9/13/08 Disc: MI/AR

[Jason Harris]

Impressive: 5 tornadoes total then? What are the details on the storms that produced them. Cloud height, time duration of rotation, hail (guess there wasn't any severe based on SPC reports?), other wind (wind gust in Brookfield from same paw-paw storm?). What was helicity and diff. types of shear like that day (speed shear, backing winds, etc.?)? What seemed to make 9-13-08 ripe?

 

[Mike Kovalchick]

Impressive: 5 tornadoes total then? What are the details on the storms that produced them. Cloud height, time duration of rotation, hail (guess there wasn't any severe based on SPC reports?), other wind (wind gust in Brookfield from same paw-paw storm?). What was helicity and diff. types of shear like that day (speed shear, backing winds, etc.?)? What seemed to make 9-13-08 ripe?

This MD gives some background for the setup:

http://www.spc.noaa.gov/products/md/md2262.html

 

[rdale]

Your point? I don't think it matters to the people that were hit by a tornado.

It's not often that an EF2 hits in the plains states without even one lightning strike in the associated cell. I found that interesting, and something others might too. Nor would they be aware of.

I don't think there's a threshold of how many tornadoes are within a tornado watch, it's one or a hundred.

The setup that day did not qualify for a Tornado Watch in my mind. (Guess SPC thought so too, or they would have issued one ) I guess that's my point. Cells that did have good rotation produced NOTHING. One storm out of 6 rotating cells produced a tornado, one possible tornado touched down out of a shower with no rotation on radar, then 4+ hours later, a small rotation developed out of a shower and dropped a very brief tornado. Any watch issued would have been canceled long before then.

To say SPC failed because they didn't have a watch, 1) ignores the setup for the day and 2) is asking for too much even if they did know it was coming. If every day with some bit of shear in the low levels around Michigan resulted in a watch, we'd have them all during March and October and 99.5% of them would bust.

Michigan weather isn't the same as Oklahoma when it comes to tornado environments.

 

[Jason Harris]

Did southerly flow from IKE kick in to help this set up intensify? The winds in the MD look westerly but maybe later there was SW or S to shift from veering to backing winds?

This might be something for the education forum also, but I thought backing winds are what is most looked for regarding shear for tornadogenesis but I notice the NOAA glossary contains this about veering as well:

--
Directional Shear
The component of wind shear which is due to a change in wind direction with height, e.g., southeasterly winds at the surface and southwesterly winds aloft. A veering wind with height in the lower part of the atmosphere is a type of directional shear often considered important for tornado development.
--
So is backing at higher levels and veering at lower ideal? But isn't the goal to have as much convergence for inflow to the storm?

Again, we are talking about 5 tornadoes right? 1 in Plymouth and the other storm that Mike cited produced 4 separate tornadoes. So does that make a difference with SPC? Were the warnings timely?

 

[Robert Dewey]

It's not often that an EF2 hits in the plains states without even one lightning strike in the associated cell. I found that interesting, and something others might too. Nor would they be aware of. Sorry that offended you.

No worries... The way it was worded made me believe that you were just nitpicking.

 

[david diehl]

I guess IMO sence there was a MD issued, that should have been enough for affected WFO's to issue some sort of advisory, weather short term forcast, or special weather statement. anyhow, the SPC Did issue a MD, and they ended up NOT issueing a watch, that is fine, but did GRR, or IWX issue a special weather statement, at least not that I saw, so who is being criticized here?
anyhow, it is an event that is over, and all we can do is talk about what happened, not what should have, and should not have been done.
Just my 2 cents.

 

[rdale]

That's worth about $2.74 Good points. An SPS was issued for the cell before it intensified. It was being discussed quite heavily on the IEMChat room, so the media was well aware. Had we not been talking about it, or SPC issued the Meso, many of us would not have been in the office because of Saturday sports shows. So the SPC worked, the SPS worked, and for the most part the TOR worked. Even though the Calhoun Co warning didn't extend into Eaton, I did notify Eaton Co 911 and they alerted, and I did tell people in southern Eaton Co to take shelter.

So the system did the job - even without a formal watch.

 

[mikegeukes]

For the NWS Grand Rapids CWA, there has been 27 tornadoes
for the month of September.

9-13-08 the 4 tornadoes ties the all-time number of
tornadoes in a day for September. You have to go back
to 9-14-90 where 4 tornadoes were reported.

