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Flashcards in Pressure Systems Deck (15)
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1
Q

Describe the typical pressure pattern in an active pressure system

A

Generally the pressure at the surface and the tropopause will be opposite

2
Q

What does a surface low lead to?

A

Convection at the surface and rising air which must diverge in an upper high

3
Q

What does a surface high lead to?

A

Divergence at the surface and consequently subsidence and an upper low

4
Q

Where is the typical level of mean non-divergence?

A

14,000ft or 600hPa

5
Q

What is the level of mean non-divergence otherwise referred to as?

A

The barostatic level

6
Q

Are the pressure systems highs or lows at the barostatic level?

A

Neither, they are between the two

7
Q

What is the name for a high pressure system?

A

Anti-cyclone

8
Q

What are the general properties of anticyclones?

A

Large, slow to form or dissipate and stationary or slow moving

9
Q

What are depressions associated with?

A

Strong winds, precipitation, surface convergency and convection

10
Q

What are the general properties of depressions?

A

Small, 300NM, active, form rapidly, move at fair speeds and fill rapidly when they die

11
Q

How are orographic depressions formed?

A

When low level airflow swirls around land features

12
Q

What is another name for a thermal low ?

A

Warm low

13
Q

Over land in winter a col produces deteriorating visibility. What might this be due to?

A

Radiation fog

14
Q

What are the properties of a col?

A

Located between 2 highs and 2 lows. Virtually no low level wind. Anti-cyclone type weather. Light winds, clear skies and an inversion at low level.

15
Q

What are cols noted for in summer?

A

Air mass thunderstorms. Isolated, thermally generated CBs that pop up all over the area.