Fundamentals of Mesoscale Weather Forecasting

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Quick Facts about METEO 361

METEO 361 is one in a series of four online courses in the Certificate of Achievement in Weather Forecasting program. It is offered every Spring (January - May) semester and periodically in the Summer (May - August) semester.

Prerequisites: METEO 101
METEO 361 is designed specifically for adult students seeking a Certificate of Achievement in Weather Forecasting.  The course will build off of general atmospheric principles covered in METEO 101 in order to draw connections between large-scale (synoptic) weather patterns and smaller-scale (mesoscale) weather.  While many topics in METEO 361 relate to the development, evolution, and prediction of various types of deep, moist convection, other topics such as winter mesoscale weather and fire weather are also covered.

Photograph of a supercell thunderstorm.
A supercell thunderstorm in the Black Hills of South Dakota in July, 2009, which later produced a funnel cloud and large hail.
Credit:  David Babb

Why learn about mesoscale forecasting?

Initially, you might not be familiar with the term "mesoscale," but I assure you that mesoscale weather features impact everyone.  Mesoscale weather features are those that are "medium"-sized -- smaller than the synoptic-scale features covered in METEO 101, but larger than very small features only spanning a few kilometers.  Therefore, thunderstorms, lake-effect snow, terrain-induced wind circulations, and sea / lake breezes all fall under the umbrella of mesoscale meteorology.  So, whether you live near the beach, in the mountains, or anywhere that thunder occasionally roars, mesoscale meteorology is part of your life!

Furthermore, many types of dangerous and destructive weather occur on the mesoscale.  Thunderstorms can spawn destructive hail, damaging wind gusts, flooding rains, and even tornadoes.  These phenomena can be a threat to both life and property, and understanding mesoscale meteorology is critical to making accurate short-term weather forecasts and assessing potentially life-threatening risks.

What will you learn in this course?

Your journey through mesoscale forecasting will begin by defining the mesoscale and drawing comparisons and contrasts with the large-scale weather systems you studied in METEO 101.  Indeed, a sound knowledge of synoptic-scale weather systems is critical in making mesoscale weather forecasts, and you'll explore the connection early in the course.  You'll learn about a variety of mesoscale forecasting tools, take an in-depth look at skew-T / log-p diagrams, and develop conceptual models of a wide variety of mesoscale weather phenomena.  While many of the topics covered in METEO 361 relate to the development, evolution, and prediction of deep, moist convection, you'll also learn about other various topics, as the course outline below demonstrates.

Lesson 1:  Meeting the Mesoscale (defining and sub-dividing the mesoscale, Lagrangian time scales versus durations, convection-allowing computer guidance)

Lesson 2:  Tools for Mesoscale Forecasting and Analysis (applications of satellite imagery, the importance of the big-picture pattern, introduction to Convective Available Potential Energy, vertical lapse rates, vertical wind shear, wind profilers, radar reflectivity and nowcasting, applications of Doppler and dual polarization radar)

Lesson 3:  Sizing Up the Synoptic Scale (The Big Picture at 500 mb, synoptic-scale surface boundaries, lee troughs, pre-frontal troughs and confluence, the big picture at 850 mb, elevated convection, upper-level jet streaks, coupled jet streams)

Lesson 4:  Advanced Tools for Assessing Deep, Moist Convection (more on Convective Available Potential Energy, potential temperature, mixing ratio, the lifting-condensation level, mixed-layer Convective Available Potential Energy and convective inhibition, capping inversions, most-unstable Convective Available Potential Energy, equivalent potential temperature, convective stability indices, hodographs, convective temperature, forecast soundings)

Lesson 5:  Discrete and Semi-Discrete Thunderstorms (conceptual models, structure and life-cycle of single-cell, multicell, and supercell thunderstorms)

Lesson 6:  Organized Convective Systems (nocturnal low-level jets, mesoscale convective systems and complexes, squall lines, frontogenesis, lake-effect snow and thundersnow)

Lesson 7:  Mesoscale Air-Mass Boundaries (dry-line climatology and structure, dry-line bulges, outflow boundaries, sea / lake breeze fronts)

Lesson 8:  Terrain Effects (differential heating, mountain-valley circulations, high-level heat sources, fire weather, urban heat islands, cold-air damming)

Lesson 9:  A Closer Look at Supercells (high-precipitation, classic, and low-precipitation supercells, structure of supercells, bulk vertical wind shear and long-lived supercells, mesocyclogenesis and storm-relative helicity, supercell motion, splitting supercells)

Lesson 10:  Storm Hazards (lightning, hail, downbursts, bow echoes, derechos, non-supercellular tornadoes, pattern recognition and forecasting of flash floods)

How does this course work?

Much like METEO 101, all course materials are presented online. The course lessons include many animations and interactive tools to provide a tactile, visual component to your learning. Your instructor will assess your progress through online quizzes, lab exercises, and projects, all of which focus on your ability to analyze key observational and forecast information regarding current or past mesoscale weather events. While deadlines in this course may not occur every week, you should expect to spend 8 to 10 hours per week studying the lesson material and completing assignments to stay on pace. Assignment deadlines generally occur every few weeks.