Chapter 19 - Non-Frontal Depressions Flashcards
Where do cold core lows occur, what do they look like and what do they show as on an isohypes chart?
(Polar low) at a polar front depression.
They create a marked lows higher up in isohypse charts
Where do warm core lows occur, what do they look like and how can they be seen on isohypes charts?
(thermal low), in TRS
It is dependant on the difference in pressures around the core.
Where do warm core highs occur, what do they look like and how can they be seen on isohypes charts?
Sub tropical anti-cyclones.
They create marked high zones on isohypes charts
Where do cold core highs occur, what do they look like and how can they be seen on isohypes charts?
In Canada and Syberia in winter.
It is dependant on the pressures around the core, but they may not be seen at all.
What is a cold pool, what kind of weather is to be expected and how does it show on surface pressure charts?
A cold pool is a pool of cold air left over when a polar jet stream meanders and then reconnects with itself.
Thunderstorms and hail showers can be expected.
It depends on the pressures aroud the cold pool but it my not show on a surface pressure chart.
What are easterly waves/african easterly waves and what can they result in?
They are troughs of low pressure created by the convergance of warm dry air flowing off the SW coast of Africa and warm moist air flowing off the Atlantic.
This causes massive uplift which can lead to TRSs.
What is required for a TRS to form?
Ocean temperatures above 26degC (in summer or autumn)
CF so usually 10-20 lat.
A trigger (ITCZ or easterly waves)
What are the 4 stages of a TRS, what are their classifications during each and when do they terminate?
Formative stage - tropical depression
Immature stage - tropical storm
Mature stage - TRS
Decaying stage.
They can terminate at any stage if conditions do not favour development.
What are the characteristics of the formative stage of a TRS?
Condensation divergence aloft causes surface pressure to deepen below 1000mb
Winds are up to 34kts
Eye forms
Classidied as tropical depression
What are the characteristics of the immature stage of a TRS?
Central pressure is less than 1000mb
Wind speed is 34k-63kts
Surface pressure continues to fall
Classified as tropical storm.
What are the characteristics of the mature stage of a TRS?
Hurrican force winds - 64+kts
Up to 200nm from centre
In NH gales and bad weather extend further on the right of the path.
Classified as TRS
What are the characteristics of the decaying stage of a TRS?
Surface pressure starts to rise
Affected area reduces in size
Dissipates over land
Moves to higher latitudes.
Why is the weather on the right side of a TRS in the NH worse than in the left?
The wind speed adds with the travelling speed to create even stronger winds.
What is the designation of a TRS in the Caribean & Eastern Pacific?
A Hurricane
What is the designation of a TRS in the South China sea & Western North Pacific?
A Typhoon
