Transcript Chapter 7- Synoptic Climatology

Chapter 7- Synoptic climatology
Instantaneous climatological conditions
•a snap shot of what the climate is like at
some point in time
Typically used in meteorological forecasting to
show current weather conditions
Synoptic- Of or relating to meteorological
or climatological data obtained nearly
simultaneously over a relatively large area
of the atmosphere.
Air mass
locations,
designations
and tracks
Mid latitude cyclonic storm tracks
Cyclogenesis in
the mid-latitudes
Cyclonic storms
• Associated with Low pressure systems
• Lows moved by Upper level high velocity winds
- Jetstream
• usually involve air masses with different properties
- one warm the other cold
- one humid the other dry
Cyclone (L)-Anticyclone (H) relationships to Upper
Air flow and vertical motion
Fronts (1:2)
• Transition zone between air masses
- described according to air mass which is
approaching and relative motion
• Cold Front (can move very fast)
- colder air mass moving faster than warmer air
- lifts warm air up in front of it
- may form something called a "dry line"
> associated with strong thunderstorm development
Fronts (2:2)
• Warm Front (typically moves more slowly)
- warmer air mass moving faster than cooler air
- warm air rides up over cold dense air
- usually a wider band of "active" weather
Sectors in mid-latitude cyclonic storms
Air sectors and
air flow
associated with
a mid-latitude
cyclonic storm
from map view
and 3D view
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Factors influencing mid latitude cyclones
blocking highs- High pressure systems
that do not move force other weather
producing features like MLCS to be
deflected around them or to stack up behind
them
persistent jetstream patterns- these
force MLCS to track over the same region
over and over
Case study- 1993 flooding in upper mid-West
Jetstream track was across the north central US
Multiple Mid-latitude Cyclones came through the
upper midwest one right after another
Rossby waves in the Jetstream stood still, were not
present, or were timed to coincide exactly with
making the storms track across the upper midwest
Resulted in tremendous amounts of rainfall
Some locations received 250% of their annual
precipitation in 4 months!
Synoptic set up of 1993 floods