Depressions

I just cannot carry on !

Or the wet and windy ones

Characteristics of a depression

On the white board you need to list as many characteristics of a depression that you can think of …

Go on take a chance !

Characteristics of a depression

Rain …. And more rain Strong winds Low pressure – usually

below 1000mbs Closed isobars that are

close together on a weather map

Isobars are close together giving steep pressure gradients

How do depressions form ?

Two air masses meet along the POLAR FRONT

Polar Maritime Air from the North Atlantic which is cold dense and moist meets

Tropical Maritime Air from the SW which is warm, less dense and also moist.

The mixing of these creates the depression.

This is what a depression can look like approaching the UK

Formation of depressions

Initially make notes on IntroductionWarm FrontCold FrontOccluded Front or OcclusionTroughCut & paste their diagrams into your

word “notes” – use the link below.Met Office: Weather systems

Formation of depressions

Use the link at the end of this slide

now explain how a depression forms and dies (the four stages)

– you could cut & paste some of the diagrams/tables but put the writing into your own words - make sure you read & understand them !

Met Office: Weather systems

Typical weather sequence of a depression

You must be able to describe (and explain) the sequence of weather as the warm front approaches, passes, you enter the warm sector and then the cold front passes.

The table is on the website is very useful !Take note of the weather maps – you must

be able to recognise a depression from these. Link is below.

Met Office: Weather systems

Other places to look on the website

Read through the link below – take note of the fronts & what the various weather maps show – in an exam you will probably only get a b/w copy !

Met Office: Weather charts

Depressions – check list

Make sure that you have notes and/or diagrams which show

The characteristics of a depressionHow they form (and die !)The sequence of weather as they passWhat they look like on a weather

map/satellite photo Can you explain as well as describe ?

Location of Presentation

Make a note of this !

You need to use this presentation for your next few lessons

It is at

Depts. on Upper (U) > students > upper depts > Geography > depressions.

Keep it safe !!!

Further links – look at the diagrams and make further notes from

S-cool.co.uk A level & AS revision > Geography > Weather Conditions