Mike

 

[Dick McGowan]

The setup that day did not qualify for a Tornado Watch in my mind. (Guess SPC thought so too, or they would have issued one ) I guess that's my point. Cells that did have good rotation produced NOTHING. One storm out of 6 rotating cells produced a tornado, one possible tornado touched down out of a shower with no rotation on radar, then 4+ hours later, a small rotation developed out of a shower and dropped a very brief tornado. Any watch issued would have been canceled long before then.

To say SPC failed because they didn't have a watch, 1) ignores the setup for the day and 2) is asking for too much even if they did know it was coming. If every day with some bit of shear in the low levels around Michigan resulted in a watch, we'd have them all during March and October and 99.5% of them would bust.

Michigan weather isn't the same as Oklahoma when it comes to tornado environments.

Yeah I agree with them not issuing a watch when the potential /confidence was not there for their tornado watch "criteria."


I wasn't saying SPC failed, but the way you worded that made it seem as if more tornadoes were needed for a watch.

So yeah, let's not get me started on the EF2. I was watching rotation on radar since before it got into the county with 40+ knots gate to gate. I then called the NWS to find out what the hell was going on and the met said it was nothing to worry about...

Power dimmed, heard a smash and didn't know what it was.

Power went out 3 times and I watched 3 transformers blow up north of me in a line west to east. 5 minutes later the siren went off.

Attached you'll see the velocity image from radar that clearly shows the rotation. Frankly the NWS really dropped the ball on this one and even the SPC for not issuing a tornado watch.

In the attached image my location is the circle and plus symbol.

Why did you call the NWS and bother them, when they are busy issuing warnings trying to warn the public? And why would you ask them "what's going on" when you, I assume, know how to interpret radar?
It seems to me that you're a little pissed off that you didn't see the tornado and decided the NWS and SPC were to blame. Just because there isn't a watch, or a warning, doesn't mean there isn't a tornado on the ground.

 

[Adam Lucio]

I watched the storm move over Paw Paw from home and saved an image of the couplet. Although not the most intense couplet ever it was noticeable enough for me to save an image. The tornado report icon matches up perfectly so I wouldn't doubt a tornado actually touched down.

Pretty good example of a low instability environment that has the right dynamics to produce.

 

[rdale]

Looks like you forgot to turn off smoothing for velocity - make sure you have the latest GR which lets you enable that feature.

 

[Adam Lucio]

It does, I usually switch back and forth when couplets aren't as obvious, in this case the couplet showed up a little better with the smoothing enabled.

 

[Andrew Herron]

Why did you call the NWS and bother them, when they are busy issuing warnings trying to warn the public? And why would you ask them "what's going on" when you, I assume, know how to interpret radar?
It seems to me that you're a little pissed off that you didn't see the tornado and decided the NWS and SPC were to blame. Just because there isn't a watch, or a warning, doesn't mean there isn't a tornado on the ground.

Pardon you sir, I'm coordinator for my county's Skywarn, it's my job to know what's going on so I can relay that information to the EC. Oh, and issuing warnings... no, they weren't issuing warnings and that's why I called.

I called to verify the radar data because I'm not a met and I wanted to make sure what I was seeing was what I thought. I was told it wasn't when in fact there was a tornado.

I'm not placing blame on anyone for what mother nature did, I was simply expressing my dismay for knowing that tornado watches have been issued for less. Perhaps it was my lack of understanding of how things really work...

As for my NWS office, I spoke with the met and he assured me it was nothing (this is mostly why I'm upset...). The media were the ones to get the word out. While that cell did come up fairly quickly, all I've heard has been excuses from other people. I saw the velocity data and it looked pretty clear-cut to me, especially when compared to the other cells that produced tornadoes.

And who the hell are you to tell me why I'm upset? Beacuse I didn't see the tornado?!?! I'd rather NOT see one while I'm standing in my living room. I think you're a bit out of line for even assuming you know me. No, it had nothing to do with SEEING a tornado and everything to do with making sure my family and the people in my community were safe.

 

[Robert Dewey]

I agree with Andrew... given the upstream conditions and knowledge of what types of cells were producing, this one should have been pretty clear-cut. GRR did a fantastic job, perhaps coordination between the two NWSFOs wasn't as good as it should have been.

However, I don't think a watch was necessarily warranted in this case given the low probability for that evening.

 

[rdale]

There was no rotation on any cells when they left GRR's area... That was a new formation - so I don't think interoffice coordination is at fault.