10/26/2010 FCST: IN/MI/OH/IL/KY/TN/MS/AL/GA/PN

[Zack Hargrove]

The other thing that makes this setup look even more interesting is that the models are trending towards an extremely tilted trough axis towards the east. This will allow more warm air advection, which could pump even more instability into the atmosphere. This was one of the main factors that helped the great outbreak of 1974. Now, am I comparing these two events? Of course not. I am not even willing to say there will be a tornado outbreak yet, but with the way things are going... I would not be surprised if we had a substantial outbreak. There should be a bunch of severe stuff regardless!

 

[Robert Dewey]

Looks like the NAM came back to reality on the 12z run (it is now sub-960mb). Still looking for a 18-21z frontal passage here in eastern MI / western OH, which isn't too bad. The one thing that I don't like about this system is the lack of mid level cooling, which translates into a limitation of instability. I think the severe weather setup is more similar to 19981110 than 20011024 for that reason, although there is a higher level of moisture content and dramatically better directional shear (was able to pull the archived 12z/0z soundings from the '98 event).

So, I'm anticipating a widespread damaging wind threat (discounting synoptic winds for the purpose of the Target Area)... probably to the same extent as the 20011024 event... with a much more mitigated tornado threat. However, the degree of shear - possibly enhanced in the presence of the cold front - does make me wonder, but it's just hard to scream "tornado outbreak" when you're relying solely on kinematics to compensate.

From a historical perspective, we're probably looking at one of the strongest storm systems to hit the Great Lakes in recorded history. The depth of the surface low and expansiveness of the wind field blows the 1975 event out of the water, and surpasses both the 1998 storm and the 1940 Armistice Day storm. One interesting fact is that with each of these storms (Armistice Day storm?), tornadoes did occur.

 

[Ryan Wichman]

In line with what Robert just said, the 12z NAM is back to a slightly faster solution which seems more reasonable. That will not allow the atmosphere to reach peak heating in IL or much of IN, but to be fair...look at the central plains right now. There is so much cloud cover. I wouldn't expect any breaks (but look out if they do happen).

I will keep the historical archiving to a minimum since previous posts have covered that end of the spectrum well. But it doesn't take a 20 year veteran to know that a 70kt low level, 80 knot mid-level and 120 knot upper level jet is going to create some chaos. These storms are going to be cranking...don't expect a chase, anticipate to be blown over!

Here is Quincy, IL it looks like the frontal passage will occur around the 4am time frame. Not the greatest time for severe weather traditionally, but with a moisture rich and relatively warm (for overnight) atmosphere LFC's and LCL's are near maxed out below 3600 and 1600 feet respectively. Storm mode still seems a bit muddled, but for the most part I would expect bowing segements. With such a dynamic storm system though, any discrete storm allowed to play in it's own environment would become very dangerous. With the amount of forcing though, that seems tough in the great lakes region.

For those SPC lovers out there, I fully expect a moderate risk upgrade for both the overnight hours tonight and for the central great lakes tomorrow. Below are both the SREF 500mb analysis for 9z TUES and a sounding near frontal passage in Quincy.

 

[Joel Wright]

Midwest Superstorm

Anyway, the new 12z computer guidance is deepening the storm to as low as 955mb per RGEM. Several other models drop the surface pressure to sub 960mb as well by late Tuesday afternoon. The record lowest pressure in Minnesota is currently 963mb, which was set back in November of '98.

This could be a truly historic storm if it deepens to the magnitude indicated by most of the models. Another important aspect of this storm will be the longevity of the impacts. The storm looks to basically sit and spin over the upper Midwest through Wednesday as it gradually fills. Not only will this cause prolonged damaging wind potential over land, but this gives the Great Lakes (particularly Superior) more time to generate enormous wave heights.

This is going to be absolutely astounding to watch as it evolves over the next 24-48hrs...

 

[Robert Dewey]

I think the "Superstorm of 2010" is a pretty appropriate title for this event, barring any significant changes (hell, they're already down to 983MB in central SD). Both the GFS and NAM are now in agreement that we'll be looking at a 955-960MB low, which would definitely be the strongest Great Lakes storm in [recorded] history. I'm not sure how I feel about the 1978 Superstorm being in the running, as it wasn't a typical "Great Lakes" storm... even so, this current event will be giving it a run for its money.

Both the GFS and NAM have been consistent over the past several days in spreading extremely strong surface winds across the region Wednesday, as mixing layer heights skyrocket toward 800-750MB. Within that layer, there's a pretty substantial wind maximum on the order of 60-80knts, pivoting through the region. Over MI, BUFKIT is showing 70-75knts at the very top of the mixing layer (highest magnitudes I've ever seen over this area), with 45-50knts easily being tapped into.

I suspect most of the high wind watch region [Dakotas to OH] to experience solid 50-60MPH winds as time progresses from late Tuesday through the day on Wednesday. I would not be at all surprised to see a few isolated locations report 80-100MPH gusts, particularly along lake shores susceptible to SW / W flows. The November 10th, 1998 storm produced several gusts of that magnitude.

 

[rdale]

I guess I'm missing the historic winter weather associated with this event... It doesn't seem like the cold surge will be enough for widespread blizzard conditions. Joel - where are you thinking the hardest hit areas will be? This seems more like a "fall" storm than a winter one.

