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New SPC convective outlook categories

Posted by Scott Dennstaedt 
New SPC convective outlook categories
October 27, 2014 09:16AM
The Storm Prediction Center (SPC) has expanded the risk categories from four to five and clarified the risk previously labeled as "See Text". That descriptor is replaced by a categorical line and the term "Marginal" to denote areas with a 5 percent probability of severe weather. The upper end of the "Slight Risk" category is renamed "Enhanced" (short for "Enhanced Slight") to denote a threshold 30 percent probability of severe wind or hail and/or a 10 percent chance of a tornado during the Day 1 period. For Days 2 and 3, the "Enhanced" risk category denotes a 30 percent total severe probability. The Moderate and High risk thresholds will remain essentially unchanged.

Current:

1. See Text
2. Slight (SLGT)
3. Moderate (MDT)
4. High (HIGH)

New:

1. Marginal (MRGL) - replaces the previous SEE TEXT and now is described with Categorical line on the SPC Outlook.
2. Slight (SLGT)
3. Enhanced (ENH) - replaces upper-end SLGT risk probabilities, but is not a MDT risk
4. Moderate (MDT)
5. High (HIGH)

An example of the graphic is shown below.


http://www.spc.noaa.gov/exper/dy1-3example/day1-20110601-1300.gif

Scott Dennstaedt
CFI & former NWS meteorologist
Administrator of AvWxWorkshops.com
Most pilots are weatherwise, but some are otherwise™



Edited 2 time(s). Last edit at 10/27/2014 09:20AM by Scott Dennstaedt.