Multi-day outbreak of May 25-31

[Ntxw]

Clearly the EF scale will have to be changed due to wind speeds being recorded now. I think this tornado is causing a good discussion about the EF ratings system though. Despite all the tragedy that came from this event this tornado has caused a lot of discussion from safety to metrology. Although a tornado expanding to 2.6 miles wide in less then a minute still amazes me.

It amazes me too! Changing it will probably be a lengthy process. A lot of research will have to be done about what readings is considered properly done. Things such as where the radar is located, what kind of radars, are there any obstructions, at what height can the readings be taken that is for sure equal to EF5 type winds at the surface. It's much easier to get these readings in open land such as central Oklahoma vs some places in the east. It's the very different variables that results in different outcomes I bet that caused the original EF scale research that they decided to leave out wind readings.

[EF-5bigj]

Well this tornado is a game changer in a lot of ways. It caused the first storm chaser deaths(RIP Twistex) had some of the highest wind speeds ever recorded, grew to become very very large at a very very accelerated rate and it sounds like some of the vortices where moving at insane speeds as well 180 mph just in one of them

[Alyono]

The issue is not with the wind readings, SPC knows this thing will do EF5 damage over populated areas. The problem lies in the Enhanced Fujita scale not the tornado. It's an apples to oranges situation, as I've tried noting before. When the NWS records data for weather (temps, precip, etc) it follows a strict guideline, if it doesn't follow those guidelines the data is often thrown out and rendered not properly collected. There is no guideline in the EF scale about wind measurements, it just doesn't exist. Best solution here is for the SPC to change their stance and include proper guidelines for wind measurements, allow them into the EF scale then retroactively upgrade this tornado and all the others that have acceptable measurements via the guidelines.

Yeah I don't know the other El Reno was also upgraded due to volicity readings. Well I think like the Tuscaloosa tornado the El Reno 2013 EF-5 will be controversial ratings wise. But it's surprising there is disagreement on its rating.

The 2011 El Reno tornado hit homes and other structures that showed evidence of EF5 damage with cars bent around trees, so it was much easier to give the ratings based on damage.

Then remove the WIND SPEEDS from the EF scale!

Some are so stuck on doing things an old and not as good way, that you miss a better way. If you have WIND data to estimate WIND, USE THE DATA before using anything else

[EF-5bigj]

Well I just think the EF scale needs to be updated given technology now we can tell. Wind speeds much better what radar measured the 296 mph?

[RL3AO]

[

Some are so stuck on doing things an old and not as good way, that you miss a better way. If you have WIND data to estimate WIND, USE THE DATA before using anything else

I agree. If you have good DOW velocity data then use it. Also, I suspect if most tornadoes had a DOW next to them, we wouldn't have gone 8 years without an (E)F5 tornado. Its the weakness of the Fujita scale. To be an EF5, it needs to destroy something strong enough to have a potential rating of EF5.

[WeatherGuesser]

Implemented in place of the Fujita scale introduced in 1971 by Tetsuya Theodore Fujita, it began operational use in the United States on February 1, 2007, followed by Canada on April 1, 2013.

The new scale was publicly unveiled by the National Weather Service at a conference of the American Meteorological Society in Atlanta on February 2, 2006. It was developed from 2000 to 2004 by the Fujita Scale Enhancement Project

http://en.wikipedia.org/wiki/EF-Scale

It was just altered fairly recently (6 years is fairly recent) and the old scale was in use for 30 some-odd years, so I expect it might be awhile before any other significant changes.

I've also seen a lot of discussion here about whether the storm in question was rated by including wind speed or only by damage. Some say enough damage was found to justify the rating, but others seem to disregard those comments and insist the rating included wind speed readings.

[Alyono]

This is how a tornado rating SHOULD be derived, IMO

1. Find any in situ obs possible (Only significant one I know is the 2011 El Reno 153 mph wind gust). Start with a baseline.

2. Find any radar derived winds

3. Use damage estimates when there is a lack of any in situ obs or radar winds

[vbhoutex]

Implemented in place of the Fujita scale introduced in 1971 by Tetsuya Theodore Fujita, it began operational use in the United States on February 1, 2007, followed by Canada on April 1, 2013.

The new scale was publicly unveiled by the National Weather Service at a conference of the American Meteorological Society in Atlanta on February 2, 2006. It was developed from 2000 to 2004 by the Fujita Scale Enhancement Project

http://en.wikipedia.org/wiki/EF-Scale

It was just altered fairly recently (6 years is fairly recent) and the old scale was in use for 30 some-odd years, so I expect it might be awhile before any other significant changes.

I've also seen a lot of discussion here about whether the storm in question was rated by including wind speed or only by damage. Some say enough damage was found to justify the rating, but others seem to disregard those comments and insist the rating included wind speed readings.

