The Winter Weather Events
of January 3-5, 2005

Answer to Question 6
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6. Examine a movie from 4:00 am to noon on Tuesday Jan 4th, with BREF1 from Vance AFB (KVNX), Mesonet air temperatures and Mesonet wind observations.

  • What precip type is suggested by the radar echoes?
  • Where is the freezing line, in relation to the precip observed by the Vance radar?
  • What is happening to the Mesonet's wind observations north and west of the freezing line? Why is this?



Answer.

  • The reflectivity patterns still show the mottled, cellular characteristics of liquid preipitation
  • Much of the precipitation is falling to the north/cold side of the Mesonet-indicated 32F freezing line (in blue).
  • In much of this sub-freezing precipitation area, the Mesonet wind barbs are missing. They have been reduced to zero by ice accumulation.

The Bottom Line:

  • Mesonet wind observations are often your first clue (other than spotter reports) of ice accumulations on elevated structures.
    • They are 10 meters (33 feet) off the ground


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