Ask the Meteorologists
MIKE MOSS SAYS: Jerry, Your point that semantics could be argued endlessly in trying to establish terminology that can clearly convey relative threats is well taken, but for the time being the National Weather Service, in an attempt to make good use of evolving research that is reaching a point where it allows better estimates of the potential for high lightning rates in advance of storm development (based on observed or model-predicted thermodynamic profiles) or during storm cell development (based on radar observations and how echoes of certain intensity correspond to certain temperature regimes within the storm), has settled on the term "excessive" as one of its descriptors of cloud-to-ground lightning flash rates from thunderstorm cells. As currently used, this falls at the upper end of a scale with the following rough criteria:
Occasional = ~ 1 strike/minute
Frequent = ~ 2-6 strikes/minute
Continuous = ~ 6-11 strikes/minute
Excessive = ~ 12 strikes/minute and higher (corresponds to 1 or more strike every 5 seconds)
You are certainly correct that a single strike is too many if it hits your house or strikes a person. However, if two precipitation cells of roughly the same size, speed and duration pass over an area, and one produces a cloud to ground flash rate of 2-3 per minute while the other produces 20-30 per minute, the odds that SOMEONE's house will be struck are much higher with that storm, as is the relative danger associated with being caught outdoors when the higher strike rate cell crosses an area. In addition, it is not unusual for the higher rate storms to actually produce lightning for longer periods than their less active cousins, so that in addition to the rate difference, there can be an even greater difference in the absolute number of strikes produced.
- My daughter and I were on the bridge over the all American(santa fae)when the car felt like it was moving.We were kinda schocked because we both felt the movement.The car was not moving.The car felt like a movement we have never have happend before.Has there been any indication of a small earthquake? This happened about a week ago. Posted: Nov. 30, 2008
- I have a personal weather station Rainwise mk-3000 and it uploads data to weather underground. Would you be interested in the data it collects as well? If so let me know how to get it to you. I am in the Bahama Nc Area Zip code 27503. Posted: Nov. 30, 2008
- When was the last significant snowfall in Wilson, NC of at least 1 inch? Posted: Nov. 25, 2008
0 Comments
-
Project Education blog
Parents to sound off on reassignment -
-
Research Triangle Rock
Julie Foldesi Brings It On Home
- The Skinny: WRAL Local Tech Wire goes mobile with new site catering to wireless users
- Gaming Guru: Playing games aboard Disney Cruise Lines
- Gardening Gloves: An Easy Way to Go Green | Shop Consignment
- Gardening Gloves: December Gardening Checklist
- Gaming Guru: Playing Games Aboard Disney Cruise Lines


Welcome to GOLO, where WRAL.com visitors can comment on stories and create profile pages, blogs and photo galleries.
You must be a registered WRAL.com user to use these tools. Click here to register or log in.
Stories are open for comments between 7am and 10pm Monday through Friday, but GOLO is always open. Sound off on community issues, create your own blog, upload and share image galleries and make new friends in GOLO!