12/16 - 12/18 Plains/Lakes Major Winter Storm

[Niko]

The GOM is wide open for business with this run.

Big time.....I think this storm will provide more moisture then the previous storm we just had.

[jaster220]

Big time.....I think this storm will provide more moisture then the previous storm we just had.

 

Yeah, earlier runs were touting 2X as much, so do the math..

 

Let me clarify that. The hardest hit areas look to have a shot at a 20" Big Dog, vs the 10 incher we just did 2 days ago. Now we just need to reel that portion of the storm into SMI and all's good 

[Niko]

Yeah, earlier runs were touting 2X as much, so do the math..

Question here is, will this continue??!!

[Niko]

Yeah, earlier runs were touting 2X as much, so do the math..

 

Let me clarify that. The hardest hit areas look to have a shot at a 20" Big Dog, vs the 10 incher we just did 2 days ago. Now we just need to reel that portion of the storm into SMI and all's good 

That's our goal with this storm.

[FV-Mike]

Here is IWX thoughts in their afternoon afd

 

"Good large scale consensus signals of
intensifying surface cyclone developing over the srn plains late Fri
which then ejects ne through the srn lakes Sat. Sfc low tracking
nwwd somewhere through IL/IN and then into MI will allow intense low
level thermal advection within expanding warm sector to obliterate
prior arctic dome late Fri night into Sat am. However prior to that
occurring deep/moist slantwise ascent within retreating arctic wedge
promises initial heavy snowfall Fri evening followed by mixing to
brief sleet/freezing rain and then even rain as sfc temps crawl
above freezing for a time Sat. Transition timing at this range
remains uncertain though with notable spread in how fast arctic
dome erodes. Signal trends not surprising with colder look in most
guidance Fri evening and slower ptype transition Sat am. Thus
suspect some significant snow accums likely early followed by a
period of icing. Regardless warm sector emergence looks both
shallow and brief as progressive cyclone aloft wraps quickly newd
and will wrap strong low level cold advection wing east in its
wake Sat aftn-evening with renewed snow chances. Further residual
moist cyclonic flow aloft and rapid veering nwrly low level flow
will undoubtedly yield a period of intense lake enhance snow Sat
night before transitioning to dwindling lake effect shsn Sun"

[Tom]

18z NAM through the end of run...

[winterfreak]

Yikes NAM is not good it looks like. At least out to 84hr.

[Tom]

Second half of Friday night rush hour looks impacting around here...I bet if this continues, ppl will want to leave work early.

[Tom]

18z NAM pushing the 0C isotherm line the farthest south of the bunch...usually its amped and farthest north...the HP then squeezes the system and a SLP forms just S of KC...

 

http://www.tropicaltidbits.com/analysis/models/namconus/2016121318/namconus_mslpa_us_53.png

 

http://www.tropicaltidbits.com/analysis/models/namconus/2016121318/namconus_T850_us_53.png

 

 

 

 

http://www.tropicaltidbits.com/analysis/models/gfs/2016121312/gfs_T850_us_16.png

[Tom]

18z NAM might be catching onto a SE flow off LM so folks from MKE on north towards Sheboygan may get some Lehs...

 

http://www.tropicaltidbits.com/analysis/models/namconus/2016121318/namconus_mslp_wind_ncus_53.png

[james1976]

Wow NAM. And thats only thru midnight Friday night.

[Tom]

12z GFS Para...10:1 ratios

 

http://www.tropicaltidbits.com/analysis/models/gfsp/2016121312/gfsp_asnow_us_21.png

[East Dubzz]

12z GFS Para...10:1 ratios

 

Ayeeee lock it in!

[Tom]

12z GEPS...took a tick south it seems...or maintains the southerly solution out of the global models...

