Do weak tornadoes matter?

[Dan Robinson]

Should chasers scramble to report weak tornadoes and brief spinups? The chasing community has (at least in my understanding) always operated under the impression that you should report *everything* tornadic, either in-progress or imminent/suspect. However, we see quite a bit of reported weaker tornadoes either a.) not being warned or b.) not making it into LSRs/Storm Data or c.) both, due to the discretion exercised by individual NWS offices. The reason being, the chaser's report is only part of the picture, and a warning for a brief tornado and/or the manpower for a damage survey may not be warranted.

I don't object to that, but it raises the question of if chasers should make the determination from the field whether or not a weak tornado is worth reporting. I'm to the point that I have a good idea of which tornadoes are *not* going to be warned and/or surveyed, so should I still have an urgency to report it? Should chasers make a judgement call if a tornado appears too weak and in a remote area where it's likely no one will suffer impacts?

 

[Todd Lemery]

Hell, just let it go. Unless you've already reported a rotating wall cloud or you want to be able to call it "your" tornado, odds are by the time you hang up the phone, the party is already gonna be over. Of course, if there's volatile conditions, that small spin up could be the start of something big. I guess when you add it all up, i don't have a clue...

 

[Andy Berrington]

In a remote area, debatable. Otherwise...

 

[Jeff Duda]

In the name of science, you should report a tornado if you see a tornado. If you're really unsure if what you're looking at is a tornado or something non-tornadic/non-threatening, then use your best judgement as to whether it warrants reporting to an agency. I can understand if you feel slighted when a WFO ignores or denies your report of a tornado, but at least if you call it in or make the report there's a record somewhere. If you don't even report it, there will never be any chance of it being added to a database. A lot of researchers (myself included) use, or have used, the Storm Data publication or NCDC's Storm Events Database for legitimate research on severe weather, and those databases take raw input from a multitude of sources, including, albeit indirectly, chasers. Sure, that small, brief, weak tornado may still end up never getting into the database, but at least give it a chance.

Again, don't do it for yourself, do it in the name of science.

 

[Dan Robinson]

What I mean isn't a personal feeling about being slighted by an ignored report, but if the NWS will officially ignore a weak/brief tornado (IE, meaning, in turn, that the official "science" record will ignore it), should we also?

The NWS has acknowledged that a tornado report by itself isn't enough to issue a warning and/or do a damage survey. That means that there are cases where a weak tornado will occur and be observed, but not recorded in data due to additional factors (the tornado being brief, the tornado not impacting anything or causing no noteworthy damage). I would contend that most experienced chasers are in a position to know which tornadoes are of the weak/non-warnable/non-LSR-worthy variety, just by virtue of experience and actually being there to witness the event first-hand - more so than someone in an office who only has a radar screen.

Some of the tornadoes that are likely to be ignored by the NWS and/or the official record of reports (which is what makes up our scientific data):

- A non-condensed tornado with brief condensation vorticies and puffs of dirt/plant debris in a field that a chaser observes but does not capture clearly on video.
- A fully-condensed tornado with weak motion
- Any tornado that does not impact structures or cause noticeable tree damage that is not captured on video/photographs
- Weaker tornadoes with low-topped convection that do not have a strong radar presentation (couplet and/or hook), again, which are not photographed clearly

The point is that currently, our scientific record essentially ignores these tornadoes, so should we as chasers do the same when it comes to reporting? Or at the very least, focus more on documeting the event with video and pictures, which in turn might give the event a better chance of being officially recorded in the data later?

 

[Jeff Duda]

Do you know for a fact that NWS offices truly ignore these events and don't enter them into the record? Just because they don't warn on a tornado or issue an LSR doesn't mean it won't get entered into Storm Data. The database is typically filled months after the fact, so unless you have firsthand knowledge that offices don't have records of those events in any part of their own recordkeeping, then it might be premature to assume the tornado truly never gets recorded.

 

[Dan Robinson]

Yes - no records in Storm Data, LSRs, nothing. Reported as it was happening, with more detailed info (video, pictures, GPD/time data, etc) sent in later. Most every chaser who reports can attest to at least one example of this. Two of my personal ones:

July 1, 2013: St. Francisville, Illinois (fully condensed wide cone)

http://stormhighway.com/july12013.php

June 7, 2014: 5 SSW Highland, Illinois (funnel aloft with suction vorticies at ground level)
http://stormhighway.com/blog2014/p-june714tor2a.php

 

[Jeff Duda]

Well then I guess that will happen from time to time. But, at least a record of the tornado exists somewhere.

 

[joel ewing]

I firmly believe that spinups and weak tornadoes should always be reported to the NWS. We all know that they often are a precursor to more substantial development.
Last Tuesday 9-13 I spotted some heavy, rotating cells that nearly went directly over my home. This is a remote area in southeast Arizona north of Tucson that believe it or not, sees at least one or two rotating / tornadic storms annually. Our tornadoes here are usually weak "quick hitters" that are down and up very quickly. They can be both landspouts and meso-born tornadoes. I've been a spotter with NWS Tucson for years and made sure to call them about the rotation I saw. The forecaster confirmed my visual, and in so many words, indicated that since the storms were moving into an area basically void of people, no warning would likely be issued. I understand that.....they've told me that many times in the past.
My main priority when calling the NWS upon seeing rotation was, and I told them this, to perhaps help them fine-tune their radar skills by providing ground truth.

 

[James Wilson]

YES! #WeakTornadoesMatter

 

[JeremyS]

I witnessed a weak non fully condensed tornado with vortices on the ground on 9/15 near Blair, NE. The storm was tornado warned, but never had an official tornado reported. I didn't call in the tornado because it only lasted about 30 seconds and then the storm weakened right away and it touched down in an open field. I sent an email to our NWS office and received a response after 4 days to please send the video and details, etc. I did and didn't hear anything back thereafter. It was probably nearly 2 weeks later the NWS finally came out with a storm event summary from that day on the Omaha NWS homepage. Normally these summaries come out with a day or two. Even though it was 2 weeks later, there was no mention at all of the tornado that touched down in their summary and so far there is nothing on the SPC site either.

 

[Jeff Duda]

I witnessed a weak non fully condensed tornado with vortices on the ground on 9/15 near Blair, NE. The storm was tornado warned, but never had an official tornado reported. I didn't call in the tornado because it only lasted about 30 seconds and then the storm weakened right away and it touched down in an open field. I sent an email to our NWS office and received a response after 4 days to please send the video and details, etc. I did and didn't hear anything back thereafter. It was probably nearly 2 weeks later the NWS finally came out with a storm event summary from that day on the Omaha NWS homepage. Normally these summaries come out with a day or two. Even though it was 2 weeks later, there was no mention at all of the tornado that touched down in their summary and so far there is nothing on the SPC site either.

Just FYI, SPC's storm reports page only includes LSRs issued basically that day. So if no NWS office issued an LSR for the event, or if they only did it days after the fact, the report will probably never show up on that page. Instead wait until the Storm Events Database is updated on NCDC's website (http://www.ncdc.noaa.gov/stormevents/). Takes around 6 months.