9/19/05 FCST: GREAT LAKES

[David Draun]

I'm waking up to rain and thunder this morning. The actual MCS is north of me, but I have isolated broken lines to my west. It will be interesting to see how this pans out. A recent sounding I read for KLOT has the convective temperatures a bit too high: 86F or higher. We would need a ton of insolation to reach that. The 21z meso-ETA looks the best with over 4000 J/kg of CAPE, and a supercell potential of 60%

 

[Andrew Khan]

There is a supercell potential that is currently SW of MI, and moving North East Towards MI. It doesn't appear their is a lot of CAPE, but I assume that will change as we get into the daytime heating.

 

[j_scheerer]

At this point, I wouldn't be all too surprised to see some decent severe storms in Ontario in the mid to late afternoon (3:30ish EST). We pretty much have the same condiditions as MI and we will have more day time heating on our side.

 

[rdale]

I don't see eastern MI and points east getting much action today - the cloud cover is continuous back to Chicago so you aren't going to get into sunshine. Here in Mid-Mich I'm not as depressed as I was when I woke up to the area of rain moving in, but I'm certainly not excited. Plenty of clearing in central IL extended through IA ahead of the front, where temps are well into the 70's with dews near 70 too. But too much stratus sitting across northern IL / southern WI and I'm afraid we may not come close to realizing the 3000 CAPE that the Eta has by 00z.

- Rob

 

[Robert Dewey]

Originally posted by rdale
I don't see eastern MI and points east getting much action today - the cloud cover is continuous back to Chicago so you aren't going to get into sunshine. Here in Mid-Mich I'm not as depressed as I was when I woke up to the area of rain moving in, but I'm certainly not excited. Plenty of clearing in central IL extended through IA ahead of the front, where temps are well into the 70's with dews near 70 too. But too much stratus sitting across northern IL / southern WI and I'm afraid we may not come close to realizing the 3000 CAPE that the Eta has by 00z.

- Rob

I tend to agree... But, I probably won't let my guard down given the forecast 60-80KNT jet max at 500MB and 60KNT jet max at 700MB. Today just reminds of one of those "well, we didn't expect much because SFC based instability looked too low"... That's just a feeling, and of course feelings are worthless in the weather world :wink:

 

[Andrew Khan]

To bad the high pressure system didn't come through eastern MI, to get rid of the cloud cover. But, for the storms earlier this morning, the line completely broke aprt, and fizzled out southward bound. Was that the storm you guys were forecasting, or another later this afternoon? MD issued for all of lower MI, main threat Large Hail. They think, the cloud cover will be gone later, obviously.

 

[nickgrillo]

I'm not letting my guard down all day...

Insolation is occuring in western MI per the latest VIS SAT images: http://www.spc.noaa.gov/exper/mesoanalysis/s3/1kmv.gif

Deeplayer shear is already >50KNTS and 0-2KM helicity values are already >200M2/S2 (with >500M2/S2 progged by afternoon) in western MI... I'd have to think with any insolation, and at least 500-1000J/KG (with 1000-2000J/KG progged by the RUC by 0Z) of SFC-based instability, we'd have severe convection... Given the raging speed and directional shear at all levels.

There is already upper 60's temperatures into the GRR area...

 

[Robert Dewey]

Originally posted by Andrew Khan
To bad the high pressure system didn't come through eastern MI, to get rid of the cloud cover. But, for the storms earlier this morning, the line completely broke aprt, and fizzled out southward bound. Was that the storm you guys were forecasting, or another later this afternoon? MD issued for all of lower MI, main threat Large Hail. They think, the cloud cover will be gone later, obviously.

The MD only includes the extreme southern portion of lower MI, and that's for the isolated storms near IWX.

I've been watching this clearing making its way towards MI, and it appears to be expanding. I am rather confident that the stuff over southern WI and northern IL will begin to break up as well. So, there should be at least 1 to 2 hours of mostly sunny skies (in the big break), with party sunny skies after. What I am not confident about, is development along the cold front... If storms can re-develop, and provided they are SFC based, then severe weather is likely.