 

http://www.tropicaltidbits.com/analysis/models/gem-ens/2016121312/gem-ememb_lowlocs_us_15.png

 

http://www.tropicaltidbits.com/analysis/models/gem-ens/2016121312/gem-ens_apcpn24_us_11.png

 

 

http://www.tropicaltidbits.com/analysis/models/gem-ens/2016121312/gem-ememb_lowlocs_us_17.png

 

http://www.tropicaltidbits.com/analysis/models/gem-ens/2016121312/gem-ens_apcpn24_us_13.png

 

 

http://www.tropicaltidbits.com/analysis/models/gem-ens/2016121312/gem-ememb_lowlocs_us_18.png

 

http://www.tropicaltidbits.com/analysis/models/gem-ens/2016121312/gem-ens_apcpn24_us_14.png

 

 

http://www.tropicaltidbits.com/analysis/models/gem-ens/2016121312/gem-ens_apcpn_us_21.png

[Tom]

12z EPS...similar to the bunch...nearly all of the ensembles are now cutting the low through S/C IL...

 

http://www.tropicaltidbits.com/analysis/models/ecmwf-ens/2016121312/ecmwf-ens_T850_mslp_us_4.png

 

http://www.tropicaltidbits.com/analysis/models/ecmwf-ens/2016121312/ecmwf-ens_T850_mslp_us_5.png

[Tom]

@ Okwx, how do the EPS snow maps look for this system???

[indianajohn]

Cool dude......Chios! What about you?

Pelopeonnese town called Astros about 1.5 hours SW of Athens. My brothers wife is from Chios he was there this summer they left right before the Fires started down there.

[NEJeremy]

The GOM is wide open for business with this run.

Actually this is almost entirely Pacific moisture. If this had Gulf moisture too than that would be even that much better! Take a look at the 850 streamlines and you can see where the moisture is coming from.

At the end of the 18Z NAM run the trajectories do show the moisture making it towards Ohio early Saturday morning.

[Tony]

Actually this is almost entirely Pacific moisture. If this had Gulf moisture too than that would be even that much better! Take a look at the 850 streamlines and you can see where the moisture is coming from.

At the end of the 18Z NAM run the trajectories do show the moisture making it towards Ohio early Saturday morning.

If you look at the 18z 12k NAM run you can see where GOM moisture is getting entrained into the system as well as the Pacific.

[FV-Mike]

Southern wisc looks really good right now

[NEJeremy]

If you look at the 18z 12k NAM run you can see where GOM moisture is getting entrained into the system as well as the Pacific.

Those are pressure lines in that map you showed, not streamlines showing where the moisture is coming from. If you match up our maps where mine shows moisture at 850 for example, you can see there is gulf moisture in the deep south which is where your map shows some light showers, but the trajectories at that time are taking it to the Ohio Valley. You have to follow the streamlines to see where the source. There is some very shallow moisture that makes it up earlier from the Gulf(925mb), but the main source is the Pacific. By the time the Gulf opens up where the deeper moisture makes it north, it's not until further east

[Tom]

18z GFS...

[winterfreak]

Might need to break out the shorts for this one.

[NEJeremy]

the 18Z GFS really crapped out the secondary band on Saturday.

[hlcater]

Gross.

[CentralNebWeather]

The towel is about to be thrown. 18z horrible run. It just gets worse and worse. Along with 12z looks like our brown December to forget continues. Canadian was no better and euro nothing to write home about.

[gosaints]

the 18Z GFS really crapped out the secondary band on Saturday.

This looks like it could be waa or bust

[Tom]

LOT's thinking...

 

 

 

Friday through Tuesday...

The main concerns are:
* Potentially significant winter system Friday through Saturday,
with mixed precipitation type concerns.
* Another blast of bitterly cold air in the wake of this system
Saturday night through Sunday night.

An extremely impressive lower level thermal gradient/baroclinic
zone will exist across the Plains on Thursday into Friday. At the
mid and upper levels, piece of PV bringing us the bitterly cold
weather this week will dive southward toward northern New England
and the Canadian Maritimes. At the same time, multiple shortwave
disturbances will come ashore onto the west coast and then carve
out a positively tilted trough over the Intermountain West. This
will result in rapid height rises into the Midwest, along with
very strong warm advection out ahead of surface cyclone that will
develop over the Plains. Associated strong isentropic ascent and a
lead shortwave will likely cause a band of moderate to locally
heavy snow to break out Friday across the region. The main
uncertainty is the positioning of the most focused forcing of the
lead shortwave Friday afternoon, with large implications on
snowfall amounts and impacts to the busy Friday afternoon/evening
commute.

