Chapter 13 Thunderstorms

Question 1

What is the most hazardous phenomenon for aviation

Answer 1

Thunderstorm

Question 2

When is the thunderstorm reported

Answer 2

When a thunderstorm is heard

Question 3

Types of TS

Answer 3

Heat, frontal, steady state and MCC ( mesoscale convective complex )

Question 4

Frontal TS

Answer 4

Occurs at a cold front something maybe warm front
It happens due to the vigours UPlift of moist air along or ahead a cold front
Happens at day or night

Question 5

Squall lines

Answer 5

Lines of thunder storms develop

Question 6

Air mass TS

Answer 6

Happens cuz of intense heating and when cold front passes and CONVERGENCE due to low pressure

Question 7

Where does air mass TS develop

Answer 7

Afternoon at plains

Question 8

Steady state TS

Answer 8

They are strong in mature stage and lasts for hours

Question 9

MCC TS

Answer 9

It is clusters of TS
Lasts for 6 to 24 hr
New TS develops inside this
They form near fronts and tropics in ITCZ

Question 11

Single cell TS

Answer 11

Ex : heat or air TS
They have one main up draught
Are rarely severe
Occurs after cold front in winter

Question 12

Multi cell cluster

Answer 12

They form clusters due to convective update
Near mountain ranges and strong cold front
Each cell lasts for 20 mins

Question 13

What is a strong squll line called

Answer 13

Derecho

Question 14

Super cell

Answer 14

Have both up and down draught due to WS

Question 15

Favourable conditions for TS formation

Answer 15

It is a instability phenomenon
So steep lapse rate
High humidity
Trigger action like a lifting motion like fronts , convergence radtion and ect

Question 16

Cumulus stage

Answer 16

Formation Cu clouds and then Cu to Cb
Only up draught throughout the cloud
Turbulence and icing occurs in this stage
Entrainment happens which is inflow of environmental air into the cloud

Question 17

Mature stage

Answer 17

Aanvil form on the top of the clouds cuz it reached the tropopause and spreads out
Precipitation occurs in this stage
Up and down draught co exists
It is a multi cell line and if sufficient WS happens it becomes a super cell if little WS happens it dissipates tornado may develop
It last for 20 to 40 mins

Question 19

Gust front

Answer 19

In the mature stage the down draught near the ground spreads the cloud horizontal and form a arc shape it is called gust front

Question 20

Dissipating stage

Answer 20

Only down draught
So no growth for the cloud
It may rain but it goes away

Question 21

Clouds which emanate from the CB

Answer 21

Roll clouds ,shelf clouds

Question 22

What is the structure of the severe TS

Answer 22

Tilted

Question 23

Movement of the TS

Answer 23

700 to 500hpa wind influence the movement

Question 24

What jet stream is important for the dev for TS

Answer 24

Upper level jet stream

Question 25

Aviation hazards of TS

Answer 25

Turbulence Icing WS Squall Draught Noise Lighting Dark Hail Instrument error Gust Heavy showers

Question 26

Air pocket

Answer 26

It is s up or a down draught which occurs by the local regions of warm and cold air and high and low pressure area

Question 27

Downbust

Answer 27

It is a severe down draught

Question 28

Micro bursts and Marco bursts

Answer 28

Locaizied severe down draught with dia less than 4 and Marco busts with dia more than 4km

Question 29

Causes of micro burst is

Answer 29

Vigra

Question 30

Micro burst is cause in

Answer 30

CB ,heavy rain ,virga

Question 31

How to avoid micro bursts

Answer 31

Don't fly below CB, TS and virga

Question 32

When are DS formed

Answer 32

Pre monsoon at N india It is called andhi Forms just like TS

Question 33

Classification of DS

Answer 33

Light DS upto 21 kts and 500 to< 1000 visi Moderate DS upto 22 to 40kts 200to < 1000visi Severe dust Strom. > 40 > 200m

Question 34

Norwester

Answer 34

Happens in pre monsoon at NE states These are storms They form squall lines

Question 35

What is s tornado of sea is called

Answer 35

Water spout