[NileQueen]

http://visually.visu...bd458d255c5.jpg

Hi All

I didn't know of you had seen this.

FYI
JOanne :-)

[ldavidcooke]

Hey Joanne,

Certainly speaks volumes for living in the wind shadow of hills and mtns. as opposed to the upwind side!

[Nigel Bolton]

Ha! IDC just beat me to it.

Topography appears to play a negative effect on tornnadogenesis in the US. Here in the UK, topography appears to aid tornadogenesis, but spin-ups are generally short lived and tracks short.

N.

[Paul Domaille]

Great graphic NQ, thanks for posting. As Nigel says, topography stands out well, I guess the almost blank area in the north east is the Appalacions ( Yikes, blank moment, not sure if I spelt it right!) Interesting track across Florida which looks F4 or F5, coast to coast....must have been some waterspout for a time. Also the couple of F4/F5 Tn's in the North West.
Cheers,
Paul D

[Ed.]

Wow! up close and personal - in terms of a tornado, many no doubt saw diddly squat!!! great diagram nonetheless great perspective.

[Nigel Bolton]

One thing that is very interesting from a meteorological point of view, is how very similar in direction most of the tornado tracks are, mainly 230-050. However, in the far north, it apprears most tracks follow roughly 270-090. I wonder why this is?

N.

[ldavidcooke]

Hey Nigel,

The prevailing upper level winds during meso cyclonic events. Between roughly 45-60 deg. they likely run close to parallel with the Equator. If tornados occurred in the Arctic you would likely see a CW rotation on the compass moving towards a 315-135 vector.

[NileQueen]

Paul Domaille, on 01 June 2012 - 22:39, said:

Great graphic NQ, thanks for posting. As Nigel says, topography stands out well, I guess the almost blank area in the north east is the Appalacions ( Yikes, blank moment, not sure if I spelt it right!) Interesting track across Florida which looks F4 or F5, coast to coast....must have been some waterspout for a time. Also the couple of F4/F5 Tn's in the North West.
Cheers,
Paul D

Hi Paul, and everyone

Well in the north is New England, and this is sometimes called the northern Appalachians, and considered separately by some.
http://en.wikipedia....chian_Mountains

Yes I see that track across Florida. It would be interesting to know the details of that one.

I am wondering if there were tornadoes in the LGM to late Pleistocene. With sealevel lower, and the Laurentide Ice Sheet (LIS) in North America affecting climate,
would there have been continental land surface where warm and cold fronts could even produce tornadoes?

This post has been edited by NileQueen: 02 June 2012 - 02:05

[ldavidcooke]

Hey Joanne,

Best I can tell, if there is a large stretch of flat land (nlt 100km X 100km) where the upper air current moves at an angle greater then about 40 deg. compared to the vector of the surface wind and there is about a 12-18 deg. differemce in air temperature between the surface to between 8-12km above the surface, there might be a chance.

Add to that a surface RH of over 65% and an elevated RH of less then 35%, yea it might be possible to develop a whirlwind. Add in a difference in wind speed of around 60km between the surface and upper air and you might get beyond a EF0-1 twister...

[zzsladies]

i have lived both places, in alabama where they are frequent and mean, they usually take a familiar track. we would watch the warnings, and judge whether they would come our way or not. but since we have moved, things are changing a bit. the storms are getting bigger and more violent. especially the night tornados they were the worst.
the mountains in bama have a flat top, for many miles, like a platter for the tornados to feed on.

here in west virginia, especially in south east (monroe county) we have a mountain in front of us that sheilds us from storms, including snow storms, i will take pics this weekend, to show it. if a storm comes from the east, it will be a bad one, as the majority come from the southwest. we get very little snow, have a more moderate climate, and have rolling hills. the counties north and west of us start a whole different terrain. summers county has mountains, deep ravines and few rolling hills. there has been only 1 bad outbreak of tornados, and that was in april of 1974. my cousin robin was the only person killed in that outbreak. i remember that night, and the weather that one night was different. we lived on Hump mountain, and heard the tornado cross new river and hit meadow bridge.
that picture of the tracks of tornados is striking. absolutely amazing!
z