ATM OCN (Meteorology) 100
MIDLATITUDE WEATHER SYSTEMS
PART I: THE SETTING, AIR MASSES & FRONTS
Summer 2004
Lecture #19 Scheduled for:
19 JUL 2004 (M)
Recommended Readings from Moran (2002):
pages 221-229; 189-190.
Today's Lecture Objectives:
- To discuss the basis of air mass classification and to differentiate among the various major air mass types.
- To list two criteria that an air mass source region must meet.
- To identify the various air masses that regularly form over or invade North America and discuss the typical weather conditions associated with these air masses.
- To describe the processes that contribute to air mass modification, identifying those conditions that determine the degree of air mass modification .
- To list at least two criteria involved with the analysis of a front on a surface weather map.
- To identify the conditions needed for frontogenesis and frontolysis.
- To compare and contrast warm fronts, cold fronts, stationary and occluded fronts in terms of their structure and associated weather.
Outline:
A. SCOPE OF MIDLATITUDES
- Geographic Extent
- Human Aspect
- Meteorological Significance of Midlatitudes
B. AIR MASSES
- Definition
- Historical Perspective
- Air Mass Considerations
- Air Mass Characteristics
- Dimensions
- Life History
- Requirements For Air Mass Generation
- Traditional Air Mass Classification Scheme & Analysis
- Primary Air Mass Types
- Air Mass Generation Mechanisms
- Air Mass Modification
- Air Masses Over North America
C. FRONTS or FRONTAL ZONES
- Introduction
- Principal Global Frontal Zones
- Types of Synoptic Scale Fronts
- Cold Fronts
- Warm Fronts
- Stationary Fronts
- Occluded Fronts
- Frontal Analysis on Weather Maps
- Temperature Gradients
- Dewpoint Gradients
- Wind Shifts
- Pressure Patterns
- Characteristic Cloud Patterns
- Vertical Structure of a Frontal Surface
- Cold Fronts
- Warm Fronts
- Stationary Fronts
- Occluded Fronts
- Temporal Evolution of Fronts
- Frontogenesis
- Frontolysis
Unit continues as Midlatitude Weather Systems: The Extratropical Cyclone
Links to Other References:
The Air masses and fronts module from Weather World 2010 (Univ. of Illinois-Urbana-Champaign).
Latest revision: 3 August 2004 (0400 UTC)
Produced by Edward J. Hopkins, Ph.D.
Department of Atmospheric and Oceanic Sciences
University of Wisconsin-Madison Madison, WI 53706
hopkins@meteor.wisc.edu
URL: aos100/lectures/s0419xtr1.html