Biggest Busts/Surprises of all time

[Rob H]

I did a search of the current forums and the archives and didn't really see anything like this - I was curious what some of the biggest forecast and SPC risk busts ever were. Days where everyone was certain there'd be an outbreak, and then nothing close to what was forecast ending up happening.

Alternately, are there many examples of days being significantly under-forecast? It always struck me as interesting that May 3, 1999 was a slight risk until 1630Z considering the power those storms had. I'm reading about the forecast challenges that day at the moment, but I'm sure there were others days like this as well.

 

[Skip Talbot]

Rich Thompson has done presentations on High Risk accuracy. I wonder if any of the slides or notes are online.

List of high risk days:
http://en.wikipedia.org/wiki/List_of_SPC_high-risk_days

April 26, '09 comes to mind for a recent high risk bust. There were some gorgeous tornadoes that day including the one in the ST logo, but overall there were few and very isolated tornado reports that day.

June 17, 2010 comes to mind for a recent even that should have been high risk. There were dozens of tornadoes including several violent tornadoes and fatalities.

Of course SPC didn't do a bad job on these days, its just the limitations of our current ability to forecast severe weather.

 

[Rob H]

Rich Thompson has done presentations on High Risk accuracy. I wonder if any of the slides or notes are online.

List of high risk days:
http://en.wikipedia.org/wiki/List_of_SPC_high-risk_days

April 26, '09 comes to mind for a recent high risk bust. There were some gorgeous tornadoes that day including the one in the ST logo, but overall there were few and very isolated tornado reports that day.

June 17, 2010 comes to mind for a recent even that should have been high risk. There were dozens of tornadoes including several violent tornadoes and fatalities.

Of course SPC didn't do a bad job on these days, its just the limitations are current ability to forecast severe weather.

Hopefully Rich (or someone else) chimes in with a link to those presentations - they sound interesting. Shame on me for not looking at the SPC risk wiki page, especially since I knew it existed. To address your last sentence, I was trying to be careful in my wording to avoid anyone thinking this is that kind of thread, trust me

I was interested in researching the challenges on some of those days when even our brightest weather minds were caught a little off guard by the actual events.

 

[Danny Neal]

*Disclaimer - Not a slam on anyone at NWS/SPC/NOAA*

Under-played day that comes to mind is the oft-talked about 4/20/04 IL/IN outbreak.
Over - played day that comes to mind is the 6/7/07 day in the upper Midwest/Great Lakes
Guaranteed days with bust are any of the following: IA/Iowa/LIE-owa/IAintgoingthereagain/MIMAL's nose (look on the map of the CONUS from MN to LA straight down its an elf!

 

[Melissa Jablonski]

*Disclaimer - Not a slam on anyone at NWS/SPC/NOAA*

Under-played day that comes to mind is the oft-talked about 4/20/04 IL/IN outbreak.
Over - played day that comes to mind is the 6/7/07 day in the upper Midwest/Great Lakes
Guaranteed days with bust are any of the following: IA/Iowa/LIE-owa/IAintgoingthereagain/MIMAL's nose (look on the map of the CONUS from MN to LA straight down its an elf!

I second both of those.

 

[Adam Lucio]

6/18/09. Enough said.

Classic IA cap bust.

 

[Skip Talbot]

6/18/09. Enough said.

Classic IA cap bust.

What's interesting is that the 18th had higher tornado probabilities (15 hatched) than the 17th (10) on the 20z outlook, and it was the 17th that was the big tornado event. I bet there are a lot more moderate risk busts than high risk busts, as its the uncertainty in initiation that often precludes a high risk on loaded gun type setups.

 

[Scott Weberpal]

6/18/09. Enough said.

Classic IA cap bust.

A supercell did initiate before dark in northeast Iowa along the PFT right where the H7 temps dropped off. IMO, certainly not a cap bust.

