Under the Anvil

Scattered thunderstorms moved across northeastern Iowa this evening. The following photos were taken under the back side of an anvil as it passed over Cedar Falls, Iowa. It was a small cell that produced only a trace of rain here. Stronger storms associated with severe thunderstorm warnings occurred to our northeast and southwest. The following photos show clouds that formed under the anvil. 

 Altocumulus castellanus under the anvil slowly being revealed as light rain moves southeast away from the camera. Photo looking East.  Photo by Craig Johnson, copyright 2018.

Altocumulus castellanus under the anvil slowly being revealed as light rain moves southeast away from the camera. Photo looking East.  Photo by Craig Johnson, copyright 2018.

 Altocumulus wave type clouds under the thunderstorm anvil. Photo looking SE. Photo by Craig Johnson. Copyright 2018.

Altocumulus wave type clouds under the thunderstorm anvil. Photo looking SE. Photo by Craig Johnson. Copyright 2018.

 Mammatus clouds under the back of the anvil - looking W. Photo by Craig Johnson, copyright 2018.

Mammatus clouds under the back of the anvil - looking W. Photo by Craig Johnson, copyright 2018.

 Surface weather map at 1900 CDT 5-25-2018 (0Z 5-26-2018). A Weak low pressure trof over north Central  Iowa helped trigger thunderstorms over northeast Iowa into Minnesota and Wisconsin. Servere weather was reported with some of the storms. The map shows surface temperatures in the middle 80s ahead of the trof with dew points in the mid to upper 60s. The analysis shows the Theta-e field. Theta-e measures the total heat available in the atmosphere. It takes into account air temperature plus the heat that would be available if water vapor in the air condensed and released its heat (latent heat).The higher the theta-e temperature (in degrees K) the more available heat).    

Surface weather map at 1900 CDT 5-25-2018 (0Z 5-26-2018).
A Weak low pressure trof over north Central  Iowa helped trigger thunderstorms over northeast Iowa into Minnesota and Wisconsin. Servere weather was reported with some of the storms. The map shows surface temperatures in the middle 80s ahead of the trof with dew points in the mid to upper 60s. The analysis shows the Theta-e field. Theta-e measures the total heat available in the atmosphere. It takes into account air temperature plus the heat that would be available if water vapor in the air condensed and released its heat (latent heat).The higher the theta-e temperature (in degrees K) the more available heat).