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Flashcards in Cyclonic Development Deck (73)
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1

We can get an idea of the instantaneous trend for a pressure center from the _______ in its vicinity.

Pressure tendency

2

List the 3 factors that affect the central value of a low

Topography
Diurnal pressure changes
Diabatic influences

3

Central pressure values are not always accurate in ________ regions

Mountainous

4

List the 6 factors which contribute to divergence and convergence in a developing low pressure system.

Sensible heat transfer
Latent heat transfer
Surface vorticity
Horizontal thermal advection
Horizontal vorticity advection
Heat transfer by vertical motion

5

Maximum WAA and minimum CAA =

Divergence aloft

6

Maximum CAA and Minimum WAA =

Convergence aloft

7

Sinking air(compression) will contribute to:

Atmospheric Divergence

8

Areas of maximum heating will produce :

Divergence

9

Local heating due to latent heat release will contribute to:

Atmospheric divergence

10

In the free atmosphere, upper level divergence and low level convergence tends to ________ surface pressure

Lower

11

The atmosphere is said to be baroclinic when there is:

a horizontal temperature gradient on an isobaric surface

12

The strength of a baroclinic zone depends mainly on:

the thermal contrast or the temperature gradient

13

The thermal contrast is indicated by:

the number of isotherms in the baroclinic zone

14

List the 5 stages in the life cycle of a baroclinic depression:

Formation
Development
Maturity
Occlusion
Dissipation

15

When contributing factors have comibned in such a way that their net effect is to generate surface vorticity, it is known as

Cyclogenesis

16

Some good indicators of the formation of a new low center are:

-New vorticity center developing at 500 hpa
-Intensification of vorticity and thickness advection over a center where there was none previously
-A kink developing in a baroclinic zone
-Awareness of favorable areas of cyclogenesis
-Changing edges of mid level cloud

17

4 important points about formation are:

-Baroclinic zone associated with a "leaf" of CI cloud
- Cyclonic circulation is onset
-A frontal wave crest forms along the baroclinic zone
- An ill defined S appears along CI back edge

18

Most baroclinic lows which are developing are associated with:

A 500 hpa short wave trough located 3 to 5 degrees of longitude behind the low.

19

Surface lows are guided, in general, by the:

500 hpa flow

20

Development begins when the surface vorticity increases due to the production of:

Divergence aloft

21

When the lag between the thickness and contour patterns is about a quarter of a wavelength we have:

baroclinic instability

22

As the wave matures, The following features with the depression occur:

-The low has deepened and intensified considerably
-The wave amplitude has grown on the baroclinic zone
-Isotherms are curved in the direction toward which the air is moving
-The amplitude of the upper trough and ridge is increasing and will reach a peak at the end of this stage
-East of the low WAA has increased considerably

23

The mature system has a ______ shape form

comma

24

the following dynamic features are to be noted:

-The direction of motion is parallel to the isobars in the warm sector
-The thermal wave is rotating counter clockwise about the center

25

What are 5 indicators that occlusion is occuring?

-Deep Upper trof due to CAA
-A few closed contours form the upper trof
-Surface low loses thermal support
-Cold air appears to undercut warm front
-Cloud stretches along trowal/surface front

26

In the dissipation stage, due to friction and the static stability combined with cooling of the air column, _________ is increasing in both the boundary layer and the free atmosphere.

Convergence.

27

during the depression stage, the central pressure is _______ and the depression is ________

Rising, Filling

28

Indicators of dissipation are:

-Surface low moves toward 500 hpa heights
-The air column cools down and produces a cold low
-Convergence increases in the whole air column
-Central pressure usually rising

29

List the 5 methods that can be used to indicate the motion of a low pressure system

-History
-Isallobaric pattern
-isobaric flow
-baroclinic zone
-500hpa flow

30

With an extremely asymmetrical low pressure system, which way will the center tend to move?

Along the longest axis, with very little adjustment for the isallobaric field.