Weather I Ch. 3

Front 1

Airmass?

Back 1

• Airmass: Large body of air that as essentially uniform temp and moisture conditions in a horizontal plane

Front 2

Stability of air masses?

Back 2

• Warm stable, cold unstable

Front 3

Air mass classifications

Back 3

• Airmass classification: named according to their moisture content, location, and temperature (in relation to the ground beneath it):
Maritime/Continental

Front 4

Maritime and Continental air masses

Back 4

o Maritime: Moist. Can become Continental via precipitation over land
o Continental: Dry. Can become Maritime via evaporation over body of water

Front 5

Front?

Back 5

• Front is in a trough of low pressure
• Pressure falls, then rises as front passes

Front 6

Frontal Discontinuities?

Back 6

• Frontal Discontinuities (TD’s Win Playoffs)
o Temp: Front is named after temp change
o Dew point: Used to determine airmass boundary.
o Wind Shift: at least 90*
o Pressure Change: Pressure falls, then rises as front passes

Front 7

Factors influencing frontal weather?

Back 7

o Moisture Content
o Contrast in Temp/Moisture
o Stability of air mass
o Slope of front
o Speed of front

Front 8

Cold Fronts?

Back 8

• Cold Fronts: Unstable, cumuliform, showery, clear icing, good visibility
o Movement: SE at 20kts
o Wind Shift: SW to NW

Front 9

Warm Fronts?

Back 9

• Warm Fronts: Stable, weather occurs ahead of surface front, steady precip and reduced visibility ahead of frontal passage, stratiform clouds
o Movement: NE at 15kts
o Wind Shift: SE to SW

Front 10

Squall lines?

Back 10

• Squall Lines: Thunderstorms ahead of fast moving cold fronts, hazard to aviation. Can form 50-300 miles ahead of front

Front 11

Stationary Fronts?

Back 11

• Stationary Fronts: similar to warm fronts, 180* wind shift, can be aligned in any direction

Front 12

Occluded Fronts?

Back 12

o Movement: NE at speed of front in contact with the ground
o Wind Shift: SE to NW