appears ons satellite as a band of showers and thunderstorms near the equator - What Happens over the ocean? • Notice warm water in the western atlantic and cool water in the eastern atlantic • Some of the cool water comes up from below, this is called upwelling • The gulf stream is a fast ocean current that brings warm water northward along the east coast • A similar current called the Kuroshio current is on the west side of the Pacific Ocean • How might the Gulf Stream affect tropical cyclones that move over it? - Notice the cool water in the eastern pacific • And upwelling off the coast of California • Where in the ocean would you expect the most hurricanes to form? - A) Eastern part of the ocean - B) Central part of the ocean - C) Western part of the ocean • It’s important to have warm water for these storms - D) All are equally likely • Steering currents bring tropical waves over the warmer waters in the western atlantic - When the high pressure moves west, we call it the bermuda high - Each tropical wave is an area of lower pressure and converging winds 13 Thursday, September 8, 2016 • Stronger winds around the subtropical high are steering currents for tropical cyclones. - Why do you think it's rare for hurricanes to hit the Northeast? • A) Strong vertical wind shear along the coast • B) Upper level winds guide hurricanes back out to the Atlantic and cool waters weaken them • C) Hurricanes weaken over the Gulf Stream ocean current • D) Surface temperatures are too warm under the Bermuda High and they evaporate the rain - Thermal low, associated with the north american monsoon. - Why do you think hurricanes don't hit California? • A) Cool waters off the coast • B) Winds steer hurricanes away • C) No ITCZ in the North Pacific • D) Strong vertical wind shear • E) Steering currents and cool waters 14


Buy Material

Are you sure you want to buy this material for

25 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Bentley McCaw University of Florida

"I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

Jennifer McGill UCSF Med School

"Selling my MCAT study guides and notes has been a great source of side revenue while I'm in school. Some months I'm making over $500! Plus, it makes me happy knowing that I'm helping future med students with their MCAT."

Steve Martinelli UC Los Angeles

"There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."

Parker Thompson 500 Startups

"It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.