8/27/2004 FCST: Great Lakes

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Potential for severe weather on Friday in the Great Lakes I believe. At least the models think so... :)

Opinions appreciated:
 
CAPE 5300, LI -11 on the Eta for 21Z Fri... Not bad... However lapse rates and low-level winds a bit weak (where have we heard that one before.)

GFS looks a little faster but still spits out CAPE 2500 LI -7.

- Rob
 
looks to be very unstable friday, but it also seems to be a day that is lacking in dynamics. There also seems to be a pretty strong cap forecasted that day and we all know what that means :(
 
Read GRR dis. wrong, thought they ment friday, really ment thurs. my bad. Hopefully something goes, kinda takes me back to last aug. 21st when there was a cap that broke with rapid development over eastern lower.
 
00Z Eta caps us through 15Z, then allows for explosion in the afternoon with CAPE > 4000, LI < -10, EHI > 6 for Mid-Michigan! Does not develop ANY precip though, even with fropa around 00Z-ish, possibly due to weak lapse rates & convergence?
 
possibly due to weak lapse rates & convergence?

Well, according to my expert analysis (yeah right, LOL)... I would have to say this is correct. I havn't really been following the models the past few days, and was quite surprised when I found this thread (and looked at the 00Z ETA). Looks like a good setup, as Rob said though, there is no precip output on the model. That would lead me to believe at this point, that storms will be the isolated supercell type, with a good chance at tornadoes and damaging winds, but a little iffy on the hail (weak lapse rates), though with strong updrafts and CAPE of 4000J/KG, I wouldn't rule it out at all.

Off to do a full model analysis (havn't fully looked at he data/soundings)... :eek:
 
Does not develop ANY precip though, even with fropa around 00Z-ish, possibly due to weak lapse rates & convergence?

Thats also what i'm worried about, also is it possible the storms from thurs night will move eastern and clouds us over for the morning hours? I tried looking at the ETA storm vect. but it says page can't be found. My guess is they would move ENE or NE away from lower mich.

Time will tell, thursday looks huge west of here.

EDIT: just looked at the new 0z eta sev. wx page and see that it has slightly higher lapse rates then the 12z run, hopefully a trend to contiune. It also has large area of 200-250 3 KM Storm Relative Helicity over lower mich. at 18z. If the rates improve a little more and there is some covergence Watch Out.
 
New Day 3 is out, mentions no risk of severe weather
for the Great Lakes, only isolated strong storms may occur..
Parts of Kansas and Missouri has the slight risk.

Mike
 
latest ETA is a little faster with the front and also has alot of convection at 12z friday morning over the western part of the state, more then likely whats left of tomorrow's outbreak across wis, minn, etc. so that could be why they downplay the threat of severe weather for friday.
 
"Went from pretty good to Noda, zitch, zero, nothing. "

???? CAPE 2500, LI -9, lapse rates > 7 C/km, EHI approaching 2, helicity > 100 is far from my definition of nothing... Note SPC does have us in drawn in for Friday - just not as confident (understandably) as they are over the Midwest to go with SLGT.

- Rob
 
"Went from pretty good to Noda, zitch, zero, nothing. "

???? CAPE 2500, LI -9, lapse rates > 7 C/km, EHI approaching 2, helicity > 100 is far from my definition of nothing... Note SPC does have us in drawn in for Friday - just not as confident (understandably) as they are over the Midwest to go with SLGT.

- Rob

It's hard to believe the SPC is not confident for this kind of situation. Huh? CAPE 2500, LI -9, Helicity >100.

A little odd.
 
lapse rates also apper better with the 12z eta, so thats two runs in a role now that they have improved the rates, i would think by tomorrow there will be a slight risk over lower mich on friday in the day 2 outlook.
 
"It's hard to believe the SPC is not confident for this kind of situation. "

Because the models don't generate any convection with the fropa, and it's still 3 days out... I'm not confident either - and note that they do have us in the 5% area so I wouldn't have expected much more than that at this timeframe. I don't think they're nuts - just realizing the number of times the model has been horrible in convective forecasts at 36+ hrs for the Great Lakes this summer.
 
is it possible the storms from thursday race east overnight and cause a damaging wind event in the wee hours of friday morning over lower michigan. Rdale, your an expert met., what's your opinion?
 
There's no way of forecasting 1) MCS initiation point 24 hours away 2) path and speed of that MCS that you don't know where will begin and 3) extent of the damaging wind zone 36 hours away for a MCS that forms in an unknown location at an unknown time and moves at an unknown speed and direction. All you can look at is the overall setup...
 
APX is hinting that there could be a squall line that races into northern lower thurs night/friday morning. How far south this would be, if it does indeed occur would be pretty important, i could see an outflow boundry somewhere across the state which could fire severe storms in the afternoon.

IT LOOKS LIKE A SQUALL LINE WILL DEVELOP THURSDAY
AFTERNOON ACROSS WI/MN...PROPAGATING QUICKLY EAST ACROSS NORTHERN
MICHIGAN THURSDAY NIGHT
 
well, we went from no convection with the front to what looks like too much. The forecast is for clouds during the morning, limiting heating and thus the severe threat in the afternoon. Timing looks pretty good and if there are less clouds then what is forecasted, it could get interesting tomorrow afternoon.

Anymore thoughts on tomorrow would be great.
 
Not much has changed - if we heat up it could get nasty, if we stay clouded in the lack of instability and weak lapse rates mean nothing good will come...
 
My friend told me Forbes said tornadoes are possible in MI tomorrow. Don't know any more details, nor do I really know how this is possible - but he said it. He'll probley say it again at 9:30.
 
well, storms rolled across the state this morning and i thought that was it for severe chances this afternoon, figuring clouds would be the rule for the day. Wow was i surprised to see most of the state in mostly sunny skies and already near 80 at 10am. This should really help our chances for the afternoon, but the SPC still says too much uncertainty for a slight risk.
 
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