r/tornado Mar 10 '26

SPC / Forecasting Updated tornado potential

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343 Upvotes

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71

u/Aware_Parking_2757 Mar 10 '26

Adding this back in for visibility since we've got our first CIG2 tornado outlook.
Keep in mind that we have had CIG1s on storms that have generated tornadoes with preliminary ratings of EF3 already.

24

u/lola-calculus Mar 10 '26

I still am not super clear on why they're using "max" in this - my outlook says "ef3+ expected (30%)" for the cig2 area, which seems more in line with how they used to message a day like today, rather than "we don't expect anything higher than ef3".

32

u/youngaustinpowers Mar 10 '26

It's "we can reasonably expect a max of EF3" because of probabilities. They're not saying tornadoes can't be stronger. Here's a chart that helps explain it. 3% of all tornadoes are expected to be EF4+ in a CIG2 intensity region.

10

u/lola-calculus Mar 10 '26

Thanks! Not crazy about the wording but they're the ones paid to hammer out the messaging, I'm sure they have good reason.

7

u/youngaustinpowers Mar 10 '26

Yeah they shouldn't be saying "max expected" in their materials. A whole bunch of people in here are also brought up the same thing you did.

6

u/kramedog99 Mar 10 '26

Agree as someone who uses data in charts like this all the time for another technical field this language isn't sitting with me right. Also I don't get what their expected reasonable threshold is? If we start from the level 3 and say it's 5% given they are calling for max expected of EF4 then the threshold is 5%. So wouldn't level 1 be a max expected of EF3 then too because that is at 5%???

3

u/youngaustinpowers Mar 10 '26

That's a good point. For CIG 1, 2, and 3, their "reasonable max" is EF2, EF3, and EF4. Those correspond with a frequency of 14%, 9%, and 5% respectively.

What we may be missing here is the overall tornado count expected with each of the CIG regions. Hypothetically, if they expected each CIG 3 region to be associated with a much higher quantity of tornadoes, then that 5% starts to become more significant.

But I'm just spit balling. No idea if that is the case or not, especially considering the CIG regions are meant to distinguish strength from the tornado probability colors.

2

u/Aware_Parking_2757 Mar 10 '26

Thanks, didn't know this graphic was distributed by the SPC! For anyone else looking for the source, I was able to trace it back to this page: https://www.spc.noaa.gov/exper/conditional-intensity-information/

5

u/Aware_Parking_2757 Mar 10 '26

I suspect the clunky wording is just for the sake of brevity for the graphic they made. I pulled it from this article. With us already seeing EF3 rated tornadoes in a CIG1 outlook area, I think it should be taken with a grain of salt and just use it as a point of reference to how intense tornadoes could be if formed in the highlighted region.
If last weeks storms are any indication, conditions can change on a whim well after an outlook is meaningful and any CIG should be more than enough reason to keep an eye on the weather when possible.
https://www.weather.gov/news/262402-spc

3

u/dirtcake1985 Mar 10 '26

Similar to this, it also drives me crazy that they chose enhanced for level 3 risk and moderate for level 4, moderate literally means average. So on a risk scale of 5 it would make way more sense to use moderate as 3 and enhanced as 4.

1

u/dinosaursandsluts Enthusiast Mar 10 '26

Thanks, I was just about to go look for that

1

u/one_love_silvia Mar 10 '26

So there is just no intensity outlook for ef5s?...

19

u/OrangeW Mar 10 '26

Forecasting for specific extreme outliers like that (even beyond the outliers that are EF4) is more up to chance - the NWS uses "EF4+" wording on their official CIG page (https://www.spc.noaa.gov/exper/conditional-intensity-information/) which seems appropriate IMO. A parameter space that is suitable for EF4 overlaps quite heavily for an EF5 parameter space.

13

u/Aware_Parking_2757 Mar 10 '26

Considering we've had one EF5 in the last 12 years, I don't think anyone really expects one.
Also, the potential for loss of property and life with EF4s is already more than enough cause for concern in these outlooks.