Biggest Slight Risk outbreaks

[Brendon Lindsey]

Well I was just curious to know of the top of your head, are there any slight risk days that really caught your attention, such as a outbreak... I have been a little bored lately and was looking at the Severe Weather Index and noticed some slight days have had more tornadoes than Moderate risk days. This will hopefully encourage my attention when a slight risk is issued for here in N. OK.

Thanks for your time,
Brendon Lindsey

[Mikey Gribble]

I know the May 3, 1999 outbreak was a slight risk all the way up to the Day 1 outlooks. I don't remember if they upgraded on the first day 1 outlook or if they waited until the second one. It made it to high risk by that afternoon though.
I don't remember any major outbreaks on slight risk days. The Attica/Harper county storms was on a slight risk day. That storm produced an F3 and and F4 in addition to 9 other tornadoes (according to the survey). As far as I know that's pretty damn unusual to get a violent tornado on a slight risk day.

[Dan Cook]

4/20/04 was a slight risk

[Chris Lott]

Here's a good article from SPC with forecasting issues they had with the May 3, 1999 tornado outbreak, which did start out as a slight risk.

http://www.spc.noaa.gov/publications/edwards/3may_spc.htm

[Kenny Drake]

As previously mentioned, 3 May 99 is the first outbreak that comes to my mind. The models had major issues with the mid to upper level features right up until the day of the event. Just goes to show the importance of looking at real-time data on chase day, prior to picking a chase target or deciding to go out at all.

[Mike Hollingshead]

http://www.spc.noaa.gov/climo/reports/051112_rpts.html

http://www.spc.noaa.gov/climo/reports/040707_rpts.html
These don't look like they were even in the 13z slight risk. Close.

[Ben Prusia]

I can definitely vouch for 7/7/2004.

The Russell supercell was definitely one of the best structures I have ever seen. The supercell dropped tube after tube on its very slow east-southeast trek. I would suppose the SPC never issued a tornado watch due to the very localized tornadic threat as the Russell storm was the only major tornado producer. I was still very new to storm chasing during this chase as I watched the storm from a gas station along I-70 east of Russell, I have attached some pictures from my chase that day. Sorry they aren't the best of pictures but my photography skills have improved since then.

[David Drummond]

As previously mentioned, 3 May 99 is the first outbreak that comes to my mind. The models had major issues with the mid to upper level features right up until the day of the event. Just goes to show the importance of looking at real-time data on chase day, prior to picking a chase target or deciding to go out at all.

Words to live by there Kenny. Spend way more time looking at what is going on real time that what computer models are telling you the day of the chase.

[JIM SELLARS]

Jan 7 2008....In SGF's CWA...33 tornadoes and a PDS watch all in a slight risk

[Tim Gonyo]

8/18/05 - S. WI tornado outbreak. Slight risk at least until event unfolded. Downplayed event severely due to morning convection that crossed area. Highest tornado risk of 5% was actually over N IL for a bit.

[Simon Brewer]

May 12, 2004: South Central KS Tornadoes, but one should not judge a chase day on SPC outlooks; outlooks are for NWS offices not chasers. I actually get a little annoyed when people countinually refer to the SPC outlook regarding a previous chase day or potential chase day, and I imagine some of the people at the SPC feel the same way, because they are forecasting for the public, not storm chasers.

http://www.stormgasm.com/5-12-04/simon%20pics/tornado1.jpg

[Mikel Shively]

4-10-08, 26 of the 28 tornado reports were in the slight risk, the other 2 was in the moderate.

[Shane Adams]

May 12, 2004: South Central KS Tornadoes, but one should not judge a chase day on SPC outlooks; outlooks are for NWS offices not chasers. I actually get a little annoyed when people countinually refer to the SPC outlook regarding a previous chase day or potential chase day, and I imagine some of the people at the SPC feel the same way, because they are forecasting for the public, not storm chasers.

http://www.stormgasm.com/5-12-04/simon%20pics/tornado1.jpg


Simon beat me to the punch on this one....surprised I made it to page 2 before seeing this date mentioned.

