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Weather Fundamentals

Composition of the Atmosphere​

Layers:

Thermopause Thermosphere Mesophere Stratosphere Ozone layer Troposphere

Weather happens in the Troposphere

Atmosphering Circulation​

Cause of all weather is uneven heating of the earth's surface

Coriolis Force​

Wind caused by earth's rotation

Atmospheric Pressure​

Sea level 14.7ls

Every 1000ft, pressure drops about an inch of mercury

Aneroid wafers

Winds and Currents​

The air over the sea heats up more slowly than over land.

High pressure - usually brings better weather Move clockwise outwards and downwards (COD) COD

Low pressure - brings worse weather counter clockwise, inwards, upwards??

Bom cyclones

To get a tailwind You want to be south of a low pressure, north of a high pressure

Effects of Obstructions on Winds​

Obstructions can cause downdrafts

Mountain Winds​

Cross mountains at a 45degree angle - makes it so you can turn around without having to turn as much (90 egrees instead of 180)

Winds above 20kts gets ...scary??

Windshear​

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Spot #1 you get an increase in performance

If you had a headwind and then

Don't fly if there's any windshear.

Fly a landing approach faster in wind shear

Atmospheric Stability​

The atmosphere's ability to resist vertical lift

Adiabatic Heating and Cooling​

2 degrees / 5.4 F temperature drop per every 1000 ft of altitude

Moisture and Humidity​

Relative Humidity

RH represents the amount of water in air in percentage

Gives us insight into if cloud are going to form

Dew point

At 100% humidity, there will be some sort of visible moisture

Temerature Inversions​

When you go up in altitude and it gets warmer instead of cooler

Cloud Characteristics​

Stratus clouds: Low level, stable clouds Stratocumulous

Towering cululus or cumulonimbus are tall and have a lot of

Stratiform Clouds: The blanket clouds that stretch a ways

Cumulus clouds are fluffy

Air Masses​

Cold fronts​

Usually bring worse weather and move faster

All fronts bring wind changes and temperature changes

Warm Front​

Occluded Front​

When a cold from overtakes a warm front and everything mixes together

Thunderstorms​

Three stages

  • Cumulus
  • Mature
  • Dissipating
    • Most dangerous because of down drafts

3 ingredients

  • moisture
  • unstable air
  • lifting force

If there is a thunderstorm, you're supposed to stay 50-60 nm away. They can throw hail really, really far. (About 15m?)

Characterized by the anvil top shape

Water molecule is sent up. When it goes up, it becomes ice. The ice falls, hits the water molecules. When it hits, it creates static electricity.

Icing​

Three types

Clear icing: rain hits aircraft and then freezes Rime: Freezes right away. Causes the most drag and decreases lift Mixed

Want to land if you start to get icing

Fog​

Radiation Fog​

Think zombies on farm fog

Forms on clear nights with low temp and dew point spread is low/small

Overnight, air cools to it's dew point, condenses and creates fog

Advection Fog​

Cold air mass moving over a warm air mass, fog happens from the cooling "Marine layer"

Steam fog​

Air that moves over a warm body of water, heats up, forms steam. Less common

Upslope Fog​

Air mass is forced up a hill, cooled to it's dew point

Precipitation fog​

Extra fine, small rain particles

Freexing fog​

Less common around here.

Air particles frozen and suspended in the air

Need to know -

Microbursts Advection and radiation fogs Thunderstorms Vergo clouds - indication that there's a microburst

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