MEA 2 Study Guide

CCN

Tiny particles that water vapor condenses onto to form clouds

Cloud droplet

Small liquid water particle formed by condensation

Rain droplet

Large droplet formed through collision and coalescence

Collision and coalescence

Process where droplets collide and merge to form larger drops

Bergeron process

Ice crystals grow at the expense of supercooled water droplets

Freezing rain

Rain that freezes upon contact with a cold surface

Sleet (ice pellets)

Frozen raindrops that refreeze before reaching the ground

Hail formation

Occurs in strong updrafts that carry ice particles up and down

Radar reflectivity

Measurement of precipitation intensity using radar

Mean sea level pressure

Pressure adjusted to sea level for comparison

Isobars

Lines connecting equal pressure

Pressure gradient force

Force that moves air from high to low pressure

Coriolis effect

Deflection of moving air (right in Northern Hemisphere)

Friction

Slows wind and changes its direction at surface

Cyclonic flow

Counterclockwise flow around low pressure (Northern Hemisphere)

Anticyclonic flow

Clockwise flow around high pressure (Northern Hemisphere)

Ridge

Area of high pressure aloft

Trough

Area of low pressure aloft

Wind direction

Named for where the wind comes from

Sea breeze

Cool air moves from water to land during day

Land breeze

Cool air moves from land to water at night

Downslope winds

Warm and dry winds descending mountains

Monsoon

Seasonal reversal of winds

Hadley cell

Circulation between 0–30 degrees latitude

Ferrel cell

Circulation between 30–60 degrees latitude

Polar cell

Circulation between 60–90 degrees latitude

Jet stream

Fast-moving air current caused by temperature gradients

El Niño

Warmer-than-normal Pacific waters

La Niña

Cooler-than-normal Pacific waters with strong trade winds

mT air mass

Warm and moist

cP air mass

Cold and dry

cT air mass

Hot and dry

Cold front

Cold air pushes under warm air

Warm front

Warm air rises gradually over cold air

Occluded front

Cold front overtakes warm front

Midlatitude cyclone

Storm system that forms along fronts

Cyclone life cycle

Stationary → Wave → Mature → Occluded → Dissipating

Polar low

Small, intense storm in cold regions

Strong cyclones

Form from strong temperature gradients

Order of droplet size

CCN → Cloud droplet → Rain droplet

Warm cloud droplet growth

Collision and coalescence

Ice crystal growth

Bergeron process

Freezing rain forms when

Rain freezes on contact with surface

Hail size depends on

Updraft strength

Radar reflectivity shows

Precipitation intensity

Why use mean sea level pressure

To compare pressure regardless of elevation

Close isobars indicate

Strong winds

Pressure gradient force direction

High to low pressure

Coriolis effect in NH

Deflects right

Surface winds differ due to

Friction

Cyclonic flow direction NH

Counterclockwise

Wind direction is based on

Where it comes from

Sea breeze cause

Land heats faster than water

Downslope winds are

Warm and dry

Monsoon definition

Seasonal wind reversal

Three-cell model

Hadley Ferrel Polar

Jet streams form from

Temperature gradients

El Niño condition

Warm Pacific water

La Niña condition

Strong trade winds and cool water

mT air mass weather

Warm moist

cP air mass weather

Cold dry

Cold front behavior

Cold air undercuts warm air

Warm front weather

Light steady precipitation

Occluded front forms when

Cold front overtakes warm front

Cyclones form along

Fronts

Cyclone first stage

Stationary front

Strong cyclones caused by

Strong temperature gradients

Polar lows are

Small intense cold storms

High radar reflectivity means

Heavy precipitation

Rising air in low pressure causes

Cloud formation

Close isobars mean

Faster wind

Thunderstorms most likely with

Cold front

Friction effect on wind

Slows and redirects

Jet streams located at

Air mass boundaries

Hot dry air mass

cT

Ridge means

High pressure

Trough means

Low pressure

Updraft effect on hail

Makes it larger