[afischer]

Cold core events can really go bonkers when the stars line up right. 06/06/99 was like a cold core set-up on steroids in northeastern ND, with ~20 NNW-moving tornadoes including a couple F2s and an F4. 05/17/00 (Brady day) had numerous (non-supercellular?) tornadoes near the mid-level low center over northeast CO... some causing damage. Not atypically, both events had MDT risks farther to the east in association with stronger potential instability and stronger low-level/deep layer shear profiles. Cold core set-ups can obviously be pretty fickle, and highly dependent on mesoscale details... seems rather subjective what size of tornado probabilities each case warrants.

[Terry Tyler]

2/17/08 was pretty bad for a slight...it was a high end slight though...

http://www.spc.noaa.gov/products/outlook/archive/2008/day1otlk_20080217_1300.html

http://www.spc.noaa.gov/climo/reports/080217_rpts.html

same story goes for 1/07/08...both events had well over 45 tornado reports...

http://www.spc.noaa.gov/products/outlook/archive/2008/day1otlk_20080107_1300.html

http://www.spc.noaa.gov/climo/reports/080107_rpts.html

[Greg McLaughlin]

This event had a slight risk which extended from IL southwest into eastern OK and northeast TX. Several tornadoes were reported in IL, while an intense supercell developed in eastern OK and drifted south/southwest as it continued to backbuild into the Theta-ridge. This storm produced 7 or 8 tornadoes including an F2 in Muskogee and two F3 tornadoes (one at Sequayah State Park and the other near Checotah.

[Darrin Rasberry]

because they are forecasting for the public, not storm chasers.

This is truth. The NWS uses several different models, and as we've seen this year, the models can diverge significantly until and including the day of the storms. Often, for very strong storm days, the NWS will issue a SLGT until several model elements verify.

Before the day of a chase, models are all anyone has. For me, they are good only to the extent of figuring out where to set up, or approximately where to crash for the night if the chase is going to be a long-distance one.

It is not of course for chasers - as a chaser for the first time this year, I've had to ask myself things the SPC won't tell you all the time. What does the terrain look like? Are the storms going to be moving 65 mph? Is the event going to be primarily at night, when I can't see?

If you're going to use the SPC as a guidebook, as it should be used, they might issue a SLGT even though a very localized tornado event may occur - something you might miss if you "don't feel like chasing a SLGT." I check the models, opinions from other chasers here, and my own hunches before the day - then on the day itself, we set up our best guess and go by our eyes from there.

To contribute to the thread, I of course haven't remembered very much, since stormchasing is new for me, but the aforementioned January outbreak was SLGT if I recall correctly, and I believe included a tornado (in Wisconsin) out of the area entirely. If you're strictly speaking, '99 can't be considered a SLGT, since it was upgraded (although during the day-of).

[Jim Bishop]

Nov. 12, 2005 tornado outbreak unfolded over Central Iowa. I believe there were over a dozen tornadoes reported in Iowa that day. SPC had a slight risk all day. Below is the Aimes/Gilbert, Iowa tornado.

http://www.stormgasm.com/11-12-05/still1.JPG

[Jonathan Behle]

I remember last June we had a really nice storm and not a bad outbreak around Ness County Kansas that was only a slight risk.. It had me kicking myself we did not make the drive out there because the SPC downplayed it quite a bit! It wasn't a huge outbreak but I thought it warranted a moderate risk atleast!


Unfortunately my memory usually only remembers the big outbreaks, and when the SPC forecasted a Mod or High that didnt pan out at all!

[rdale]

May 12, 2004: South Central KS Tornadoes, but one should not judge a chase day on SPC outlooks; outlooks are for NWS offices not chasers.

I'm not sure I understand your comparison... I don't think an outbreak occuring in a slight risk area can be considered a hit no matter how you define their forecasts? The question wasn't about 'slight risk chase days' but 'slight risk outbreaks'.