4/17/04 NOW: IA/MN

[Robert Dewey]

Originally posted by mikegeukes+--><div class='quotetop'>QUOTE(mikegeukes)</div>

0940 PM TORNADO 3 E MASON CITY 43.15N 93.14W
04/17/2004 CERRO GORDO IA BROADCAST MEDIA

PUBLIC REPORT VIA KIMT TELEVISION.

Mike[/b]

<!--QuoteBegin-rdewey
...Looks like storms have a nice discrete structure, wouldn't be surprised to see a report of a isolated tornado (weak) in the cell just northwest of Mason, IA...

Robert

Called it pretty close on that one...Guess I got lucky for once, too bad I'm not chasing it though :cry:

Robert

 

[mikegeukes]

Severe Weather Event is over, removed information.

Mike

 

[Shyanna Busch]

two mesos West of Lacrosse, WI. Both of them have very prominent hooks on radar, but no warning asof yet.

 

[Lance Maxwell]

Mention of trucks being blown over on I35 in NWS warning reports. Man, those cells just look awesome.......I can only wish they were down closer to here.

 

[rdale]

ARX is too far north of the front (for now) to get rotation to the ground...

 

[Robert Dewey]

Originally posted by rdale
ARX is too far north of the front (for now) to get rotation to the ground...

I agree...Quite a bit of elevated instability, mainly a hail threat. RUC2 actually struggles to take the warm front up into that area, until late tonight, so expect mainly elevated storms.

Check out the NEXRAD from ARX...Click on the loop, watch the cell in southeast MN take a nice right turn...Wish I was there! - http://weather.cod.edu/analysis/paulradar.pl?ARX

Robert

 

[Lance Maxwell]

Looks like that cell just made a quick turn back to the North and has definitely lost its defined hook.

 

[Robert Dewey]

Originally posted by Lance Maxwell
Looks like that cell just made a quick turn back to the North and has definitely lost its defined hook.

Yeah, they crossed over the warm front and became elevated, losing the low level rotation. With VIL's still in the mid 50's, I'm betting large hail is still falling...

EDIT: For those interested, here is the RUC2 forecast sounding from earlier...Sorry about the text size, but the basic thermodynamic and hodograph structures are readable - http://www.waveformpc.com/sounding.jpeg

Robert

 

[rdale]

Most tornadoes come north of the warm front in these sort of cases - exactly what happened when MI got over almost twenty tornadoes from a warm front moving north in May 2000. They all were in the cool air north of the warm front.

 

[Robert Dewey]

Originally posted by rdale
Most tornadoes come north of the warm front in these sort of cases - exactly what happened when MI got over almost twenty tornadoes from a warm front moving north in May 2000. They all were in the cool air north of the warm front.

The sounding above must have been right along the warm front, since instability is very close to being elevated in the 850MB to 700MB level...My thought is that the storms need to be very close to the warm front. Either south of it in the SFC based instability (but not so far south as to lose the good low level shear), or slightly north of it where instability is slightly elevated (~900MB/950MB), but not enough to really impact the LFC height too dramatically, so rotation can still reach the ground. In either instance, low level shear and helicities are very impressive, which could compensate for the slightly elevated convection a bit further north. As you mentioned, this was the case in MI on May of 2000.

I believe tonights storms were rooted right on the warm front, with maybe a couple to the south and a couple to the north, it was very interesting to say the least.


Robert