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 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 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 - - described according to air mass which is approaching and relative motion

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 Fronts (2:2)

Sectors in mid-latitude cyclonic storms

Air sectors and air flow associated with a mid-latitude cyclonic storm from map view and 3D view

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 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 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! Case study 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