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Posted at 08:02 AM ET, 12/13/2012

The Weather Channel introduces index for rating winter storms

First it gave them names, now it’s assigning them numbers. In its continued aggressive push to help viewers identify and understand storms, the Weather Channel has unveiled a new numeric system for rating the impact of winter storms.

The system is called STORM:CON, serving as a companion to its TOR:CON index which communicates tornado potential. Cities in the path of a winter storm will be assigned a number on a 1-10 scale based on a storm’s disruptive potential.

The scale is broken down into these 5 number groupings according to the Weather Channel:

* (10) – Reserved for anticipation of extreme events that completely shut down travel and commerce for several days.
* (8-9) – Impacts that shut down commerce and travel for one or more days, typically reserved for significant storms that occur three to four times a year.
* (6-7) – Impacts that interrupt commerce or travel for a day or less. National Weather Service winter storm warnings for a major metro area would fit into this category. Examples are recently named winter storms Athena, Brutus and Caesar.
* (4-5) – Impacts that disrupt commerce or travel, but not force closures.
* (1-3) – Snow or ice will occur, but will not have widespread impacts.

A computer algorithm will spit out preliminary STORM:CON numbers twice daily based on snow, wind and ice potential. TWC meteorologists will then tweak these numbers according to the following subjective criteria:

* duration of the storm
* time of day [the storm is hitting]
* day of the week [the storm is hiting]
* how close in time to a previous significant winter event it occurs
* whether the storm occurs early or late in the season

“With STORM:CON, The Weather Channel is using its meteorological information and data, resources and technology to bring a more systematic approach to the way we communicate with consumers during severe winter weather,” said Tom Niziol, winter weather expert for The Weather Channel.

Prior to STORM:CON, there was no national operational winter storm scale for rating storms prior to impact. NOAA currently uses two scales for rating winter storms after they have struck: 1) The Northeast Snowfall Impact Scale (NESIS) 2) The Regional Snowfall Index (RSI)

Although I had (and continue to have) reservations about the Weather Channel’s storm naming scheme, I see some practical value in this sort of scale for expressing the potential impacts of a winter storm at the local level. It’s simple and can potentially give people a quick sense of how significantly a storm may affect their lives. We’ve developed scales like this at the Capital Weather Gang and used them for many years.

My one concern about the Weather Channel’s effort is whether it can effectively do this for every major city. Can its meteorologists headquartered in Atlanta have the local knowledge to understand what characteristics of different cities make them more or less vulnerable to different kinds of winter weather events?

Ryan Hanrahan, a broadcast meteorologist in Connecticut, expressed another potential shortcoming on Twitter: “Numbers are fine but I’d rather spend the time discussing specific impacts not what a number means,” Hanrahan said.

Nate Johnson, a broadcast meteorologist in Raleigh, tweeted a similar view: “Any time you reduce a complex entity to a single number, you discard important information. (See: Saffir-Simpson Scale)”

Others concerns voiced on Twitter focused on The Weather Channel’s lack of coordination with the rest of the meteorological community in rolling out the scale.

By  |  08:02 AM ET, 12/13/2012

Categories:  Latest, Media, Winter Storms

 
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