MetEd: Meteorology Education and Training. Operated by the COMET Program

Description:
This case exercise looks at a barrier jet event over central and eastern Colorado that took on historic significance in terms of snow amounts and variability in snow distribution. The module emphasizes the mechanisms for producing both very large accumulations and extreme small-scale variability. These mechanisms involved both dynamic and thermodynamic processes in this storm. Model and observed analyses and forecasts are considered in detail as the storm unfolds.

Objectives:
• Analyze a Rocky Mountain Front Range heavy precipitation event to determine the influence of a barrier jet on both precipitation type and amount.
• Forecast critical storm features in a barrier jet case, including winds and precipitation type and intensity.
• Monitor the development of the barrier jet features in the context of the larger-scale forcing.
• Examine the important processes governing the termination of the storm.

Estimated time to complete: 2-3 h

Includes audio: yes

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
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Last published on: 2006-07-27

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Description:
Chapter 6, The Distribution of Moisture and Precipitation, is the second published chapter of the online textbook, Introduction to Tropical Meteorology. Moisture and precipitation distribution governs life in the tropics. Surplus heating and rising motion in the tropics ignites the global water and energy cycles and influences weather in the midlatitudes. Chapter 6 presents the horizontal and vertical distribution of water vapor, tropical cloud formation and distribution, the lifecycle and precipitation characteristics of tropical mesoscale convective systems, and the variability of tropical precipitation on yearly, seasonal, and hourly time-scales. The online textbook has many special features including individual chapter review questions and quiz, topic focus sections, direct access to operational forecasting topics, box sections that elaborate on theoretical concepts, links to resources for further study, critical thinking questions interspersed throughout the text, icons that identify resource links and critical thinking exercises, and science biographies.

Objectives:
At the end of this chapter, you should understand and be able to describe:

* Why water vapor is important to weather and climate in the tropics
* The range and distribution of water vapor content in the tropics
* The distribution of evaporation and evapotranspiration rates in the tropics
* The formation of tropical clouds by convection
* The general pattern of cloud distribution in the tropics
* The typical profiles of potential temperature (Theta) and equivalent potential temperature (Theta-e) in the tropical atmosphere
* How the Saharan Air Layer and other dry intrusions changes the vertical distribution of moisture thermodynamic energy
* The concept of moist and dry static (thermodynamic) energy and its vertical distribution in the tropics
* How the vertical distribution of moist static energy varies with different modes of convection
* The differences between convective and stratiform rain in tropical mesoscale convective systems
* The effects of continental and maritime aerosols on tropical precipitation
* The geographic distribution of annual tropical precipitation and its variability
* The factors that influence the geographic distribution of tropical precipitation
* The seasonal distribution of precipitation in the tropics and unique regional patterns
* The differences between the diurnal cycle of tropical precipitation over land and over ocean, including the influential factors
* Unique characteristics of the diurnal cycle during the equatorial transition seasons (spring and autumn)
* The factors that influence the amount and location of rainfall on yearly and multi-year time scales

You should also be able to identify and describe:

* The factors that influence evaporation and evapotranspiration rates
* The dominant cloud types in the tropics
* The typical zonal and meridional distribution of cloud depth over the tropical oceans

Estimated time to complete: 1.5-2 h

Includes audio: yes

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
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Last published on: 2008-03-19

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Description:
This Webcast features Phil Schumacher, NWS Sioux Falls, South Dakota discussing the conditions that dictate the location of precipitation relative to inverted troughs. Phil presents a composite case study based on collaborative research with Dr. R. Weisman and others, as well as two examples of inverted trough events in the Central Plains. This presentation is based on his presentation at the MSC Winter Weather Course, December 2002, in Boulder, Colorado. The webcast is accompanied by a case exercise, Inverted Trough Case Exercise.

Objectives:
1. Describe inverted troughs and their associated precipitating features.
2. Present the results of a composite inverted trough study, based on the differences between inverted troughs that produce precipitation ahead vs. behind the trough.
3. Demonstrate the use of isentropic techniques in diagnosing important inverted trough features.
4. Look at several case studies demonstrating the impact of inverted troughs on precipitation distributions.

Estimated time to complete: 60 min

Includes audio: yes

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
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Last published on: 2004-01-29

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Description:
This exercise follows the progression of a winter weather event across the Central Plains states beginning 1200 UTC on 7 March 1999. Each forecast question is accompanied by Eta model data and includes a forecast discussion by Phil Schumacher, NWS Sioux Falls, South Dakota. This exercise compliments the Webcast, Inverted Troughs and their Associated Precipitation Regimes, based on a presentation by Phil Schumacher at the MSC Winter Weather Course, December 2002, in Boulder Colorado.

Objectives:
1. Identify whether precipitation will be primarily ahead or behind an inverted by applying the conceptual model of inverted trough precipitation organization.

2. Use isentropic analysis to view the affect inverted troughs have on moisture transport and the implied lift associated with inverted troughs.

3. Use the conceptual model of inverted trough precipitation organization to determine the approximate beginning and ending time for significant precipitation associated with inverted troughs.

Estimated time to complete: 45 min

Includes audio: no

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
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Last published on: 2004-01-29

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Description:
This module provides an introduction to polar-orbiting-satellite-based microwave remote sensing products that depict moisture and precipitation in the atmosphere. The module begins with definitions and descriptions of total precipitable water and cloud liquid water products, contrasting each with more familiar infrared water vapor and window channel products. This is followed by an overview of microwave precipitation estimation and a discussion of how polar-satellite products compare with those from geostationary satellites and ground-based radar. A series of case examples highlights potential weather forecasting applications for total precipitable water and precipitation products. The module also includes an introduction to the Global Precipitation Monitoring Mission to which future NPOESS satellites will be an important contributor. This module takes about 75 minutes to complete.

