Shear Lines, Fronts and Areas of Confluence/Diffluence Mike Davison HPC International Desks.

Slides:



Advertisements
Similar presentations
What we now know: Difference between weather and climate.
Advertisements

Conceptual Models of Cold Fronts: Anacoldfront Katacoldfront.
Pressure systems, air masses & fronts
Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Chapter 5 Winds and Global Circulation Visualizing Physical Geography.
Thunderstorm Ingredients ©Oklahoma Climatological Survey EarthStorm 2009.
 The main focus is investigating the dynamics resulting in synoptically forced training convective rainfall  Synoptic conditions necessary for the generation.
FACTORS INFLUENCING CLIMATE
HURRICANE DEVELOPMENT What conditions are required? Water temperatures > 26.5°C Convergence of surface winds Upper air divergence Organized mass of thunderstorms.
Kari Murray.  This article is extending on a 10-year climatological study done by Rose et al.  Rose et al. found that tornadoes most commonly occur.
Air Masses of North America
SYNOPTIC CLIMATOLOGY-CH. 7. AIR MASSES.
Weather Maps Isolines- Lines which connect points
Jet Streams.
FACTORS INFLUENCING CLIMATE
Ch. 16: Weather (#1-2).
Basic Convergence and Divergence
MET 10 Lecture 9 Global Winds, Air Masses, and Fronts Chapter 8 & 9 Dr. Craig Clements San Jose State University.
FRONTS Chapter 12. This week onwards Air masses What are fronts Different types of front Weather associated with fronts Mid-latitude Cyclones –Weather.
Concept of Humidity Humidity (absolute humidity) The amount of water vapour in the air (Holding) Capacity of air The maximum amount of water vapour in.
Jet Streams Lessons 25/26 Jet Streams Defined as a narrow ribbon of fast moving air : –1000’s of miles in length, –up to 200 miles wide, –approx.. 2.
Fronts. Definition (Glossary of Meteorology) Front: …generally the interface or transition zone between two air masses of different density Air Mass:
How to get the most from the Internet briefings NWS Boise, Id.
Chapter 8: Air Masses, Fronts Mid-Latitude Cyclones Air Masses  large body of air whose properties of temperature and humidity are fairly similar in any.
WEATHER SYSTEMS WEATHER AND CLIMATE.
1 Lake-Effect Snow (LES). 2 Overview of the Lake-Effect Process n Occurs to the lee of the Great Lakes during the cool season n Polar/arctic air travels.
Major Forms of Condensation. What are the forms of condensation? n Cloud n Fog n Frost and Dew.
The Weather Makers of the Mid-Latitudes
Structure and dynamical characteristics of mid-latitude fronts.
United States Weather Maps. How to Read a Surface Map Surface maps depict the large-scale elements of the weather. These elements include high and low.
Divergence of the Wind We can express the divergence equation in a simplified form, with two terms: Direction Speed The direction and speed terms, in-turn,
Storms. Large scale circulation Movement of air masses Circulation cells Warm air rises, cools then sinks Water vapor decreases air density and warm air.
Planetary Atmospheres, the Environment and Life (ExCos2Y) Topic 6: Wind Chris Parkes Rm 455 Kelvin Building.
FACTORS INFLUENCING CLIMATE The factors that influence climate can be identified by using the following anagram: J. BLOWER J. = Jet Stream B = Bodies of.
From highs to lows and everywhere in between
Canada’s Physical Geography Climate and Weather Part I Unit 2 Chapter 2.
Hurricanes.
Pressure Systems Low pressure: an area where the atmospheric pressure is lower than the surrounding area Air rises then it cools and condenses Weather:
Section 8 Vertical Circulation at Fronts
MET 102 Pacific Climates and Cultures Lecture 15: Air Masses & Fronts MET 102 Pacific Climates and Cultures.
The AtmosphereSection 3 Fronts and Severe Weather 〉 How do fronts affect the weather? 〉 When fronts move through an area, the result is usually precipitation.
Fronts and Air Masses. Air Masses & Fronts Air Mass = large body of air whose temperature and moisture is similar at a given height (can cover thousands.
Air Masses and Fronts METR April Air Mass: a large volume of air that has remained over a surface for a long enough period of time to be.
….A Tricky Business Lesson Objective: Know basic facts and general principles of the elements of weather. Samples of Behavior/Main Points: 1. Identify.
Air Masses and Fronts. Air Mass: – An air mass is a huge body of air that has similar temperature, humidity, and air pressure at any given height. – Air.
Windshear.
Air Masses and Fronts D 68-73
Class #26: Friday October 30 Thunderstorms 1Class #26: Friday, October 30, 2009.
Clear Air Turbulence.
FACTORS INFLUENCING CLIMATE
EASC 11 Forecasting, Weather Maps, and Severe Storms Forecasting
The Study of the Weather and Climate
Chapter 16 Earth Science WEATHER.
Mid-Latitude Cyclone Development
Air Masses Air masses are large bodies of air where temperature and moisture content are constant throughout. Moisture content and temperature of a mass.
By: Mike Vuotto and Jake Mulholland
The Jet Stream … and its associated upper-air features
High and Low Pressure Systems
Air Circulation Jeopardy
Air Mass: An air mass is a huge body of air that has similar temperature, humidity, and air pressure at any given height. Air masses are classified by.
Air Mass: A huge body of air that has similar temperature, humidity, and air pressure at any given height. Classified by 2 characteristics: Temperature.
WEATHER SYSTEMS WEATHER AND CLIMATE.
Air Mass: An air mass is a huge body of air that has similar temperature, humidity, and air pressure at any given height. Air masses are classified by.
Air Masses Air masses are large bodies of air where temperature and moisture content are constant throughout. Moisture content and temperature of a mass.
Cold fronts, Warm fronts, Stationary fronts and Occluded fronts.
Cold fronts, Warm fronts, Stationary fronts and Occluded fronts.
Cold fronts, Warm fronts, Stationary fronts and Occluded fronts.
Air Masses and Fronts.
Latitude What is Latitude? Lines of Latitude run horizontally
Air Masses Air masses are large bodies of air where temperature and moisture content are constant throughout. Moisture content and temperature of a mass.
Presentation transcript:

