Developing the Ozarks pulse thunderstorm index

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Sunday, 17 January 2010
Exhibit Hall B2 (GWCC)
Doug Thomas Cramer, NOAA/NWSFO, Springfield, MO; and N. A. Lock

Handout (658.5 kB)

Pulse-type thunderstorms generally occur in environments with weak vertical wind shear and limited forcing, and they present a forecast challenge because of their seemingly random nature. They also present a warning challenge because most cells do not produce severe weather, and those that produce severe weather do so only briefly. The Ozarks Pulse Thunderstorm Index (OPTI) was created at the National Weather Service office in Springfield, MO in an attempt to better predict the potential for pulse-type thunderstorms. The index uses four parameters to do this - lowest 100 mb mixed layer CAPE and CIN, precipitable water, and 700-350 mb mean relative humidity. Data for the project was from July and August of 1996-2008 and includes observed sounding from Springfield, MO (KSGF), North American Regional Reanalysis (NARR) data and storm reports from NCDC. In limited initial testing this summer, the OPTI showed some skill, although additional work is ongoing to further refine it.