NSF North Mississippi GK-8 Weather!. Temperature You will usually see temperature measured in °F for maps of the United States Maps of foreign countries.

NSF North Mississippi GK-8NSF North Mississippi GK-8

Weather!Weather!

NSF North Mississippi GK-8NSF North Mississippi GK-8

Temperature• You will usually see temperature measured in °F for maps of the United States

• Maps of foreign countries will usually be measured in °C

NSF North Mississippi GK-8NSF North Mississippi GK-8

Relative Humidity• The relative humidity tells us how “full” the air is at the time of measurement.

• For example, 90% relative humidity means that at that moment the air is holding 90% of the maximum amount of water it could.

NSF North Mississippi GK-8NSF North Mississippi GK-8

Cloud Cover Symbols

• You will often see the circles drawn on a weather map

NSF North Mississippi GK-8NSF North Mississippi GK-8

Air MassesThere are two types of air masses:

1. Continental Polar air masses-DRY, COLD

2. Maritime Tropical air masses-

MOIST, WARM

NSF North Mississippi GK-8NSF North Mississippi GK-8

Fronts

A front is the boundary separating air masses of different densities

Fronts extend both vertically and horizontally in the atmosphere

NSF North Mississippi GK-8NSF North Mississippi GK-8

High and Low Pressure Areas

• High pressure causes air to sink

• Usually results in several days of clear sunny skies

• Air rises in low pressure areas and forms water droplets

• Usually results in rain and storms

NSF North Mississippi GK-8NSF North Mississippi GK-8

Fronts: Types of Fronts1. Cold Front: The zone where cold air is replacing warmer air

• In U.S., cold fronts usually move from northwest to southeast

• Air gets drier after a cold front moves through

NSF North Mississippi GK-8NSF North Mississippi GK-8

Fronts: Types of Fronts2. Warm Front: The zone where warm air is replacing colder air

• In U.S., warm fronts usually move from southwest to northeast

• Air gets more humid after a warm front moves through

NSF North Mississippi GK-8NSF North Mississippi GK-8

Fronts: Types of Fronts3. Stationary Front: When either a cold or warm front stops moving

• When the front starts moving again it returns to either being a cold or warm front

NSF North Mississippi GK-8NSF North Mississippi GK-8

Fronts: Types of Fronts4. Occluded Front: Formed when a cold front overtakes a warm front

• This occurrence usually results in storms over an area

• In U.S., the colder air usually lies to the west

NSF North Mississippi GK-8NSF North Mississippi GK-8

Clouds: Types of Clouds1. High-Level Clouds: Usually found at greater than 20,000 ft.

Usually made of ice crystals

Examples include Cirrus, Cirrostratus

NSF North Mississippi GK-8NSF North Mississippi GK-8

Clouds: Types of Clouds2. Mid-Level Clouds: Usually found between 6,500 and 20,000 ft.

Usually made of water droplets, but can be made of ice

Example is altocumulus

NSF North Mississippi GK-8NSF North Mississippi GK-8

Clouds: Types of Clouds3. Low-Level Clouds: Usually found lower than 6,500 ft.

Low, lumpy clouds that produce weak to moderate precipitation

Examples include Nimbostratus and Stratocumulus

NSF North Mississippi GK-8NSF North Mississippi GK-8

Clouds: Types of Clouds4. Vertically developed: These clouds are thick and puffy and extend very far upwards

Examples include Cumulonimbus and Fair Weather Cumulus

Ordinary Cumulus clouds can quickly become Cumulonimbus clouds that start strong thunderstorms

NSF North Mississippi GK-8NSF North Mississippi GK-8

Clouds: Types of Clouds5. Other: These are miscellaneous clouds

These clouds do not really fit into any category, and all have different characteristics

Examples include billow clouds, contrails, mammatus, orographic, and pileus

NSF North Mississippi GK-8NSF North Mississippi GK-8

Weather Maps: Pressure & Temperature

NSF North Mississippi GK-8NSF North Mississippi GK-8

Weather Maps: Doppler Radar Maps

NSF North Mississippi GK-8NSF North Mississippi GK-8

Summary Temperature: Usually in °F

High pressure areas cause sunny weather; low pressure areas cause rain and storms

Two Types of air masses:

1. Continental Polar

2. Maritime Tropical

NSF North Mississippi GK-8NSF North Mississippi GK-8

Summary (continued) types of fronts:

1. Cold2. Warm3. Stationary4. Occluded

types of clouds:1. High Level2. Mid Level3. Low Level4. Vertically developed5. Miscellaneous

NSF North Mississippi GK-8NSF North Mississippi GK-8