Nov. 25th-26th Midwest Snowstorm Potential

[CoalCityWxMan]

Wondering if LOT is about to pull the trigger on blizzard warnings..

[HillsdaleMIWeather]

IWX went for only a WWA for a few counties

[Hoosier]

No Blizzard Warning from DVN, at least for now.

[Hoosier]

26 minutes ago, Jackstraw said:

The Halloween storm of 2014 that LOT is alluding to concerning flooding didn't have the winter stuff going on with it did it?  Not familiar enough but I would think if this pans out could get messy.

There was a little lake effect precip but nothing like this storm.

[RyanDe680]

National Weather Service Chicago/Romeoville, IL
320 AM CST Sun Nov 25 2018

.SHORT TERM...
320 AM CST

Today through Monday...

Powerhouse early-season winter storm taking aim on the region
later today and tonight. Travel conditions are expected to become
hazardous and potentially life-threatening across parts of
northern Illinois, as a combination of intense heavy wet snowfall
and 45 mph winds produce snow covered roads, blowing and drifting,
and poor visibility. Winter Storm Warnings and advisories remain
largely unchanged in coverage, though have pushed start/end times
back a few hours in some cases based on consistent model trend of
a slower storm system. In addition, new Winter Weather Advisory
headlines are in place for Lake and Porter counties in northwest
Indiana later tonight, and Lakeshore Flood Warning has been
extended into Lake County IL (see separate paragraph at end of
discussion). Total snowfall amounts in the 8-12+ inch range are
expected across north central and portions of northeast IL, with a
amounts dropping off quickly along the I-55 corridor eastward.

Vigorous mid-level short wave was evident across the western
Plains in early morning water vapor imagery. Associated 995 mb
surface low was analyzed near Wichita Kansas as of 08Z/2 AM CST.
00Z guidance in pretty good agreement in tracking this low to near
St. Louis by this evening, then east-northeast to the Champaign
IL/Lafayette IN area by midnight tonight. National radar mosaic
depicts a west to east oriented band of precipitation developing
from southeast Nebraska into southwest Iowa, where low level
cyclonic flow was inducing warm/moist advection and ascent in
response to the short wave. The resulting tightening of the
elevated baroclinic zone (frontogenesis) is progged to extend
eastward into northern IL by mid-morning, producing a region of
banded precipitation along and north of I-88 across northern IL.
Forecast soundings depict an above freezing layer between 900-800
mb, which will likely result in precipitation initially falling as
a mix of rain/snow in this west-east band this morning/midday. As
large scale forcing for ascent increases early this afternoon
with the approach of the short wave, wet-bulb and dynamic cooling
is expected to cool the column enough to change precipitation over
to all snow across north central Illinois. Farther east,
precipitation is expected to begin primarily as rain,
transitioning to rain/snow and then all snow into this evening.

Snowfall is expected to intensify across north central IL late
this afternoon, as moist ascent strengthens in response to
increasing vorticity advection, very strong mid-level
frontogenesis, steep mid-level lapse rates, and strong upper level
divergence associated with coupled left front/right rear jet
streak regions. Various explicit model guidance and high-res
ensemble statistical output indicate the potential for snowfall
rates of 1-2 inches per hour, persisting across a good portion of
northern Illinois through the evening hours. During the same
period, the tightening of the surface pressure gradient north of
the low track will result in northeast winds increasing to near 30
mph, with gusts to 45 mph likely. The combination of heavy
snowfall and very strong gusty winds will undoubtedly produce
rapidly deteriorating travel conditions, which may very well
become life-threatening due to poor visibility in heavy falling
snow and blowing and drifting. In addition, the combination of
very heavy wet snow and strong winds may result falling tree limbs
and power outages. Near white-out conditions will be possible,
and an upgrade to Blizzard Warnings is not out of the question
later today, though in collaboration with surrounding WFO`s we
elected to allow day shifts to make that call depending on how the
storm develops. The strong deformation band and most intense
snowfall gradually shifts from west to east across the forecast
area through late this evening, eventually moving east of the area
early Monday morning. This will allow snowfall to taper off and
end across north central IL prior to daybreak, and shortly
thereafter in the east. The exception will be across northwest
Indiana, where lake effect snow showers may persist during the
morning. As indicated in the first paragraph above, total snowfall
is expected to range from 8-12+ inches across much of north
central and far northeast IL, with amounts quickly dropping off
near the I-55 corridor and areas south and east. Winter storm
warnings are in effect generally for areas in the 6+ inch amounts,
with winter weather advisories farther southeast where 2-5 inch
amounts are expected.