 

[Mike Kovalchick]

http://www.glerl.noaa.gov/res/glcfs/glcfs.php?lake=l&ext=wv&type=F&hr=-1

Wave height animation of the Great Lakes..gotta love those 25 feet waves projected over Lake Superior!

 

[Ben Kossow]

Was just going to post that 31' waves are possible in Lake Superior. Would NOT want to be out on any of the western Great Lakes or Green Bay through about Wednesday.

And true...probably very limited winter weather, but the extended wind event should be pretty spectacular. Almost like a mid-level tropical storm, minus the warm temps.

 

[ahaberlie]

I was discussing this storm with a friend of mine and he brought up November 10, 1998 which brought a phenomenon called "stratospheric intrusion" where parts of the stratosphere are pulled to the surface, resulting in increased ozone levels in the troposphere and non-convective severe criteria winds (93 mph was recorded at ARX) Potentially, high risk groups (lung/respiratory issues) could be effected in isolated areas where this storm contributes to higher ozone levels at the surface.

 

[Mike Smith]

Have you looked at some of the local forecasts?

MSP: Winds could gust as high as 38 mph.

GRB: South southwest wind between 28 and 36 mph, with gusts as high as 50 mph.

FAR: Windy, with a west northwest wind 25 to 28 mph increasing to between 33 and 36 mph. Winds could gust as high as 55 mph.

I have posted the highest winds in their public forecasts. I believe these (among many others) are WAY too low.

I have a posting that might be of interest here: http://meteorologicalmusings.blogspot.com/2010/10/when-gales-of-november-come-early.html

 

[rdale]

I don't think Joel was implying that there's an impending blizzard...

I was just confused seeing it discussed in the winter section and assumed that's the path he was taking. He explained.

In any case, Chicago put out a nice list this morning:

NOUS43 KLOT 251533
PNSLOT

PUBLIC INFORMATION STATEMENT 
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1030 AM CDT MON OCT 25 2010

HOW THE UPCOMING CYCLONE RANKS AMONG OTHER NOTABLE CYCLONES OVER THE 
GREAT LAKES.  

RANK        EVENT             DATE          MINIMUM CENTRAL PRESSURE 

1.   GREAT OHIO BLIZZARD     1/26/1978          950 HPA /28.05 IN/

2.   UPCOMING EVENT         10/26-27/2010       959 HPA* /28.35 IN/

3.   ARMISTICE DAY STORM     11/11/1940         967 HPA /28.55 IN/
     ANNIVERSARY STORM       11/10/1998         967 HPA /28.55 IN/

4.   CYCLONE OF 1913         11/7-9/1913        968 HPA /28.60 IN/
    /AKA WHITE HURRICANE/   

5.   EDMUND FITZGERALD STORM  11/10/1975         980 HPA /28.95 IN/ 


*  AVERAGE AMONG SEVERAL CURRENT FORECAST MODELS 


$$
MERZLOCK

 

[Mark Sefried]

I chased the 10/24/2001 event along with Chris Novy. We managed to very briefly (about 4-5 seconds) view a rain wrapped tornado a little east of Monticello, IL in Piatt county. This event looks somewhat similar. I would strongly advise against anyone with little chasing experience to attempt to chase especially if it stays linear with embedded brief wrain wrapped tornadoes on the leading edge. The only way we could really tell the tornado was going to pass to our north visually was by the wind direction which increased rapdily from the SE to near 45 mph and we saw a rotating curtain of rain. More than likely that is all you are going to see if you get lucky. Even if I had the day off I would not be chasing this. Once the line hits ya there is no way you are going to stay ahead of it unless you are on an interstate that runs West to East.

 

[Robert Dewey]

Found a hi-res WRF run (5km) from NWSFO MQT, mainly centered across the northern Great Lakes. It pretty much sums up my thoughts on the convective aspect of this system. The system strength is slightly deeper (~2mb) than the NAM, but it shows healthier CAPE (750j/kg) with insane bulk 0-6km shear values of 100knts... & 70-80knts in the first KM!

 

[Robert Dewey]

NWS MQT's 5km WRF run is absolutely insane with pre-frontal winds... with sustained sfc barbs on the order of 35-40knts out of the SE & upwards of 50-60knts at 925mb. If that's the case, might even see high wind warning criteria gusts outside of convection.

 

[James Gustina]

This event looks somewhat similar. I would strongly advise against anyone with little chasing experience to attempt to chase especially if it stays linear with embedded brief wrain wrapped tornadoes on the leading edge. The only way we could really tell the tornado was going to pass to our north visually was by the wind direction which increased rapdily from the SE to near 45 mph and we saw a rotating curtain of rain. More than likely that is all you are going to see if you get lucky. Even if I had the day off I would not be chasing this. Once the line hits ya there is no way you are going to stay ahead of it unless you are on an interstate that runs West to East.

Agreed. The terrain is also not gonna help for the most part. Unless you're in central Indiana/Ohio it's gonna be hilly or full of trees or both. A similar setup from this year was June 15th. Fast moving squall line that produced some serious wind and may have had some brief tornadoes all up and down the line.

But on a forecast note, it looks like the NAM has it rolling through with the front around 5-6 in central Indiana/Ohio. Little area of instability popped up in central Indiana which might add a little fun to this thing with some insane speed shear.