11/30/2006 FCST: IL / MI / IL / MO / KS / OK (WINTER PRECIP)

[Robert Dewey]

does that put it through chi town or just south like kankakee??? TWC says an inch of ice for chi town im not buying into that, its 21 degrees in omaha and its heading in our direction.....i cant imagine freezing rain for too long before snow????

SFC T's don't dictate rain or snow - it's what's going on upstairs. LOT is all snow on all of the models EXCEPT for the FSL RUC. The FSL RUC has a 984MB low tracking just west of Chicago, giving much of IA and MO the heaviest snow (it's outputting 18-24 inches). Right now, I'm going to say snow for northern IL, how much remains to be seen.

 

[Brett Roberts]

It appears as though OUN is going to upgrade the WWA to a WSW for Thursday. Their snowfall forecasts seem a little out there to me, but then, they may be seeing something I'm not that would lead them to believe 4-12 inches of snow is likely across Oklahoma...

Not that taking model QPF at face value is ever a wise thing, but at 12z both the GFS and NAM are painting greater than 0.50" liquid amounts over most of the eastern two-thirds of the state for tonight through tomorrow. With the trend towards the upper-low closing off earlier and moving out slower, I don't think those numbers seem particularly outrageous. I think they're expecting mesoscale banding to provide the higher > 8" amounts.

 

[Danny Neal]

just heard from NWS Chi-Town winter storm watch imminent for tomorrow night into friday system looking better organized, if low develops in texas chicago-peoria-quad cities-and points east can be in for significant accumulations

 

[rdale]

Daniel - check Jeff Snyder's post above... We all know how to read NWS forecasts, this forum is for people to give their own interpretations (or at least reasons why they agree with the NWS.)

 

[Danny Neal]

that is my interpretation of what i have heard first hand from the spotter network in direct contact with NWS Chicago before any watches or warnings were issued by 6 pm tonight a WSW will be issued for the counties of chicago and surrounding areas, and my forecast is that if the low develops in texas and continues on its current track that most models are showing that places east to where i mentioned will be in significant storm accumulations....i see no fault in that, im merely stating what we spotters in chicago are discussing and what i feel will happen, in total compliance of the rules

 

[Robert Dewey]

12Z WRF's starting to roll in. The most interesting is the FSL RUC that takes a 985MB low west of Chicago with much of IL getting rained out - I believe this is way out of line.

All of the other WRF models are in line with the GFS, UKMET, and GEM models in terms of the storm track... So now it's the NAM versus GFS/UKMET/GEM, I guess we'll still have to wait and see what future model runs show (obviously).

Here are the model tracks:

http://www.emc.ncep.noaa.gov/gmb/tpm/emchurr/tcgen/tcgif/track.all.2006112912.east_coast.single.gif

And the SREF members:

http://www.emc.ncep.noaa.gov/gmb/tp...rack.srperts.2006112909.east_coast.single.gif

The operational NAM takes the low into extreme southwest Ontario, which deviates quite a bit from what the other members are saying (and the other set of models). I can also see the ensemble that the FSL RUC is running on (the 984MB low west of Chicago).

 

[Joel Wright]

These models are about to make me lose my mind. Anyway, obviously as you all can see the trend is to evolve a stronger low on a further westward track, sort of where it had it forecast two nights back. I'm not sure why the models did that slow oscillation like that, but nevertheless they are back to what they originally suggested.

Even with the event 30-40hrs away I still have basically no confidence in the exact track. Since the band of heavy snow appears to be relatively narrow, that only compounds the problem lol.

For whoever ends up in this band of heavy snow, they will likely see a very heavy burst of snow at some point, probably with some lightning flashes as well just by looking at the intensity of the deformation band and UVV's.

Hopefully the next few runs finally settle on a stable solution, but even then I won't be 100% convinced until I see the evolution of things on radar tomorrow...

 

[Robert Dewey]

Well, the 18Z NAM is even further west - mostly rain for much of IL. If the trend continues, the FSL RUC might not be too far off, LOL.

18Z GFS continues the trend...

General area of heavy snow appears to be from OK all the way into the western half of lower MI (LAN westward), with the heaviest axis centered across MO and IL. Whoever gets stuck under the heaviest band would likely see +18 inches. That's my current thought as the model trend is definitely westward. Wouldn't be surprised to see the heaviest action pushed into MO and IA, in line with what the models originally showed a few days ago (before flip-flopping).