Snow will taper off quickly across the east Monday morning, with
a few snow showers lingering through perhaps midday for Lake and
Porter counties in northwest Indiana. Winds will gradually
diminish and turn more west-northwesterly by afternoon. It will be
chilly with highs only in the mid 20s to low 30s, and wind chills
in the teens.

[ILwxchr]

In the Quad Cities area for this event. My call for the cities is going to be 10-12"+ of snow with wind gusts possibly approaching 50 mph later tonight. I might have to drop south this evening if the HRRR is correct in showing 54 knot wind gusts (62 mph). IMBY I'm expecting around 7-9" with 50+ mph wind gusts. Totals won't make much of a difference though with that type of wind. I visited the NWS in Quad Cities this evening and they told me the criteria for blizzard warnings is very strict (which we know that), that call will be made later today once the storm starts to evolve toward the county warning area. Don't want to issue a high end product (Blizzard Warning is the most serious product they issue, per NWS), and have to revert to a lower product if it doesn't pan out. Public reception isn't very good when it comes to changing weather data. Although looking at the 06z data, its looking like it will be needed at some point (blizzard warnings). If this pans out, it will make my top 5 list for sure. Have fun everyone and be safe.

[Scud]

Yea, this is a big deal.

54 minutes ago, ILwxchr said:

In the Quad Cities area for this event. My call for the cities is going to be 10-12"+ of snow with wind gusts possibly approaching 50 mph later tonight. I might have to drop south this evening if the HRRR is correct in showing 54 knot wind gusts (62 mph). IMBY I'm expecting around 7-9" with 50+ mph wind gusts. Totals won't make much of a difference though with that type of wind. I visited the NWS in Quad Cities this evening and they told me the criteria for blizzard warnings is very strict (which we know that), that call will be made later today once the storm starts to evolve toward the county warning area. Don't want to issue a high end product (Blizzard Warning is the most serious product they issue, per NWS), and have to revert to a lower product if it doesn't pan out. Public reception isn't very good when it comes to changing weather data. Although looking at the 06z data, its looking like it will be needed at some point (blizzard warnings). If this pans out, it will make my top 5 list for sure. Have fun everyone and be safe.

Yea, this is a big deal.

[King James]

Two counties south of Chicago and I’m looking at 2 inches. Hoping for a surprise a little SE (like 15 miles is all I need) to get us higher totals. Buddy is Naperville text me last night he thinks he’s going to get 2-3 inches, hadn’t looked cause he was decorating, nice little holiday surprise for him. Enjoy the show boys.


.

[weatherbo]

[weatherbo]

[OceanStWx]

2 hours ago, ILwxchr said:

In the Quad Cities area for this event. My call for the cities is going to be 10-12"+ of snow with wind gusts possibly approaching 50 mph later tonight. I might have to drop south this evening if the HRRR is correct in showing 54 knot wind gusts (62 mph). IMBY I'm expecting around 7-9" with 50+ mph wind gusts. Totals won't make much of a difference though with that type of wind. I visited the NWS in Quad Cities this evening and they told me the criteria for blizzard warnings is very strict (which we know that), that call will be made later today once the storm starts to evolve toward the county warning area. Don't want to issue a high end product (Blizzard Warning is the most serious product they issue, per NWS), and have to revert to a lower product if it doesn't pan out. Public reception isn't very good when it comes to changing weather data. Although looking at the 06z data, its looking like it will be needed at some point (blizzard warnings). If this pans out, it will make my top 5 list for sure. Have fun everyone and be safe.

This is a case more akin to what I normally deal with on the East Coast now. You need the heavy snow to be falling at the same time you get the gusty winds. Normally the snow is quite dry and even after the heavy snow stops the winds can blow it around to reduce visibility to 1/4SM. This is a case of wet snow that won't blow around as easily during the height of it, so there is a little more caution than normal for a blizzard warning.

Right now the HRRR has the best juxtaposition of low visibility and high winds across N MO and far SE IA.

[Radtechwxman]

Euro's consistency is pretty remarkable. Def can't be ignored. Seems like models finally honed in on a low track near I70. Slightly better for my area. Blizzard conditions are looking pretty set in stone with 40-50+ gusts coinciding with an insane deformation band. Only thing that may keep blizzard warnings from being issued would be the time criteria needed but I still think DVN and LOT and nw portion of ILX need to upgrade. This is going to be high impact for hours. Looks like my snow will all be after dark which will be good for better ratios. Mon morning commute is going to be treacherous for many

[OceanStWx]

The HRRR and NAM 3km seem to have a pretty good handle on the simulated reflectivity at the moment. Just showing you how difficult the forecast is, the NAM has a range of 0 to 10" across Johnson County, IA.

