On Wed, 30 Jan 2008 17:59:15 -0800 (PST), Russell
sayd the following:

On Jan 30, 7:09*pm, Crackles McFarly wrote:
On Wed, 30 Jan 2008 13:30:32 -0800 (PST), Russell
sayd the following:





On Jan 30, 3:08*pm, Crackles McFarly wrote:
On Tue, 29 Jan 2008 06:15:37 -0800 (PST), LiquidSquid
sayd the following:

Being I live on a hill in just this sort of scenario, here is what I
observe:

Storms tend to "split" as they approach my location from the west. One
half will remain over lower terrain, while the other will head up into
higher terrain. The storms tend to not linger where there is an long-
term elevation change. To my south it is an average elevation of 1500
ft and increases towards PA, to my north, 650 ft and slowly decreases
to lake Ontario. My house is situated on one of the first hills (1300
ft) as you approach Bristol hills from the north, so it is low-lands
and fairly flat to the north, high land and hilly to the south.

It is interesting to watch a storm make like a curve-ball and head out
over the higher terrain away from my location as my gardens wither.
Bristol mountain is the usual target for many of these storms, as it
is one of the highest elevations around at over 2200ft.

The nastiest storms are immediately to my north, which is partly due
to the deeper atmosphere providing more energy, and partly due to
convergence between lake Ontario, Lake Erie, and over land.

In all, even though I am at a higher location, we are in a transition
zone, and more often than not, the storms miss us. In fact it is quite
frustrating as I enjoy a good storm. When we do get a storm, we get a
little more lightning activity, but 600 feet of change from average
topology does not mean much to a 2-mile long lightning stroke.

So to answer your question: There are many more factors than two point
locations that need to be taken into account to predict a trend. In my
location the lakes provide the greater influence over storm paths than
the hills do. Down in PA where they are far enough away from lakes,
the hills have more influence (plus they are larger).

Well I was comparing two cities near me and their storm activity and
recorded severe weather events.

Johnson city TN compared to Chattanooga TN.

JC is about 1,000 ft above sea level Higher than chattanooga, and it
bears out in the noaa data that JC gets far fewer severe events than
chattanooga.

The same goes for the data on the appalachian mountain cities.

It seems the more of a plateau or mountain you're on the less chances
of severe weather.

We have a tiny mountain in town but you could drive your car around it
in less than 5 minutes, so the differences in weather are not extreme
except for winter weather like snow.

Of course their is the odd thing I love about last night. It never
stormed, not even lightening or thunder YET we had a 'severe
thunderstorm warming' because of 58+ mph wind gusts.

Kinda like a flood warning in the desert and it's not been raining.
Weird stuff.

One day I'll get over my fascination with weather but I suspect I
won't realize it since I'll be dead.

Anyone has anything else to add PLEASE do so.

I hate the politico posts just like you do.- Hide quoted text -

- Show quoted text -

Topography certainly can influence the weather, but as
LS points out it is due to more than just vertical
displacement alone. *And one also needs to keep other
factors in mind when looking at things like storm statistics.
Without looking up the climate statistics, I'd guess Johnson
City and Chattanooga are in similar general climate regimes,
but they are separated by enough horizontal distance that
they might not be exactly comparable. *Also Johnson City
is much smaller, at least by population and presumably also
somewhat proportionally by area, than Chattangooga, so
the "target" that each represents for severe weather may
be different. *And larger cities will tend to be in the valleys,
so there is a potential sampling bias from that. *And since
severe weather is comparatively rare, there are possible
statistical sampling differences, although those should tend
to go either way when looking at a large number of different
locations. *I think that just how much such factors account
for differences is difficult to say without careful study. *With
as many variables as there are in weather, it is sometimes
difficult to separate the various contributions.

Cheers,
Russell

I've read up on the severe storms, what ingredients need to be
present.
1. Steep lapse rates.
2, vertical shear
3. low pressure nearby
4. diving jet stream.

1,2,3 or all 4 is needed for severe storms that I've studied. Of
course you can just have excessive heat, 100F+, on a clear day and
have storms popup like mad.

With all those present it stills seems less severe, at least less
frequent, in places of higher elevation.

Am I catching on to this at all?

Perhaps I should pick 2 data points closer as you suggested.

How about Johnson City and Knoxville Tennessee. They're much closer
but the elevations are very different.

The more variables that you're not interested in that you can
minimize the differences of, the better. Other than the summer
I spent in Knoxville, I don't have much experience in the area,
and when I was there it had pretty boring weather. Careful
observation and long familiarity with the weather in an area is
very helpful when one studies such things.


Any opinions?

Also you mentioned severe as being relatively rare but I seem to think
it's more common. Is this because of my location's experience, in
other words am I biased?

In part I was referring to trying to establish differences, and
compared to regular weather one might be interested in, especially
temperatures, severe weather is rare most places. I mean, you have
temperature every day, so the samples are larger than for severe
weather. Also it depends on what you mean by "severe". If you
include all thunderstorms there will be more instances than if you
only consider storms that produce hail, wind, etc. that satisfy NWS
criteria for "severe". I wasn't sure which you're interested in.


I know the overall odds of being killed by a tornado is 1 in 2 million
but if you live in tornado alley those odds approach more like 1 in
500,000

That last number seems low to me if it is per year, but maybe
it's correct. Anyway, you're right that where you live can
make a difference.


Again, am I getting any of this correct?

thanks for your time.- Hide quoted text -

- Show quoted text -

I think you're on the track. During the time I spent in Knoxville,
I think there were two days with severe weather, but it was a
fairly dry summer despite the almost constant forecast of "chance
of afternoon thunderstorms", so you probably have a better feel for
how the weather usually behaves where you live than I do.

Cheers,
Russell


What about a more broad risk of severe weather. Not including
tornaodes, say only severe thunderstorms?

In my city we 'average' 75 thunderstorm days per year but obviously
all those times are not severe.

I made a chart about this for 2007 and the number that actually turned
severe was under 5%.

What made my jaw drop was the local forecasts accuracy, something
around 66% which I thought was low.

I included all surrounding counties and if a drop of rain hit anywhere
I called it correct. 33% of the time they blew it.

But back to elevation. I guess I was trying to find an escape plan by
moving to a higher elevation without having to move west of the
rockies.

I've enjoyed this conversation with you Russell..