a) moisture content of the warm air mass (moisture necessary for clouds)
b) stability of the warm air mass
c) speed and steepness of the cold frontal surface
3. Recognition in flight
a) line of heap type clouds (due to frontal lift)
b) deck of clouds may pracede front
c) even if there is no cloud, there will be turbulence, a wind shift and a temperature change during a FROPA (FROntal PAssag)
4. Flight problems
a) wind shift
- always requres correction to the right
- most significant in the lower levels
b) ceiling and visibility
- low ceiling and viaibility a band up to 50 miles wide at the front
- a slow moving front has a larger area of bad weather
- visibility improves in cold air behind front
c) turbulence
- strong in the vicinity of an active front
- thunderstorm in the summer are the greatest threat to flight
- severe weather more likely with a cold front
- squall line can precede a cold front
d) precipitation band is rarrow
e) icing may be severa in clouds of vertical development
B. Warm Front
1. Structure
2. Factors affecting the Weather
a) moisture content of the warm air
b) stability of the warm air
c) degree of overrunning of the warm air
3. Recognition in Flight
a) thickness of cloud deck increases at front
b) temperature change and wind shift
c) cloud base lower at front
4. Flight Problem
a) wind shift - always requires alteration to the right
b) ceiling and visibility
- large area of low cloud and low visibility 200 miles or more ahead of the front
- low clouds form in the precipitation ahead of front cold aire
c) occasional turbulence may be fount
d) precipitation and icing
- intensity of pcpn(Preciotitation) increases in vicivity of front
- possible icing in pcpn in cold air
- wet snow is a problem, not dry snow
- ice pellets indicate freezing rain aloft
- icing in cold air cloud is usually not serious because of low moisture content
- icing in warm air serious in heap type cloud
- heavy icing likely with freezing rain (temperature below freezing near the fround, above freezing aloft)
note:
Freezinf Rain - only with warm front or TROWAL
Freezinf Drizzle - only with Stratus cloud
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