The solid black lines are the heights. They are close together, or packed, which shows a rapid change in heights over a short distance and thus fast winds. This is the jet stream. One will also notice that the lines run west to east with little change to the north or south. This is considered to be a zonal flow.

The dashed black lines are the vorticity with an "x" to depict the center of maximum vorticity and an "n" to mark the center of minimum voticity. The values of the vorticity, marked by the dashed lines, decrease with distance away from the center of maximum vorticity, marked by the "x".

• 12 hour forecast
  The wave, now positively tilted (oriented from northeast to southwest), is centered in northeast Kansas and has a value of 24. The shortwave extends southwestward from the center through southeast Colorado, northeast New Mexico and into southwest New Mexico.

  24 hour forecast

  The wave is now neutrally tilted (has a north-south alignment) and is centered in southern Missouri. The Maximum value has increased to 26. The trough associated with the shortwave extends through Arkansas to the ArkLaTex region (the border of Texas, Louisiana, and Arkansas). A piece of the trough then extends back to the southwest through Texas, also known as a vort lobe.

  36 hour forecast

  The wave is now negatively titled (aligned from northwest to southeast) as it heads through the Ohio Valley. The maximum value, still 26, is located over the Ohio/Kentucky border. Illinois is for the most part ok as the back edge of the wave is moving out but a forecaster must be aware of other waves. Notice a s/wv (shortwave) in northern South Dakota, with a maximum value of 18 and has vorticity lines wrapped around it. The wave has a nagative tilt as it extends southeastward through Missouri.

  48 hour forecast

  The main shortwave is weakening as it heads into New England. It is very negatively tilted but the value has decreased to 20. The secondary, or next, shortwave is now centered over southern Minnesota/northern Iowa and still has a value of 18. The shortwave trough associated with this vorticity maximum, or vort max, extends through northern Illinois and north central Indiana.

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