View Full Version : Severe Weather Trends



venture
04-26-2012, 12:50 PM
Breaking away from our normal discussion, this is more generalized over years. This information is from the SPC at: http://www.spc.noaa.gov/wcm/. I'm just going to start at the top of the page and work down discussing it. I'll add a few images here to highlight some stuff.

First part is the tornado for April. We are sitting around 130 so far nationally which is right on our 60 year average. A huge difference from the major record breaking April last year of 758 tornadoes which beat the previous record of 264 (Super Outbreak of 74). Overall trend does show tornadoes increasing during April. Whenit comes to strong tornadoes (EF2+) we are at 17 now which is below average of 36. Last year we had 166 which beat the Super Outbreak in '74 that had 157. The trend here is that strong tornadoes are on a decrease in April.

The next part hit on the High Risk April 14th outbreak. It is pretty amazing how well their forecast did so far out.

http://www.spc.noaa.gov/wcm/2012/outlooks-dy8-dy1.png

Looking at the graphic the northern and extreme southern portions of the high risk didn't verify, but the central part definitely did. All in all, can't really criticize the forecast that much. They nailed an outbreak coming several days out and that is tough to do.

2011 Tornado Summary Maps

This really put last year in perspective. Six EF5s and they show up very well on this map.

http://www.spc.noaa.gov/wcm/2011-jan-dec.png

Average Number of Tornadoes
30 Year Average: 57 (4th) ; 20 Year Average: 62 (3rd) ; 10 Year Average: 54 (8th)

Average Tornado Deaths
30 Year - 3 (tied 6th) ; 20 Year - 4 (tied 4th) ; 10 Year - 2 (tied 10th)

Average Tornadoes per 10K square miles: 9 - ranking us tied for 3rd

Number of tornadoes per county...
http://www.spc.noaa.gov/wcm/ustormaps/tornadoes-by-county.png

Annual Tornado Maps Checkout: http://www.spc.noaa.gov/wcm/annualtornadomaps/

There you can see how things setup each year. Some are very focused in specific regions and others are very evenly spread. Central OK has really been a major focus since 2003/2004.

Running Totals for the Year - so far we are ahead of the curve and above average. Something to keep in mind as we are in peak season now.

http://www.spc.noaa.gov/wcm/ptorngraph.png

Another set over interesting maps...

http://www.spc.noaa.gov/wcm/2011-wbc-anoms.png

http://www.spc.noaa.gov/wcm/2010-wbc-anoms.png

http://www.spc.noaa.gov/wcm/2009-wbc-anoms.png

http://www.spc.noaa.gov/wcm/10ytora.gif

http://www.spc.noaa.gov/wcm/10ysvra.gif

ljbab728
04-26-2012, 09:51 PM
Obviously some of those figures are skewed a little due to the size of the counties involved. To be more accurate it would need to be based on a certain number of square miles instead of counties.

venture
04-26-2012, 10:35 PM
Obviously some of those figures are skewed a little due to the size of the counties involved. To be more accurate it would need to be based on a certain number of square miles instead of counties.

Its not really that far off. The mega size counties are mainly saved for mountainous areas. Getting into that region there is very little in the way of severe activity anyway. You can't really do it by square miles because watches are assigned on a county level, not by a specific outline. If they had done it by county warning area then that would be one thing, but per county is the most accurate way.

ljbab728
04-26-2012, 11:12 PM
Its not really that far off. The mega size counties are mainly saved for mountainous areas. Getting into that region there is very little in the way of severe activity anyway. You can't really do it by square miles because watches are assigned on a county level, not by a specific outline. If they had done it by county warning area then that would be one thing, but per county is the most accurate way.

I realize and understand all of that, venture. But to a casual observer some of the maps would give a false inpression for some areas. (south Florida for example)

venture
04-26-2012, 11:20 PM
I realize and understand all of that, venture. But to a casual observer some of the maps would give a false inpression for some areas. (south Florida for example)

South Florida looks about right. They rarely get severe weather outside of landfalling tropical systems. They get a handful of watches a year it would seem but not nearly as much as those further north. So I still don't see where any false impression would be coming into play.

ljbab728
04-27-2012, 12:23 AM
South Florida looks about right. They rarely get severe weather outside of landfalling tropical systems. They get a handful of watches a year it would seem but not nearly as much as those further north. So I still don't see where any false impression would be coming into play.

Check out your first map, venture. The one showing the number of tornados per county.

venture
04-27-2012, 07:43 AM
Check out your first map, venture. The one showing the number of tornados per county.

That makes a bit more sense...I was looking at the others that focused on watches and such since that is the majority of them. LOL They probably could go back and break it down even more, but it would take a significant amount of time to create I would think.

silvergrove
04-28-2012, 08:26 AM
That one county in Colorado get a lot of tornadoes!

OKCisOK4me
04-28-2012, 09:19 AM
That one county in Colorado get a lot of tornadoes!

That's the same thought I had.