Upper Level Winds and Jet Stream

Question 1

Define Jet Stream

Answer 1

A jet stream is a relatively narrow, rapidly flowing, ribbon-like stream of air embedded in main air flow.

Question 2

How long, thick and wide is a jet stream?

Answer 2

Thousands of miles long, a few thousand feet thick and a few hundred feet wide.

Question 3

How fast must a jet stream be?

Answer 3

At least 60 kts.

Question 4

How do jet streams develop?

Answer 4

When there is a strong horizontal temperature gradient through a deep layer of the atmosphere.

Question 5

________ temperature differences cause wind speeds to increase with height.

Answer 5

Horizontal

Question 6

True of False: The stronger the horizontal temperature difference, the greater the increase in wind speed aloft.

Answer 6

True

Question 7

Isotherms run approximately is what direction?

Answer 7

West to East

Question 8

Do upper level winds blow parallel or perpendicular to isotherms?

Answer 8

Parallel

Question 9

_____ is more dense than _____ air.

Answer 9

Cold / Warm

Question 10

Does pressure increase or decrease more rapidly with height in cold air?

Answer 10

Decreases more rapidly.

Question 11

The _____ the horizontal temperature gradients, the greater the increase of wind speed with height.

Answer 11

Stronger

Question 12

Consider a pressure surface between warm and cold air. Towards which does the surface slope?

Answer 12

Cold surface

Question 13

Horizontal temperature causes a large slope in upper pressure surfaces. Does this result in a strong or weak PFG?

Answer 13

Really strong.

Question 14

Wind becomes parallel and much stronger North or South or the front?

Answer 14

North

Question 15

Which of the following jets is the highest, lowest and in-between in altitude Maritime, Arctic and Polar jet?

Answer 15

Highest: Polar
In-between: Maritime
Lowest: Arctic

Question 16

True or false?

Jets will never merge into 2 or even 1 wider jet.

Answer 16

False

Question 17

Define Jet Axis

Answer 17

Strongest winds at a particular level. Ex. 250hPa

Question 18

Jet Core

Answer 18

The jet axis where the wind speed is maximum.

Question 19

Jet Maximum

Answer 19

A point along the axis where the wind speed is at a maximum.

Question 20

Which side along a surface front does a jet stream exist?

Answer 20

Poleward side

Question 21

True or False?

The jet stream is in the colder air mass.

Answer 21

False, it is in the warm air mass.

Question 22

True or False?

Jet streams are positioned above the tropopause.

Answer 22

False, they exist below it.

Question 23

Jet streams are associated with which type of cloud?

Answer 23

Cirrus

Question 24

Which edge, either cold or warm, is the jet stream near in a cirrus cloud deck?

Answer 24

Cold edge

Question 25

Which side of the jet is the cirrus cloud deck on, warm or cold?

Answer 25

Warm

Question 26

Does the wind increase or decrease away from the jet?

Answer 26

Decreases

Question 27

True or False? Horizontal wind shears are stronger than vertical around the jet.

Answer 27

False

Question 28

Is there a difference in HWS on the cold and warm side of the jet? if so, which one is stronger and by how much.

Answer 28

Yes, the cold air side is 3X stronger.

Question 29

In winter, temperature contrasts between air masses is stronger or weaker?

Answer 29

Stronger

Question 30

The tilt of the North Pole away from the sun in winter does what to the following regarding jets: Latitude Height Wind Speed No. of Jets

Answer 30

Moves further south Lowers Stronger 3 instead of 2

Question 31

Are thermal winds stronger in winter or summer?

Answer 31

Winter

Question 32

What are the two types of Non-Frontal jet streams?

Answer 32

Arctic Stratospheric & Subtropical

Question 33

Solar heating at the equator causes which non-frontal jet stream?

Answer 33

Subtropical

Question 34

True or False? Both non-frontal jet streams are westerly

Answer 34

True

Question 35

Which non-frontal jet stream is higher?

Answer 35

Arctic Jet Stream