 

[Robert Dewey]

Latest 00Z NAM starting to roll in... The 00Z analysis already has the 500MB system starting to close off, but not as deep as the 12Z... I'll edit this post as soon as the rest of the NAM data is in.

 

[Brandon Sullivan]

Rain continues to fall and slowly mix with sleet. Question for rdewey. Do you really think that the heaviest band could shift that far west? I have seen the models and did notice a trend to the west. But you know what your talking about and I was just wondering. I do see the potential for the 8-12 inches based on the 00Z nam. Temp free for all started a little earlier than i think anyone was anticipating. with an earlier passage of the front than expected as well.

 

[Robert Dewey]

Rain continues to fall and slowly mix with sleet. Question for rdewey. Do you really think that the heaviest band could shift that far west? I have seen the models and did notice a trend to the west. But you know what your talking about and I was just wondering. I do see the potential for the 8-12 inches based on the 00Z nam. Temp free for all started a little earlier than i think anyone was anticipating. with an earlier passage of the front than expected as well.

Looks more like most of MO, extreme southeastern IA, and northwest IL will get the best action based on the new NAM. The 00Z continues the westward trend... Looks like most of southern MI will be rain, and I suspect the watches can be dropped in favor of advisories.

The RGEM is also rolling in and continues the trend, as does the NGM. I think it's safe to say that IN and MI are probably out of the woods -- although there still appears to be a shallow layer of sub freezing T's at the SFC, at least up until FRI afternoon. That could provide for a quick advisory type of icing, but I don't see much more than that happening with the current models...

Anyway, NAM output across MO is beyond incredible... I see a max of 41 inches embedded within a very widespread area of 30-40 inches. The NAM QPF is probably overdone by quite a bit, but even using the GFS would produce solid 18-24 inch totals. MO looks like it's going to get hammered bigtime with this one, as does northwestern IL. A few ST members will be measuring snow by the foot or yard stick.

 

[Joel Wright]

Yeah it looks like north-central MO is going to see a lot of snow. I think the NAM is overdoing the amounts as Robert said. Even with that, a pretty respectable first snow to say the least for the midwest.

Chicago is looking to have a very tricky forecast. They will be pretty close to the rain/snow line, and add the complication of a warm Great Lake nearby and it gets worse.

I think the westward moving trend of the models is completed. The models have a decent hold on this system it appears now. Well, at least lets hope. I doubt the surface low will be any stronger than what is being forecast, and the shortwaves should be sampled well enough now that the computers should be more stable with this storm forecast.

One interesting note, the NAM and NGM seem to have slowed the storm just a bit this last run. If that trend continues amounts could be even higher in the heavy band...

 

[Matthew Havin]

Reporting from STL here........ looks like we are under a nightmare scenario here with the mix precipitation we will get on Thursday. A solid 12-18" snow band from north central MO into west central IL is possible, with higher amounts. We will be seeing a lot less snow here in STL, maybe in that 3-6" range, but ice accumulation is going to take a toll on the area......with some of the local yokels calling for a solid 1/2 inch of ice.

Ouch! Be prepared people!

 

[Brandon Sullivan]

thanks robert. when you say the watches can be dropped, you are referring to southern MI right? I do agree with the westward trend. its 9:44, 33 F and drops on the window beginning to sound icy. Based on what you are saying, it looks like i could be in a hard hit spot. Im 2-counties east of the IA MO border at the mississippi river.

 

[Danny Neal]

http://www.hpc.ncep.noaa.gov/wwd/day1_psnow_gt_04.gif


http://www.hpc.ncep.noaa.gov/wwd/day2_psnow_gt_04.gif 4+

really interesting this current track will give the heart of chicago the brunt of the heavy snow

http://www.hpc.ncep.noaa.gov/wwd/day2_psnow_gt_08.gif 8+

http://www.hpc.ncep.noaa.gov/wwd/day2_psnow_gt_12.gif 12 +

right now just a cooooold rain

freezing rain outlook

http://www.hpc.ncep.noaa.gov/wwd/day2_pice_gt_25.gif

this is interesting, the people ive talked to over the summer said this could be a warmer than normal winter with the most interesting weather starting in december and if i do say so myself they are right on target!

ill get my chance for my thundersnow experiment tomorrow night into friday hehe

ill save the trouble from getting ragged on so ill do it myself and move it here