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Flashcards in Pressure Systems Deck (15):
1

Describe the typical pressure pattern in an active pressure system

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

2

What does a surface low lead to?

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

3

What does a surface high lead to?

Divergence at the surface and consequently subsidence and an upper low

4

Where is the typical level of mean non-divergence?

14,000ft or 600hPa

5

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

The barostatic level

6

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

Neither, they are between the two

7

What is the name for a high pressure system?

Anti-cyclone

8

What are the general properties of anticyclones?

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

9

What are depressions associated with?

Strong winds, precipitation, surface convergency and convection

10

What are the general properties of depressions?

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

11

How are orographic depressions formed?

When low level airflow swirls around land features

12

What is another name for a thermal low ?

Warm low

13

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

Radiation fog

14

What are the properties of a col?

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

What are cols noted for in summer?

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