Skip navigation

• VISIT Home
• Training Sessions
• Training Calendar
• Blog Sites
• VISIT Satellite Chat
• The VISIT Program
• VISIT People
• VISIT FAQ
• Links / Tutorials
• RAMSDIS Online
• VISIT Training DVD

TROWAL Identification

Scott Lindstrom, Scott Bachmeier, Jon Martin

Introduction

TROWAL stands for TROugh of Warm air ALoft

Objectives:

1. Learn more about extratropical cyclone structure
2. Learn how to use AWIPS to find TROWALs
3. Can TROWAL identification help forecast accuracy?

Outline:

1. Review conceptual models of cyclone airflow
2. Review vertical motion
3. Historical review of TROWALs
4. Characteristics of TROWALs
5. How to find TROWALs
6. Case study

Prerequisites

This is a basic course. There are no prerequisites.

If you have not taken the VISIT Cyclogenesis session, it is recommended that you either signup for the Cyclogenesis teletraining OR go through the audio version before taking the TROWAL session.

Training Session Options

LMS students - to begin the training, use the web-based video or audio playback options below (if present for this session).

1. Web-based video that can be taken at anytime (streamed, not recommended for low-bandwidth users). Be sure to have your speakers on and the volume loud enough to hear the presentation. For students who initiated this course in the NWS Learning Center (LMS), certificates of completion can be obtained from the learning center's "My Transcript" page upon completion of the associated quiz.

2. Audio playback (recommended for low-bandwidth users) - This is an audio playback version in the form of a downloadable VISITview and can be taken at anytime. Certificates of completion for NOAA employees can be obtained on the E-Learning Management System LMS

   Create a directory to download the audio playback file (92 MB) from the following link: http://rammb.cira.colostate.edu/training/visit/training_sessions/trowal_identification/trowal_identification_audio.zip

   After extracting the files into that directory click on either the visitplay.bat or visitauto.bat file to start the lesson. If both files are present, use visitauto.bat

3. Live VISIT teletraining (with an instructor leading the session). Check the VISIT Training Calendar to signup for teletraining. The session will last 75 minutes. This teletraining session uses the VISITview software, where a Windows PC with an Internet connection is needed.

   Please follow the teletraining installation instructions to install the session

References/Additional Links

• Talking points are available for this lesson and may be printed out to easily review the session in detail at any time.
• Crocker, A. M., W. L. Godson, and C. M. Penner, 1947: Frontal Contour Charts. J. Meteor., Vol. 4, 95-99.
• Godson, W. L., 1951: Synoptic properties of frontal surfaces. Quart. J. Roy. Meteor. Soc., Vol. 77, 633-653.
• Penner, C. M., 1955: A three-front model for synoptic analyses. Quart. J. Roy. Meteor. Soc., Vol. 81, 89-91.
• Martin, J. E., 1998a: The structure and evolution of a continental winter cyclone. Part I: Frontal structure and the occlusion process. Mon. Wea. Rev., Vol. 126, 303-328.
• Martin, J. E., 1998b: The structure and evolution of a continental winter cyclone. Part II: Frontal forcing of an extreme snow event. Mon. Wea. Rev., Vol. 126, 329-348.
• Martin, J. E., 1999: Quasigeostrophic forcing of ascent in the occluded sector of cyclones and the TROWAL airstream. Mon. Wea. Rev., Vol. 127, 70-88.

Content Developed

• Developed: 2002
• Updated: 2005

Information Contact

• Scott Lindstrom (608) 263-4425
• Scott Bachmeier (608) 263-3958