Weather

Weather Pattern

https://www.aviationweather.gov/


1. Stable and unstable air
2. Air masses and fronts

Stable and unstable air

Stability of Atmosphere

• Hot air is light that cold air and it rises
• The lifted air continue to rise and is refer to as unstable atmosphere it is measure by the lapse rate
• Standard lapse rate - Decrease 2 Deg C for each 1000 feet in altitude increase
• If it decreases more quickly - Unstable air
• If it decreases less quicker - Stable air

Temperature affect the stability of atmosphere

Add mixture decrease stability
moisture light that air .. the air density

remove moisture increase stability
moisture mremove density - increase stability

stable air resist rising

Stable air - stable air rises up the slope produces stratus clouds, smooth air, steady precipitation

Unstable Air
- Turbulance
- Good surface visibility,
- Moisture unstable airmass result in cumulus clouds and showery precipitation

Keep on rising -
lots of vertical development

2. Air Masses and Fronts

Airmass - huge body of air similar temp and moisture
source region
- cold  polar
- Warm

Continental - dry
Maritime tropical - warm moist

Factor affecting
speed
temperature deference
depth

FRONT
Boundary between air mass is call a front

Types of Fronts:

1. Cold Front Types
 - Fast moving pressure wave or squall line
 - cold moving not as violent

2. Warm Front - warm air behind and cold air ahead

3. Stationary Front - moving less that 5

Occlusion
- cold front - fast moving cold front in front of warm front
- warm front -

Cross a Front is discontinuities
- Temperature change
- Shift of wind direction
- Change in wind speed


Weather Hazards

• Fog
• Thunderstorm
• Wind Shear and microburst
• Turbulence

Windshear and Microburst
Microburst
- precipitation drags the air down
- precipitation cool
- horizontal and vertical airspeed
- down draft - 6000'
convective activity
1 miles in diameter ..
spread out near the ground to 2.5"
45 knots in each direction
- Ring of dust
last about 4 mins not more than 15 mins
if encounter microburst - divert to another airport and wait another 15 mins before landing


Thunderstorm
- light momentary change in altitude and or attitude
- light chops

Moderate Turbulence i
Change in altitude and altitude maintain control of the airplane at all times

Sever Turbulence
large and abrupt change in altitude and or attitude
large variation
momentary loose control of the airplane

Extreme  Turbulence
Tossed about practically impossible to control

convective Turbulence  hot air
Bellow puffy air -- it cool down

Mountain wave - lenticular clouds

Clear air turbulence  - not associated with thunderstorm but associate with jet stream
hot air in cecinityu of jet stream


Thunderstorm
- lightning
- Wind shear

Types of Thunderstorms

1. Isolated air mass
2. Frontal thunderstorm
3. squall line thunderstorms

Basic ingredients for a cumulonimbus cloud to form

- lifting force
- unstable air
- moist air (high humidity)

Stages of Thunderstorm

1. Cumulus stage  
1. Continuous updraft
2. Mature stage 
1. Precipitation begins strong updraft
2. Strong down draft
3. Precipitation start to fall
3. Dissipate stage
1. Predominately downdrafts
2. Air current move down and out

Structure Ice
visible moisture
clouds, snow
ice pellets - warmer air at higher altitude, freezing rain

Frost - temperature of collecting surface is or at freezing and the