The 12z operational GFS model, as well as recent NAM runs,
indicate that the lead wave will move right across northern
Illinois, favoring areas north of I-80 for potentially significant
snow accumulations (6"+ in less than 12 hours). Initial snow will
be high ratio given cold air temperatures and strong lift co-
located with a ~100 mb deep snow growth zone. On the other hand,
the foreign guidance, particularly recent runs of the ECMWF, is a
bit slower and focuses the lead wave into Wisconsin. This means
that while some light snow is probable mainly along/north of I-88
Friday afternoon/early evening, impacts would be much less. Given
the uncertainty and resulting lower confidence, capped PoPs at
likely north of I-80.

Moving into Friday night through Saturday evening, uncertainty
continues with the overall evolution of the mid-upper system,
associated surface low, as well as lower level thermal profiles.
Until the parent shortwave(s) move ashore Wednesday night through
Thursday for sampling by the RAOB network, confidence is too low
to make a call either way on this. While the cold dense Arctic air
mass in place to start the period certainly does not preclude a
surface low track cutting over the area, still wonder if the
system will be forced a bit southeast of some of the more wrapped
up operational and ensemble solutions, resulting in mainly a
snowier outcome for areas north of I-80.

With this being said, the warm advection surge in advance of the
surface low will continue to provide an impressive air mass
exchange, with enough warming aloft to possibly result in
precipitation type concerns creeping in from the south after
midnight Friday night. This includes the possibility of freezing
rain and sleet along/south of I-88. On Saturday, boundary layer
warming will likely be enough for a change to plain rain in east
central Illinois and along/south of the Kankakee River in Indiana.
Much colder air will then sweep across the area Saturday afternoon
behind the system, transitioning any mixed precipitation back to
snow by Saturday evening. If the slower ECMWF comes closer to
verifying Saturday night, will need to raise PoPs from current
forecast to account for system`s deformation axis pivoting across
the area and providing at least light snow accums area wide. This
would occur as a ~1040 mb high spreads southeast from the Northern
Plains, so increasingly windy conditions and blowing/drifting snow
could also be an issue Saturday evening and night.

[Money]

Chicago special

[GDR]

[CentralNebWeather]

It is to point that we actually see snow falling from the sky to believe any model around here.

[gosaints]

Chicago special

Reverse psych?

[CentralNebWeather]

Reverse psych?

Blizzard warning for all of Nebraska. Does that work for reverse psych?

[Tom]

Wait till it's sampled by Thursday and I'll be excited then if trends continue

[hlcater]

Chicago keeps on winning. That's the irritating part. Kinda feeling the burn of last system where we were forecasted 5-8" by the NWS and came out of it with nothing to show. We still don't have it nearly as bad as the Nebraskans however.

[Money]

Reverse psych?

Unless the thing wraps up I think a SE trend is likely to continue because of the arctic airmass in place

 

We are still good for 6-10 or so tho with the WAA snows

[gosaints]

Unless the thing wraps up I think a SE trend is likely to continue because of the arctic airmass in place

 

We are still good for 6-10 or so tho with the WAA snows

Gotcha I agree on the second part. Unless it wraps up I think the 2nd piece could be underwhelming

[CentralNebWeather]

Positive news: no snow to move, no slipping on the ice, drivers can drive normally. Who am I kidding, I want some snow for Christmas.

[FV-Mike]

Chicago keeps on winning. That's the irritating part. Kinda feeling the burn of last system where we were forecasted 5-8" by the NWS and came out of it with nothing to show. We still don't have it nearly as bad as the Nebraskans however.

Thought your area did better but saw Cedar Rapids official was 3.1 for the last storm. I remember when I was at university of Iowa it seemed that the amped up storms always were already east of IC

[NEJeremy]

Positive news: no snow to move, no slipping on the ice, drivers can drive normally. Who am I kidding, I want some snow for Christmas.

The other thing is we stay out of the absolute deep freeze. I love snow, but HATE the brutal cold!