Meteorology - Lecture 23 &2 4 - Exam 3

_______ are defined as a local storm produced by a cumulonimbus cloud and MUST HAVE thuder and lightning

Thunderstorm

Severe thunderstorm ingredients (SLIM)

1. Shear

2. Lift

3. Instability

4. Moisture

_______ is the rate at which wind velocity changes from point to point

Shear

3 types of shear

1. Speed shear (only speed changes)

2. Directional shear (only direction changes)

3. Combination (both change)

Speed shear is very important for severe thunderstorm development as it tilts the ________ (rapidly rising air that forms clouds)

Updraft

Speed shear can also create _______ air in the atmosphere, allowing for supercells to form

Rotating

Thunderstorm ingredients (LIM)

1. Lift

2. Instability

3. Moisture

In an unstable atmosphere, weather can change suddenly and be _______

Severe

________ ________ ________ ______ (CAPE) is the amount of fuel available to a developing thunderstorm.

Convective Available Potential Energy

3 types of thunderstorms

1. Ordinary cell (air mass)

2. Multicell

3. Supercell

Ordinary cells thunderstorms are often called ___ - __ storms

Pop-up

2 types of multi-cell thunderstorms

1. Multi-cell line (Squall line)

2. Multi-cell Cluster (mesoscale convective complexes)

Supercell thunderstorms are the _____ severe

Most

Life cycle of an ordinary cell thunderstorm

1. Developing stage

2. Mature stage (most severe)

3. Dissipating stage

This image shows the _______ stage of an ordinary cell thunderstorm

Developing

This image shows the _______ stage of an ordinary cell thunderstorm

Mature

This image shows the _______ stage of an ordinary cell thunderstorm

Dissipating

In multi-cell thunderstorms, new cells develop as a result of _____ ______ _____ (outflow boundary)

Cold pool forcing

Multi-cell storms tend to form in a region of ______ shear

Strong

_____ ____ are storm-scale cold air masses

Cold pool

Cold pools can either…

1. Initiate thunderstorm development

2. Inhibit thunderstorm development

A _____ front is an outflow boundary coming from a storm (wind picking up before storm)

Gust

______ ______ (Arcus cloud) may form when warm, moist air rises along the forward edge of the gust front.

Shelf cloud

A _____ _______ (Volutus) forms on rare occasions, where a narrow, elongated cloud will form along the gust front but detach from the thunderstorm base

Roll cloud

A ________ is a severe, localized downdraft that can be experienced beneath a severe thunderstorm.

Downburst

2 types fo downbursts

1. Microburst

2. Macroburst

A microburst has winds spanning _____ than 4km

LESS

A macroburst has winds spanning _____ than 4km

MORE

Multi-cell thunderstorms may form as a line of thunderstorms called a _____ _____

Squall line

A ___ ____ is a radar signature of a squall line that “bows out” as winds fall behind the line and circulations develop on either end. Possibly forming brief tornadoes

Bow echo

________ __________ ________ (MCCs) are systems where conditions are favorable for convection, allowing for growth of thunderstorms

Mesoscale Convective Complexes

___________ thunderstorms are an often dangerous convective storm with a single rotating updraft which persists from a longer period of time.

Supercell

A supercell is made unique from all thunderstorms because it contains a _________

Mesocyclone

A mesocyclone is a deep, persistent, and rotating _______

Updraft

To be classified as a mesocyclone, you need…

1. Diameter

2. Vertical depth

3. Duration

4. Minimum velocity

Speed and directional shear work together and creates a ________ tube, which forms a supercell

Rolling

3 types of supercells

1. Classic (CL) (MAJORITY)

2. High precip (HP)

3. Low precip (LP)

High precipitation supercells have updraft on the _____ flank of the storm

Front

Low precipitation supercells have updraft on the _____ flank of the storm

Rear

____ clouds are lowerings forming below the updraft base of a cumulonimbus cloud

Wall

A wall cloud is _______ a precursor to a tornado, which usually for within the wall cloud

Sometimes

Wall clouds associated with potentially severe storms can…

1. Last more than10 mins

2. Visibly rotating

3. Lots of rising and sinking motion

The ___ (Lid) is a layer of relatively warm air aloft, which suppresses or delays the development of thunderstorms.

Cap

Thunderstorms may form along OR just east of a boundary called a __________

Dryline

_______ is a result of extreme heating causing air to expand explosively, causing a loud crash called thunder

Lightning

4 types of lightning

1. Intra-cloud

2. Cloud-to-cloud

3. Cloud-to-Air

4. Cloud-to-ground