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Regional and Mesoscale Meteorology Branch

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TROWAL Identification


Scott Lindstrom

Scott Bachmeier

Jon Martin



Winter / Sat





Last Updated:



TROWAL stands for TROugh of Warm air ALoft


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


  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

Training Session Options

NOAA/NWS students – to begin the training, use the web-based videoYouTube video, or audio playback options below (if present for this session). Certificates of completion for NOAA/NWS employees can be obtained by accessing the session via the Commerce Learning Center.

  1. Live VISIT teletraining session led by an instructor (30 minutes). Check the VISIT Training Calendar to see the current schedule and sign up. Upon registering for a teletraining session, you will receive an email with a link (GoToMeeting or WebEx) to connect to the session.

  2. YouTube video:


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.
This course is Basic

It is recommended that you take the VISIT Cyclogenesis session before taking the TROWAL session.


Scott Lindstrom

Page Contact

Bernie Connell


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