Transcript Wave Cyclone PowerPoint Notes

Mid-Latitude Cyclones
• Low Pressure storm
systems in the midlatitudes
• Starts at a Polar Front –
the boundary at which
cold polar air (cP) meets
the warmer air (mT) of
the mid-latitudes.
• Lasts several days as it
moves across the USA
Stages of a Wave Cyclone
Stage 1:
Stationary Front
Winds move parallel to
front and blow in opposite
directions
H
cP
High Pressure
H
mT
Stage 2 Wave Stage
-The warm air moves north and the
cold air moves south
-Creates a warm front and a cold front
mT
cP
cP
Low pressure forms
the cyclone deepens
or gets more
intense.
L
mT
Stage 3 - Maturity.
A cloud formation in the
cP
shape of a “comma” is
characteristic of a well
developed wave cyclone.
L
mT
Satellite Image
L
Dry Slot
Comma
Cloud
Cold Front
Comma Clouds
Rising and
turning moist
air, illustrated
in the conveyor
belt model,
condenses into
a large commashaped cloud
typical of the
open wave
cyclone.
Figure 13.13
This March
1993 storm
wreaked havoc
along the East
Coast.
Stage 4 - Occlusion
The cold front overtakes the
warm front and lifts the warm
air off the ground.
L
cP
mT
Stage 5 – Dissipating
- Breaks up and forms a stationary front
again
Weather Associated With A Wave Cyclone
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L
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1. Northwest Sector
Usually cold with strong and
gusty winds out of the northwest.
Precipitation light to moderate,
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with heavier precipitation closer
to the low.
If cold enough, the snowfall can
be significant.
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2. Cold Front
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Narrow Band of showers and
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thunderstorms.
Rapid change in wind direction.
Winds increase in speed out of
the W or NW.
Rapid temperature decrease.
Sinking air behind the front often
leads to rapidly clearing skies.
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3. Warm Sector
Usually fair and warm.
Later in the day, showers and
thunderstorms may develop.
Some thunderstorms may be
heavy but most are of the
“garden variety” type.
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4. Warm Front
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Mostly cloudy and cold.
Precipitation often heavy and
occasionally substantial.
Winds often out of the east or
northeast (Nor’Easter).
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L
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