Examining the Counterclockwise Turning of Surface Hodographs in the Southern Plains

Observations by Bluestein and numerical simulations by Rotunno showed a counterclockwise turning in the surface hodographs during the on-set of low level jet episodes. Bluestein used observations from the Oklahoma and Texas mesonets, Doppler wind profiles, and numerical forecasts to see if there was a counterclockwise turning in the southern region of the Great Plains. After averaging the data, to remove any disturbances that could alter the data, he found that there was a counterclockwise turning on surface hodographs. Rotunno looked at model simulations at the surface to see if it would replicate the counterclockwise turning of surface hodographs by Bluestein. The results from the model simulations also showed a counterclockwise turning of surface hodographs in the great plains which differs from the clockwise turning hodographs above the surface. Rotunno also goes into detail about why the counterclockwise turning occurs on surface hodographs.

This poster will talk about the attempts to replicate these papers using observation data gathered during the Plains Elevated Convection at Night (PECAN) campaign event during the summer of 2015. The surface observations were taken from NCAR sites at Minden, Nebraska, Ellis, Kansas, and Brewster, Kansas. Hodographs at heights above the surface were also created using data from PECAN to show the clockwise turning as heights increase. The MetPY Python module was used in order to create these hodographs.