But given the sharp northern edge to the precip shield right now, it's entire possible we get that kind of gradient.

[Jonbo]

16 hours ago, Jonbo said:

Slice a knife across Des Moines with these totals each run... I'll assume the worst, wouldn't take much going north or south to drastically change amounts IMBY at this rate.

The knife guess was too accurate

[OceanStWx]

The radar seems to be a fair match for 700 mb f-gen at the moment too. The near term forecasts are for that to increase in place (not really moving north or south too much), so if you're under the band now that's good news.

[King James]

The knife guess was too accurate

Gross


.

[RobertSul]

11 minutes ago, Jonbo said:

The knife guess was too accurate

 

My deepest condolences. 

[Jonbo]

8 minutes ago, OceanStWx said:

The radar seems to be a fair match for 700 mb f-gen at the moment too. The near term forecasts are for that to increase in place (not really moving north or south too much), so if you're under the band now that's good news.

Definitely increasing around/over Osceola, IA. Northern edge is retreating south a little but southern edge picking up

[UMB WX]

hrrr was uglllyyy for MKE.  Storms just don't cut up in to MI anymore.

[ILSNOW]

 

 

[mimillman]

12z NAM a lot more generous on the southern end.

[miamarsden8]

So down in Macomb, it's a pretty big travel day. I'm really worried about the travelers heading back here and to other schools.

 

But! Given the nws's forecast...they're calling 3 inches right now...I'm really hoping that's too low. I've never gotten to see a legitimate blizzard in my lifetime. I hope this thing shifts just a bit further south. If it doesn't, I'll be sad, as it seems we miss all the good storms.

 

Edit: The Euro's got me sitting at 8-12...and the Euro's usually good at snow...Come on baby! Just a bit further south!

 

[hawkeye_wx]

Cyclone should get in on the good snow, but the dry air is going to win along and north of Des Moines to Cedar Rapids.  I'm not expecting anything now.

[ILwxchr]

Heavy rain here in the QCA. Sitting at 36 degrees. Should start cooling off soon, we have a pretty strong band that is E/W almost stationary. Hopefully we can get some dynamic cooling to switch over to snow by 11am or so, which is what the HRRR was indicating earlier.

[homedis]

Rain mixed with some sleet/graupel in Northbrook currently.

[OrdIowPitMsp]

Congratulations to everyone getting significant snowfall today! This has been a fun storm to track, and lurk on these forums while things evolved. 

My brother is sitting in Des Moines losing his mind as the system slides just south of him. Nothing but flurries where he’s at. 

Meanwhile up here in Minnesota it is cold and dry....at least the sun is poking out and will let me finish getting the yard ready for winter. 

[OceanStWx]

27 minutes ago, ILwxchr said:

Heavy rain here in the QCA. Sitting at 36 degrees. Should start cooling off soon, we have a pretty strong band that is E/W almost stationary. Hopefully we can get some dynamic cooling to switch over to snow by 11am or so, which is what the HRRR was indicating earlier.

The 14z RAP shows a quick cooling between 18 and 19z as mid level winds turn E instead of SE, flipping DVN to all snow. 

[janetjanet998]

29 minutes ago, ILwxchr said:

Heavy rain here in the QCA. Sitting at 36 degrees. Should start cooling off soon, we have a pretty strong band that is E/W almost stationary. Hopefully we can get some dynamic cooling to switch over to snow by 11am or so, which is what the HRRR was indicating earlier.

That band (the most intense part at least) seems to be inching north....and by the time it changes  to snow it may be north of you (QC)...just a tad more cold air and it would be snow already...

I think, my area, Peoria will be upgraded to warning....heavy snow rates and wind gust to 50 MPH  in deformation  band this  evening

 

[miamarsden8]

The Euro 12z run will be very telling, I think. But honestly, I'm rooting for y'all in Chicago and Peoria to get your southeast shift. Any southeast shift is a good shift.

[Natester]

I wouldn't be surprised if the low tracks south of forecast.  If we do get anything, it'll likely only be an inch at most.  As terms of potential power outages, I don't have to worry about that since we won't get much.