Wednesday, May 7, 2008

Multi-cell Storm Tower Complex, Northern Permian Basin and Supercell, South-Central Permian Basin, May 6th, 2008


















Convection began as early as 2030Z in the western sector of the region. The atmosphere was very unstable, comparable to the day before, but effective bulk shear was forecast to be higher later in the afternoon as an Upper Level Closed Low moved east from northwestern Mexico with accompanying height falls and acceleration of the Low Level Jet. Leaving Midland at around 2100Z, a decision was made to target developing convection in Winkler county with movement to the northeast. The first image, above, is from a radar capture while in transit on SH 18 at 2145Z showing warned county, Andrews, of severe storm with hail. The following digital image is taken from SH 181, looking north at warned storm tower, on right, and tailing back-building convection, to left. The next image is a closer view of warned storm in central Andrews county showing rain and hail core shaft.





A decision was made to turn around and target what appeared to be a developing SuperCell located near the Pecos River near the intersection of Ward, Pecos, and Crane Counties, near the town-site of Grandfalls, Texas, where the author was present the previous day (should have waited). While driving back to the south the author captured the following image of a collapsing updraft, possibly hail dominate, west of Odessa. The subsequent image is of radar capture of this storm tower which had developed on the northwestern side of the complex with the associated embedded developing SuperCell structure. From this radar capture the intensifying reflectivity can be noted at the bottom of image. The cell vectors, pointing northeast as indicators of both direction and speed would veer toward the east shortly after this time of approximately 2220Z as rotation became persistent. The rotating cell became tornado warned by MAF/NWS. The author proceeded south and east along FM 1788 and 1787 until intersecting SH 349 toward Rankin. It was hoped that imaging could be taken from the southeast side of the advancing storm in order to capture rotation of updraft. The next image was taken from SH 349 approximately 5 miles south of the Midland County line at 2315Z, looking southwest at inflow band and lowered updraft circulation center, followed by zoom of same. The movement of storm was a little south of toward the author. It appeared that the storm was beginning to "gust out". The next image was taken after driving further south into Upton County, approximately 11 miles south of Midland County line, and looking west at collapsing updraft and associated Arcus Cloud development as a result, 2345Z.



The last image, below, is a visble satellite capture at 2245Z of the two areas that were "ground"ob-served. The northern complex of muti-celled towers is noted, Andrews, Gaines, and Dawson counties and the southern supercell structure near the Pecos river is also shown.


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