weather jf

of 48 /48

Upload: frjo0802

Post on 04-Aug-2015




2 download

Embed Size (px)


Page 1: Weather jf


Page 2: Weather jf
Page 4: Weather jf

Pressure Recall the pressure

crushing the pop can from the last unit

The sum of the forces from the moving air molecules over an area

Average Sea level pressure is 1010mb

Page 5: Weather jf

What do these mean?

L- Low pressure, rising motion

of the air H-High Pressure, sinking motion of the air

Page 6: Weather jf

So What’s Going on Here?

What is wind?

What would we expect the wind to look like in this example?


Page 7: Weather jf


Page 8: Weather jf

Instead we see this…

Page 9: Weather jf
Page 10: Weather jf

Coriolis Effect

Caused by the Earth’s Rotation Causes the Rotation of air around pressure

centersOpposite effects on southern hemisphereSimpsons video Example

Page 11: Weather jf

• Air rises at a Low Pressure Center

• Associated with cloudy and windy weather

• North Pole Loop

• Air sinks at a High Pressure Center

• Associated with nice and calm weather

Page 12: Weather jf


Isotherm Line of equal

temperature Isobar

Line of equal pressure

Gradient is shown by lines drawn close together Very important to

find fronts!

Page 13: Weather jf

Fronts Leading Edge of different air mass

Temperature, humidity, wind direction

4 types Cold Front

Warm Front

Occluded Front


Page 14: Weather jf
Page 15: Weather jf

Cold Front

Brings in colder, drier air with a sudden change in wind speed and direction

Page 16: Weather jf

Warm Front

Brings warmer, more humid air with change in wind direction

Page 17: Weather jf

Occluded and Stationary Fronts

Occluded Front• When cold front and warm

front run into each other• Large amount of

precipitation is possible

Stationary Front• Boundary between two

air masses• Neither air mass has

enough force to move the other

Page 18: Weather jf

Station Model

Page 19: Weather jf

Reading Pressure

If 1st number is less than 5, you put 10 in front

If 1st number is more than or equal to 5, you put 9 in front

Page 21: Weather jf
Page 22: Weather jf

Weather at Fronts Cold Fronts

Clouds, rain/snow in narrow band right on frontal boundary

Clear skies quickly follow frontal passage with strong N/NW winds

Warm front Thin clouds/blanket of clouds with light rain possible

ahead of the frontal boundary Winds shift to the south

NW (top left) corner of Low Pressure Center Heavy rain/snow fall possible Caused by upper air similar to occluded front

Page 23: Weather jf
Page 24: Weather jf

Jet Stream

Pressure Centers control where fronts go

Prevailing winds and the jet stream control where pressure systems go


Page 25: Weather jf


Page 26: Weather jf

What are clouds made of?

Clouds are made of very small droplets of water or ice crystals.

Page 27: Weather jf

How do clouds form?

Air cools as it rises, this causes water vapor that is in the air to condense into a liquid

What causesAir to rise?

Page 28: Weather jf
Page 29: Weather jf
Page 30: Weather jf

Types of Clouds

Cumulus “Puffy” with flat base Can grow very tall Time lapse of growth

Another Time Lapse Video

Page 31: Weather jf

Stratus Clouds Uniform “blanket” layer Usually dark gray Can form at different altitudes

Example: altostratus=middle altitude Cirrostratus=high altitude

Page 32: Weather jf

Cirrus Clouds Thin “wispy” clouds Very high altitude Made of ice crystals

Page 33: Weather jf

Special Cases

Precipitation When the cloud drops get too large to stay

suspended Gives the cloud a new name Can be liquid or ice

Cumulonimbus nimbus cloud that is producing precipitation

Nimbostratus Stratus clouds that produce precipitation

Page 34: Weather jf
Page 35: Weather jf

Life of a Rain Drop

Page 37: Weather jf

Severe Weather When normal weather occurrences (wind,

rain) become more powerful than normal.

This creates dangerous conditionsfor people and property

These storms require very specificIngredients for form

Page 38: Weather jf

Ingredients for Severe Storms

• High dew points (humid air)

• High Temperature

• Unstable air (cool air aloft)

• Lifting mechanism


Page 39: Weather jf

Squall Line

Line of thunderstorms caused by cold front movement

Several storms may be severe

Page 40: Weather jf
Page 41: Weather jf
Page 42: Weather jf
Page 43: Weather jf
Page 44: Weather jf

Cumulus Nimbus

Tallest, most powerful cloud and produces severe storms

Page 45: Weather jf

Squall line

Page 46: Weather jf

Super Cell Storms

Cumulonimbus clouds with rotation

Extra ingredient required is wind sheer

Wind sheer is the change in wind speed and direction as you change altitude

Page 47: Weather jf
Page 48: Weather jf