 

[nickgrillo]

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

<!--QuoteBegin-Andrew Khan

To bad the high pressure system didn't come through eastern MI, to get rid of the cloud cover. But, for the storms earlier this morning, the line completely broke aprt, and fizzled out southward bound. Was that the storm you guys were forecasting, or another later this afternoon? MD issued for all of lower MI, main threat Large Hail. They think, the cloud cover will be gone later, obviously.

The MD only includes the extreme southern portion of lower MI, and that's for the isolated storms near IWX.

I've been watching this clearing making its way towards MI, and it appears to be expanding. I am rather confident that the stuff over southern WI and northern IL will begin to break up as well. So, there should be at least 1 to 2 hours of mostly sunny skies (in the big break), with party sunny skies after. What I am not confident about, is development along the cold front... If storms can re-develop, and provided they are SFC based, then severe weather is likely.[/b]

Yeah... It's slowly clearing out, and if you take a look at VIS SAT right now - you'll see a tiny patch of clouds slowly eroding themselves off from Hillsdale county southward into northeast IN.

Take a look at the latest 1630 SWODY1 outlook ( http://www.spc.noaa.gov/products/outlook/day1otlk.html ) and it mentions southeast MI...

I honestly don't think there will be much of a problem today. There is more then ample shear, SFC moisture, and decent SFC-based instability to support supercells when storms form...

 

[Andrew Khan]

Yes it does look like cloud cover is beginning to break off in West/Central MI. But the worry is, will east MI, get any insolation from heating, or will cloud cover keep it away?

 

[nickgrillo]

Originally posted by Andrew Khan
Yes it does look like cloud cover is beginning to break off in West/Central MI. But the worry is, will east MI, get any insolation from heating, or will cloud cover keep it away?

If you look at VIS SAT, you'll see the clouds slowly eroding/burning themelves apart... In fact, there is already a trace a sbCAPE in Sanilac county... Yeah, tiny - But it's only 1:30PM.

I honestly don't think we'll have much of a problem at all today...

 

[Andrew Khan]

Yeah, I see the SBCAPE where your talking about. Do you think eastern MI, will be good to go?

 

[Robert Dewey]

Originally posted by Andrew Khan
Yes it does look like cloud cover is beginning to break off in West/Central MI. But the worry is, will east MI, get any insolation from heating, or will cloud cover keep it away?

I am already seeing FULL sunshine at this moment (not a cloud in the sky, actually), and I am located in eastern lower MI. It does feel a bit more humid out, and with the sun shining down on you, it warms up quickly, My thermometer says it's about 75F, up from 69F.

Clouds to the west are breaking up as I had hoped, it looks like we will get at least several hours of some sun. Temps should hit 80F, barring any significant changes in cloud cover. Td's in northern IL are now in the low 70's...Hopefully this narrow band of moisture will advect into the region.

 

[rdale]

I think the supercell threat goes down dramatically as the afternoon continues, unless it's right along the warm front but I don't think that'll make it too far into southern Michigan. I think a nice line will be our mode of convection later today...

 

[afischer]

Haven't looked closely at this, but at first glance one potential snag for convective chances in southern lower MI seems to be the timing of s/w troughs. A vigorous NNE-SSW oriented s/w is in the process of exiting lower Michigan/northwest OH... makes me wonder if there will be synoptic subsidence for the next couple hours.

Southern lower MI will be south of the next s/w located just in far northern WI now.... which will spin its way across far northern lower MI. Central/southern WI likewise seems to be experiencing subsidence at this time to the south of this next s/w.

FWIW, the 18Z RUC shows CAPE gradually increasing in the warm sector of southwest lower MI, and CINH finally dropping to -40 to -60 by 00Z... but produces negligible QPF and forecasts a not particularly convergent CF.