Objectives:
After completing this module, learners will be able to:
• State the definition of total precipitable water
• State the definition of cloud liquid water
• Describe the difference between window regions and absorption regions of the electromagnetic spectrum
• Describe how precipitation rates are derived over land and ocean
• Describe the goals of the Global Precipitation Monitoring Program
• Interpret total precipitable water, cloud liquid water, and precipitation products presented in case examples

Estimated time to complete: 75 min

Includes audio: yes

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
 * Plug-in information

Last published on: 2006-10-06

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Description:
POES 3: Case Studies contains two short case study examples that demonstrate different uses of polar satellite data. The first case example shows how AMSU microwave data can be used to supplement other datasets to improve precipitation forecasts. The second case example demonstrates the TRaP method for calculating rainfall from Hurricane Georges.

Objectives:
• State the advantages of using microwave data for precipitation forecasting
• Describe the method for comparing NWP forecasts with microwave moisture information
• Compare and contrast the information from GOES water vapor imagery with information from microwave TPW as it relates to Case 1.
• Describe the TRaP product

Estimated time to complete: 1-2 h

Includes audio: no

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
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Last published on: 1999-12-10

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Description:
In this module, Wes Junker, retired Senior Branch Forecaster at NCEP/HPC provides an introduction to Quantitative Precipitation Forecasting, as well as two presentations targeted at QPF issues for the conterminous U.S. (1) east of the Rockies and (2) in and west of the Rockies.

Objectives:
Introduction

1. Recall the three main factors to use when composing a QPF.
2. Explain which meteorological factors affect the quantitative part of QPF.
3. Identify meteorological factors that affect precipitation intensity.
4. Apply pattern recognition skills for anticipating precipitation.
5. Anticipate the influences to QPF from both synoptic and mesoscale processes.
6. Use soundings and the associated instability measures in QPFs.
7. Explain the mechanisms of cell movement and propagation.
8. Identify important impacts on QPF from propagation characteristics.
9. Anticipate how jet dynamics may influence precipitation amount and distribution.
10. Understand some of the unique aspects of tropical systems when composing QPF.

East and West of the Rockies

1. Understand the meteorological processes that occur with the Maddox type events (synoptic, frontal, mesohigh, western types).
2. Recall the climatology of heavy rainfall events for your area.
3. Explain how theta-e is used in forecasting heavy precipitation.
4. Anticipate how terrain impacts heavy precipitation events.
5. Recall the general differences between warm- and cool-season QPF.

Estimated time to complete: 120 min

Includes audio: yes

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
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Last published on: 2007-11-01

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Description:
It is the first streaming video Webcast released by the COMET Program. This interactive and entertaining presentation serves as a helpful reminder of the problems that can plague rain gauge performance including specifics regarding the widely used ASOS rain gauge. The material is suitable for anyone who deploys gauges or routinely uses precipitation gauge data.


A version of this Webcast that can be installed on your computer for local playback is also provided.

Estimated time to complete: 40 min

Includes audio: yes

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
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Last published on: 2001-02-05

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Description:
When the new grid-scale precipitation scheme was implemented in the Eta model on November 27, 2001, precipitation type became available as a forecast variable. This variable can be used to complement the diagnosed precipitation type based on forecasted vertical temperature and moisture profiles. In this case, the diagnosed precipitation type from the NCEP (a.k.a Baldwin/Schichtel) algorithm is compared to the predicted precipitation type in the experimental/parallel version of the 12-km Eta model for an early winter storm in the southern and eastern U.S.

Estimated time to complete: 40 min

Includes audio: no

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
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Last published on: 2003-03-03

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Description:
This brief case study provides maps to compare model-predicted and observed frequency of 24-hour and 48-hour precipitation exceeding various thresholds to serve as a reference of characteristic model behavior.

Estimated time to complete: 1 h

Includes audio: no

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
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Last published on: 2002-01-07

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Description:
This case discusses one occurrence of a well-known problem with the GFS; grid-scale precipitation bombs at T170L42 resolution. Anecdotal evidence suggests that these precipitation bulls'-eyes have been more frequent this warm season, particularly in the central and northern Plains and Midwest. The time-scale, spatial scale, and effect of the GFS precipitation bombs on the forecast are examined. We also discuss whether GFS forecasts that produce such features can be useful to the operational meteorologist.

Estimated time to complete: 1 h

Includes audio: no

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
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Last published on: 2002-11-25

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Description:
This is a brief on an improvement in precipitation forecasts that has, in general, continued to be noticed since the new grid-scale precipitation scheme went into effect when the new Eta-12 became operational on 27 November 2001. One of the elements in the new scheme is the addition of vertical diffusion of cloud water between model layers. The main purpose for this change was to improve erroneous forecasts of warm-season light precipitation in the mid-Atlantic and southeastern U.S. during periods of moist onshore flow, and in the coastal and offshore areas of the West Coast under the marine stratus regime.

Estimated time to complete: 30 min

Includes audio: no

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
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Last published on: 2002-01-16

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Description:
The AVN produces spurious precip "bombs." Now the Eta does too. This case provides a detailed look at Eta model forecast fields leading up to and during an event, including forecast impact and explanation of what's going on inside the model.

Estimated time to complete: 1.5 h

Includes audio: no

Required plug-ins:   Flash RealPlayer Java Adobe® Reader®
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Last published on: 2002-02-26

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