Wind speed readings were taken by the DOW that was in the area. Only NWS can answer if this was used as part of the determination. Of course, if it is we then have other past storms that have DOW readings available. Should they all be reviewed for intensity determination? I could go on and on here with questions, but the main question is as stated. How was the determination made?

[Ntxw]

The official report that came out from the NWS OUN stated specifically it was this DOW reading that they decided to upgrade. No official statement was given about additional damage being found other than the preliminary EF3. The latest information from NWS headquarters is that there are questions about OUN giving the upgrade not following the guidelines based on damage only which then could invalid the rating going into Storm Data database, which has been the debate between the upper echelon and regional office.

***
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
758 AM CDT WED JUN 5 2013

...UPDATE ON MAY 31 EL RENO TORNADO...

METEOROLOGISTS WITH THE NATIONAL WEATHER SERVICE AND RESEARCHERS FROM
THE UNIVERSITY OF OKLAHOMA AND THE CENTER FOR SEVERE WEATHER RESEARCH
CONTINUE TO INVESTIGATE INFORMATION RELATED TO THE MAY 31 EL RENO
TORNADO.

PLEASE NOTE: THESE DATA ARE PRELIMINARY AND NOT OFFICIAL. METEOROLOGISTS
CONTINUE TO COLLECT AND INVESTIGATE ADDITIONAL DATA.

WITH THIS INVESTIGATION... THE TORNADO HAS BEEN UPGRADED TO AN EF5
TORNADO BASED ON VELOCITY DATA FROM THE RESEARCH MOBILE RADAR DATA
FROM THE UNIVERSITY OF OKLAHOMA RAXPOL RADAR AND THE DOPPLER ON
WHEELS RADARS FROM THE CENTER FOR SEVERE WEATHER RESEARCH. IN
ADDITION... THE WIDTH OF TORNADO WAS MEASURED BY THE MOBILE RADAR
DATA TO BE 2.6 MILES AFTER THE TORNADO PASSED EAST OF US HIGHWAY 81
SOUTH OF EL RENO. THIS WIDTH IS THE WIDTH OF THE TORNADO ITSELF AND
DOES NOT INCLUDE THE DAMAGING STRAIGHT-LINE WINDS NEAR THE TORNADO AS
DETERMINED BY THE HIGH-RESOLUTION MOBILE RADAR DATA. THE 2.6 MILE
TORNADO PATH WIDTH IS BELIEVED TO BE THE WIDEST TORNADO ON RECORD
IN THE UNITED STATES.

.EL RENO TORNADO

RATING: EF5
PATH LENGTH /STATUTE/: 16.2 MILES
PATH WIDTH /MAXIMUM/: 2.6 MILES
FATALITIES: N/A
INJURIES: N/A

START DATE: MAY 31 2013
START TIME: 6:03 PM CDT
START LOCATION: 8.3 WSW OF EL RENO /CANADIAN COUNTY /OK
NEAR COURTNEY ROAD ABOUT 1 MILE NORTH
OF REUTER ROAD
START LAT/LON: 35.495 / -98.095

END DATE: MAY 31 2013
END TIME: 6:43 PM CDT
END LOCATION: 6.2 ESE OF EL RENO /CANADIAN COUNTY /OK
NEAR INTERSTATE 40 AND BANNER ROAD
END LAT/LON: 35.502 / -97.848

$$

SMITH/GARFIELD/SPEHEGER/AUSTIN

[Alyono]

PW Botha once gave this famous quote "Adapt or Die"

Some of the dinosaurs maybe should take that quote to heart. adapt... or the science will die

[EF-5bigj]

Well the EF scale is in for some changes then since regional offices can't agree on the rating. With the radars now we can measure winds way more accurately I noticed under the 200+mph wind speeds it did not say estimated wind speeds. If we can see the wind speeds in real time via mobile radar why not change the EF scale?

[Alyono]

Well the EF scale is in for some changes then since regional offices can't agree on the rating. With the radars now we can measure winds way more accurately I noticed under the 200+mph wind speeds it did not say estimated wind speeds. If we can see the wind speeds in real time via mobile radar why not change the EF scale?

Only change I would like to see is to bring back the EF6 rating, maybe for winds over 250 mph. I'd only recommend using it though for cases of incomprehensible damage (Joplin) or when there are in situ or radar data that show those wind speeds

[EF-5bigj]

EF-6? EF-5 is complete destruction already but I see your point that some tornado damage is beyond EF-5. But I think the issue with a EF-6 to me is that EF-5 pretty much obliterates everything but what would EF-6 damage be exactly? Concrete slabs ripped from the ground or other extreme above average damage?