Shear Lines, Fronts and Areas of Confluence/Diffluence Mike Davison HPC International Desks

Shearlines vs. Fronts Shear Lines: are associated with wind shifts (direction and speed). –A line or narrow zone across which there is an abrupt change in the horizontal wind component parallel to this line A line of maximum horizontal wind shear. An area of directional wind confluence along the tail end of a surface front. Lacks the baroclinicity/density discontinuity of surface fronts Fronts: The interface or transition zone between two air masses of different density. –Density depends on temperature and moisture content –Fronts either lie along shear lines or can lag behind them.

Wind Confluence and Diffluence in the Caribbean

Wind Confluence and Diffluence in South America

Wind Divergence

Divergence of the Wind We can express the divergence equation in a simplified form, with two terms: Direction Speed The direction and speed terms, in-turn, can be expressed as directional/speed diffluence and confluence –Confluence is not equal to Convergence –Diffluence is not equal to Divergence

Divergence (Cont) Divergence/convergence calculations need to take into account the direction and speed terms. –This is done through objective analysis Streamline analysis is a subjective technique, and it only shows directional diffluence and confluence. –It does not show convergence/divergence

Example Directional Diffluence/Confluence Directional ConfluenceDirectional Diffluence

Speed Diffluence/Confluence Speed Diffluence Speed Confluence A B

Convergent or Divergent? A Directional Confluence Speed Diffluence

Convergent or Divergent?

A Directional Diffluence Speed Confluence

Convergent or Divergent?

Evaluation of Shear Lines

Front/Shear Line Evaluation

Front and Shear Line

Forecast Hints During the Winter Months –Convective activity over the Gulf of Mexico and gulf coast of Mexico tends to be capped below 500 hPa (20,000 ft) Evaluate upper dynamics for CONVERGENCE or DIVERGENCE before forecasting thunderstorms. –If models forecast post frontal northerlies of 25Kt or greater, and dew point temperature of 20C (68F) or greater over southern Mexico. Forecast 12 hrs rainfall accumulation of at least 2-4 inches.

Example of “Ideal” Conditions for Heavy Rainfall

Example Front/Shear Line Caribbean

Example Front/Shear Line South America

Identify Features

Satellite Interpretation

Analysis