21st Conf. on Severe Local Storms and 19th Conf. on Weather Analysis and Forecasting/15th Conf. on Numerical Weather Prediction

Wednesday, 14 August 2002
Dramatically improving warning services—one office's experience
Stephen S. Parker, NOAA/NWS, Morristown, TN; and H. Waldron
Poster PDF (42.2 kB)
The Morristown, TN WFO, which serves East Tennessee, Southwest Virginia, and extreme Southwest North Carolina, has shown dramatic improvement and sustained excellence in the issuance of severe thunderstorm, tornado and flash flood warnings over the past three years (see Tbl 1). (my apologies on the table format.)

Tbl1 / 1998/ 1999/ 2000/ 2001

CSI_ / 35.8 / 69.3 / 75.1 / 79.7

POD_ / 85.7 / 89.4 / 93.2 / 92.9

FAR_ / 62.0 / 24.6 / 20.6 / 15.2

CSI (Critical Skill Index) and POD (Percentage of Detection) have increased substantially, and FAR (False Alarm Rate) has decreased even more impressively. FAR is only one-quarter what it was in 1998. CSI has more than doubled over a four-year period. In that time, our "ranking" has risen from "off the charts" in 1998, to 6th in the country in 1999, to 4th in 2000, and then 3rd in 2001. This office has had the highest CSI in the Southern Region of the National Weather Service each of the past three years. From another perspective, office CSI was 11.4% below the national average in 1998, but finished 25.3% above the national average in 2001. Our current numbers far exceed regional and national goals.

Flash flood warnings showed even larger numerical gains during this period (see Tbl 2).

Tbl2 / 1998/ 1999/ 2000/ 2001

CSI_ / _7.2 / 17.0 / 52.6 / 66.4

POD_ / 87.5 / 31.0 / 93.8 / 94.6

FAR_ / 92.7 / 72.5 / 45.5 / 31.0

The CSI has increased by a factor of nine over a four-year period. At the same time, the FAR has decreased by over 60%. Again, the 2001 numbers far exceed regional and national goals.

These remarkable improvements resulted largely from the following: - intelligent and aggressive use of science and training for issuing warnings; - an internal/external evaluation program for all warning-related activities; - increased verification efforts; and - increased teamwork among all office personnel.

These four factors will be discussed in detail and suggestions will be presented for how other offices can make use of this information. Many of the concepts we applied are well-known. However, the importance of applying those concepts, and the benefits to be reaped, need to be emphasized.

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