 

[Adam Lucio]

If the H7 temps dropped off then I would say that storm went up in an area where there wasn't a [strong] cap.

http://www.spc.noaa.gov/products/md/2009/md1210.html - IVEN THE DEGREE OF INSTABILITY...50-60 KT OF EFFECTIVE BULK SHEAR
AND RATHER STRONG LOW-LEVEL SHEAR ON COOL SIDE OF
BOUNDARY...ENVIRONMENT WILL SUPPORT INTENSE SUPERCELL DEVELOPMENT
WITH THE THREAT FOR VERY LARGE HAIL...DAMAGING WINDS AND POSSIBLY
STRONG TORNADOES.

http://www.spc.noaa.gov/climo/reports/090618_rpts.html

Thats a bust for tornadoes and it was caused by a stout cap. IMO that spells cap bust.

 

[Scott Weberpal]

That's when analysis products come into play so you're in the area not under the influence of a strong cap

I know I know, this is about SPC busts; but I love picking on the people that call the day a total cap bust.

4/6/01 will forever stick in my mind.

 

[Paul Sherman]

2 That come to mind from 2010 were either side of what the original poster wanted.

31st May - Campo Tornado SPC Had Slight Risk with 2% Tornado Probs, they surely were not envisaging one of the most Photogenic Tubes in 6 Years, Most if not all of the Discovery Players did not even deem this day sufficient to Chase given the low probs.

1st May although not a Cap Bust was a very forgettable High Risk in Arkansas for many, Strong Wording if I remember rightly with SPC Going with "Corridoors of Strong to Violent Tornadoes" and RUC/WRF even had that corridoor of Supercells predicted on the Models complete with associated Hook's, the reality was no where near with most scratching around hazy almost non descript looking Storms.

Pretty much all of May 2005, 2006 & 2009 falls into the Crapola Bustola Category as well - Lol

Paul S

 

[Skip Talbot]

I think the original intent was more about what events busted from a forecast standpoint. Regardless of how photogenic the Campo tornado was, there were only 5 reports that day, and how many actual tornadoes were there? Three? I could see SPC going with a localized 5% over that county, but the day definitely did not deserve more than a slight risk. If SPC knew ahead of time that the most photogenic tornado was going to form somewhere over SE CO (along with a couple other tornadoes) and that it would be one of the biggest chase days of the year, they'd still just issue a 2 or 5%. On the other hand 5/1 had over 40 tornado reports and fatalities, which I'd say merited the high risk.

 

[Dean Baron]

June 5th, 2008 High Risk (30% hatched TOR risk) bust in Iowa. If you look at reports from that day, it doesnt look like a bust. Bust if you were sitting in western Iowa that day like I was, you know the reports are deceiving.

 

[Paul Sherman]

Skip

Sorry I must have misread the meaning of what the OP Needed

I was replying mainly to the "Surprise" Part of the original posters question, the Surprise being such an amazing Tornado on a day most would not even deem worthy of making the trip to SE Colorado, not dissing what the SPC Put out as I agree with their prognosis given what ingrediants we had to play with.

And I did not know Arkansas had 40 Tornadoes that day, I was on the Pine Bluff and the Big Monster than came up from Monticello that crossed into Tennessee and might have seen the De Witt Nighttime Tornado and we were virtually in the hook area for about 100 miles, what part of Arkansas were these 40 Tornadoes that were reported or are you referring to the Late Night Outbreak on the 30th/1st that affected the Little Rock to Scotland area ?



Paul S

 

[Skip Talbot]

42 tornadoes reported. Less than that number actually materialized because of duplicate and false reports. Although there were tornadoes within the high risk, most of the reports came in outside of the 30 hatched. The perfect outlook would have extended out to include these areas, and maybe downgraded portions of AR to a moderate risk, but the day wasn't a complete bust with 0 tornado reports.

The day was a disappointment from a chasing standpoint. I think weak low level lapse rates were partially to blame, along with pwats that were too high (if there is such a thing). It seems with that combination, you usually wind up with messy, rainy HP storms lacking in hail and low level storm structure (including tornadoes). The terrain, apart from the AR floodplain, is also less than favorable across that risk region, and HP modes are the standard down there. Definitely a tough chase, and one I'm glad I opted out of.

Campo and 5/1 bring up good points about how chasers should not get excited over SPC outlooks. Its the lower risk days that are often the best chase days and the higher risk days that are the most frustrating and disappointing.