STORM2K

http://www.wmcstations.com/

US Secretary of Homeland and Tennessee security to issue statement on Union damage in Jackson. Video is live and doesn't show anything right now.

Seems odd to me.. add I also add that I disagree with the rating given to this tornado as well as many others based on pictures I've been looking at. Possibly the teams evaluating them are tired because of the multitude of reports (possibly understaffed). I was looking at the winter weather watches on Feb 5 in the US and and I myself became fatigued when I had looked at about the 150th watch issued. I am interested in this activity because I suspect it may (if combined with other data) be linked to GW.

It has been all over the news this morning.

Interesting article on EF scale and QRT.

http://www.flame.org/~cdoswell/EFscale_rant.html

Politics. Professional mets here care to comment?

Let me a make a specific statement and support it with evidence:

The new EF-scale will cause more tornados to be reported as EF-4 rather than EF-5 vs the old F-scale.

A single or double family residence (single or (double brick?), or concrete block walls) being levelled isn't enough to rate EF-5 according to the EF scale. The highest damage indicator, upper bound is 198 mph 3 sec gust, for a destroyed FR12 (family residence, 1 or 2 family, up to 5,000 sq.ft).

The link to the full EF scale on the spc NOAA website:
http://www.spc.noaa.gov/faq/tornado/ef-ttu.pdf

SNIP from the PDF:

One- and Two-Family Residences (FR12)
Typical Construction
• Asphalt shingles, tile, slate or metal roof covering
• Flat, gable, hip, mansard or mono-sloped roof or combinations thereof
• Plywood/OSB or wood plank roof deck
• Prefabricated wood trusses or wood joist and rafter construction
• Brick veneer, wood panels, stucco, EIFS, vinyl or metal siding
• Wood or metal stud walls, concrete blocks or insulating-concrete panels
• Attached single or double garage

3-sec gust mph mph mph
DOD* Damage description EXP Lowerbound Upperbound
1 Threshold of visible damage 65 53 80
2 Loss of roof covering material (<20%), gutters and/or 79 63 97
awning; loss of vinyl or metal siding
3 Broken glass in doors and windows 96 79 114
4 Uplift of roof deck and loss of significant roof covering
material (>20%); collapse of chimney; garage doors
collapse inward or outward; failure of porch or carport 97 81 116
5 Entire house shifts off foundation 121 103 141
6 Large sections of roof structure removed; most walls
remain standing 122 104 142
7 Top floor exterior walls collapsed 132 113 153
8 Most interior walls of top story collapsed 148 128 173
9 Most walls collapsed in bottom floor, except small
interior rooms 152 127 178
10 Total destruction of entire building 170 142 198
* DOD is degree of damage

If you go and look at the OKC/1999 tornado damage photos, you will see that a single brick family home of much smaller than 5,000 square feet being wiped clean with a slab remaining, but with some debris still on the slab, is listed as F5 damage.

http://www.spc.noaa.gov/faq/tornado/f5.htm

This would not be E-F5 damage. As you can see from the EF scale, vehicles being thrown for whatever distance is not a damage indicator, while a vehicle tossed 109 yard or greater on the old F scale is an indicator of F5 strength. A vehicle being stripped of it's innards and body or thrown over 400 m (a quarter mile) goes beyond this. The net result result of this rewriting will be a reduction of reported EF-5 tornados as compared to the old F-scale, if strictly followed. Looking at the new scale, to my eye the other categories remain comparable to the old F-scale.

Tree debarking only gives upper bound 167 mph (hardwood) according to the EF scale, softwood (lower windspeed) . Not a EF5 damage indicator but it was on the old F-scale. I agree with this, give me a baseball bat and I can debark a tree in a few minutes too. I also agree that the old F-scale wind speeds are not needed to cause F5 damage.

There's something called "synthesis", in which all damage is taken into account, and often includes examples of obscure damage not necessarily included in the scale. For example, if 100% of trees in the path have total destruction kind of damage, it may be estimated to exceed the upper bound. If an entire town of family houses are destroyed (Greensburg), then it's going to be EF-5 (although there were other indicators that that was an EF-5).

But that's my whole point. The old F-scale clearly and explicitly stated that vehicles thrown 109 yards (100 meters) or more is an F5 indicator. It is now gone from the EF scale. The EF scale explicitly gives an upper bound for complete destruction of an FR12 at 198 mph 3 sec gust. Period. There is no mention of synthesis or
obscure indicators. There's nothing obscure about a vehicle with it's frame gone and engine gone and tossed over 100 yards. Yet such a clear damage indicator does not exist in the new EF scale.

This is all I have to say on the matter.

People don't have to follow the scale to the letter. The scale says nothing about damage to cars, but it will certainly impact the final rating if it is impressive enough. The F5 scale was the same way. Adjustments must be made when there isn't quite enough data.

Squarethecircle wrote::uarrow: People don't have to follow the scale to the letter. The scale
says nothing about damage to cars, but it will certainly impact the
final rating if it is impressive enough. The F5 scale was the same way.
Adjustments must be made when there isn't quite enough data.

Sure. I have a simpler solution. The persons in charge of the updating the EF scale should place the vehicle damage indicator back into the list, EXPLICITLY stated, like it is in the old F-scale.

COnsidering how long winded the EF scale is compared to the old one, what's one more sentence under vehicle damage?

Stated EXPLICITLY in the old F-scale:

http://www.spc.noaa.gov/faq/tornado/f-scale.html

F5 261-318 Incredible damage. Strong frame houses leveled off foundations and swept away; automobile-sized missiles fly through the air in excess of 100 meters (109 yds); trees debarked; incredible phenomena will occur.

I agree with the reduction in wind speeds needed for EF-5 damage, debarking going off the list, as I said a man with a baseball bat can cause significant debarking to a tree in a minute, but I'd need a good forklift to move a car a 100 meters.

What are incredible phenomena ?

Don't ask me, I didn't make either scale. I suspect a railway car crushed like it was in a trash compactor qualifies. A purely subjective viewpoint.

For example, incredible damage might include that rendered to the railroad car shown by a link in the thread for the tornado outbreak.

Squarethecircle wrote:For example, incredible damage might include that rendered to the railroad car shown by a link in the thread for the tornado outbreak.

OK, thats a good point. I don´t like that expression but the railroad - car example is maybe usefull. Squeezing that mass of iron might be such a phenomenon...