[Alyono]

EF-6? EF-5 is complete destruction already but I see your point that some tornado damage is beyond EF-5. But I think the issue with a EF-6 to me is that EF-5 pretty much obliterates everything but what would EF-6 damage be exactly? Concrete slabs ripped from the ground or other extreme above average damage?

maybe shifting high rise hospitals off of their foundations, or knocking over a highrise in a downtown area?

[EF-5bigj]

I know the Joplin tornado destroyed the hospital.

[WeatherGuesser]

(Reuters) - In a residential neighborhood near the center of a monster tornado that struck Moore, Oklahoma last month, two partially damaged houses stand like an island among others flattened by the storm.

The walls and roofs of the buildings in a new housing development called Featherstone Addition are still upright while there is nothing left but a concrete foundation where other homes once stood nearby.

The two homes were not completely spared but are salvageable, according to David Prevatt, a civil engineer who saw them when he surveyed the damage after Moore took a direct hit from an EF5 tornado, the strongest rating.

He is convinced that the two houses survived because they were built stronger than most in Oklahoma and the rest of "tornado alley" - the region stretching from Texas to Iowa that accounts for roughly a fourth of all U.S. tornadoes.

"This notion that we cannot engineer buildings economically to withstand tornado loads is a fallacy," said Prevatt, who has studied damage from hurricanes and the devastating tornadoes in 2011 in Joplin, Missouri and Tuscaloosa, Alabama.

http://in.reuters.com/article/2013/06/0 ... 7L20130608

So, since we're discussing the scale and potential changes, what happens to it when buildings are built stronger? Whether through new building codes or personal choice or other reasons, some are built stronger than others and can withstand stronger forces of nature.

If a newer subdivision built to higher standards is in the path of a storm with 250-300 MPH winds and most of the structures survive with lesser damage, should it still be classed as a 5?

[Alyono]

(Reuters) - In a residential neighborhood near the center of a monster tornado that struck Moore, Oklahoma last month, two partially damaged houses stand like an island among others flattened by the storm.

The walls and roofs of the buildings in a new housing development called Featherstone Addition are still upright while there is nothing left but a concrete foundation where other homes once stood nearby.

The two homes were not completely spared but are salvageable, according to David Prevatt, a civil engineer who saw them when he surveyed the damage after Moore took a direct hit from an EF5 tornado, the strongest rating.

He is convinced that the two houses survived because they were built stronger than most in Oklahoma and the rest of "tornado alley" - the region stretching from Texas to Iowa that accounts for roughly a fourth of all U.S. tornadoes.

"This notion that we cannot engineer buildings economically to withstand tornado loads is a fallacy," said Prevatt, who has studied damage from hurricanes and the devastating tornadoes in 2011 in Joplin, Missouri and Tuscaloosa, Alabama.

http://in.reuters.com/article/2013/06/0 ... 7L20130608

So, since we're discussing the scale and potential changes, what happens to it when buildings are built stronger? Whether through new building codes or personal choice or other reasons, some are built stronger than others and can withstand stronger forces of nature.

If a newer subdivision built to higher standards is in the path of a storm with 250-300 MPH winds and most of the structures survive with lesser damage, should it still be classed as a 5?

that is why you CANNOT use damage to estimate wind speeds. That is a PROXY that some old dinosaurs cannot wrap their heads around because "damage is how we've always estimated wind speeds"

[EF-5bigj]

Well I guess they will have adapt to the changing rating standards.

[Alyono]

http://cadiiitalk.blogspot.com/2013/06/ ... uhaha.html

The above is a link that is addressing the controversy

Apparently, the NWS (or Uccellini, not sure if this is his directive or from someone else) favors consistency in the ratings vs obtaining the most accurate ratings.

My 2 cents... favoring consistency over accuracy is 100 percent NON scientific. Part of science is using DATA to obtain the most ACCURATE results possible. Yes, only a relative few tornadoes are measured. However, why not rate those few using the most accurate methods possible? Why use less accurate methods for consistency. How can the data base be used for scientific studies when it is being corrupted for the sake of consistency? Many questions need to be asked if this is downgraded merely for consistency

[EF-5bigj]

http://m.koco.com/news/nws-says-el-reno ... index.html


Seems that would make the tornado even more contriversial well this new to me. This tornado will go down as not only the widest and second strongest but the disagreement over its rating is something I have never seen. So the NWS wants to make it a EF-3 but its a EF-5 that would make the ratings system loose credibility I think it's a EF-5 but they want it rated EF-3? The mobile radar data is more accurate then wind speed estimations. It looks like the Joplin tornado went through some reevauluation as well. http://m.joplinglobe.com/TJG/pm_105310/ ... d=KUrIhx7M