Jan 17th-19th Rain/Snow/Mix/LES System

[jaster220]

Absolutely....tbh, this is turning out to be a very interesting storm. It will get very engrossing during the next couple of days.

 

Creeping up on a decent plowable snow followed by legit cold temps (shhh! don't want 'em to notice). 15/0z GFS gets mby to 6-7" by Sunday morning. Hopefully the warmth in the middle isn't as bad as Peeps are thinking it will be. 

[St Paul Storm]

GRR has put crap like that in my grid in recent winters. They need to go back to using "Light Snow" "Snow Showers" or "Flurries" like they used to do. Apparently that's too confusing or they think this hyper-reflex gen is just going to skip right to amounts so it doesn't matter. Idk but yeah, that's super lame

Looks like someone pressed the wrong button. The whole cwa has no accumulation on Friday night. That’s an obvious mistake. It should say 3-5” or 2-4” expected. Bad time to send out bad info.

[Grizzcoat]

CMC probably the coldest for 850's. Should be good for many on here.

[snowstorm83]

CMC looks to be the last one hanging on to a good front end thump for eastern Neb. Bless it's heart. 

[Niko]

Creeping up on a decent plowable snow followed by legit cold temps (shhh! don't want 'em to notice). 15/0z GFS gets mby to 6-7" by Sunday morning. Hopefully the warmth in the middle isn't as bad as Peeps are thinking it will be. 

I can definitely see us in the 4-8" range.

[Stormhunter87]

CMC looks to be the last one hanging on to a good front end thump for eastern Neb. Bless it's heart.

Sad is the day that I have to believe in the cmc. But who knows the Nam has been terrible lately.

[Grizzcoat]

Sad is the day that I have to believe in the cmc. But who knows the Nam has been terrible lately.

Yep- with the event last Friday the NAM and even 3KM NAM has double digits snows for my area. Ended up with 3-4".

[Grizzcoat]

NW IA does very good this run of EURO. (Compared to previous runs)

 

https://www.pivotalweather.com/model.php?rh=2020011500&fh=96&dpdt=&mc=&r=us_mw&p=sn10_acc&m=ecmwf_full

[Tom]

00z Euro...

 

 

[Tom]

00z Euro Control/EPS...

 

 

[Tom]

00z Canadian...

 

[james1976]

I like how its comin in colder from the west

[Grizzcoat]

The 06Z GFS is coming in warmer from the S. Might be good for N.IA and S.MN etc. but it's not looking good for E.NE and I-80 on E. Like I said days ago- not liking Mby for more than 3-4"

https://www.pivotalweather.com/model.php?rh=2020011506&fh=96&dpdt=&mc=&r=us_mw&p=snku_acc&m=gfs

[Grizzcoat]

DMX coming around to another 2-3" event for C.IA with rain on top. Not one to give in on a winter but as Randy Moss says--- "COME ON MAN". This is exactly what I thought would happen 48 hours ago. Things can change but running out of time. Riding the 850 0C line gets old. Congrats to those further N-- those East- I think you may be in line to what is going on in C.IA.

 

The major weather story of the forecast, and in some ways the
entire winter season so far, is the storm set to affect the region
from Friday into the weekend. Confidence has increased steadily
over the last several days regarding most aspects of this storm
and its sensible effects and impacts. Overall track and timing are
high confidence at this point, and QPF looks to be very high for a
storm of this nature at this point in mid-January, with most of
our forecast area looking at half to three quarters of an inch of
liquid-equivalent precipitation over the course of the event.
Precipitation will begin as snow, moving in Friday morning and
falling heavily for much of the day. Most of the area is looking
at nearly half an inch of QPF in the form of snow just during the
day Friday, which will rapidly accumulate to several inches over
most or all of our forecast area. However, strong low-level warm
air advection will push temperatures above freezing in southern
Iowa, limiting snow ratios and accumulation rates in the afternoon
but also making for sloppy travel conditions, while further north
colder temperatures will allow for higher accumulations and more
snow packing on roads and other surfaces. All in all it is fully
expected that travel will be difficult/hazardous across pretty
much all of Iowa for much of Friday, once the snow begins in any
given area.

By late in the day Friday an elevated warm layer, pushed up by the
aforementioned warm air advection, will cause precipitation-type
issues mainly in our southern and western counties initially,
which are exacerbated by temperatures potentially reaching the
mid-30s. This will likely result in snow turning to a mixed bag of
rain/freezing rain, however, precipitation rates will be easing by
that time and any ice accumulations should be limited. In
addition, any icing that does occur would come on top of freshly
deposited snow, greatly mitigating impacts. As we move into Friday
night the initial swath of warm advection and heavier
precipitation will move off to the east and a relative dry slot
will surge northward across the area. Forecast soundings indicate
the distinct possibility of a period of more widespread
drizzle/light rain with temperatures falling below freezing, so
additional light ice accumulations are forecast Friday night
though again, impacts will be mitigated by the underlying snow
cover. The above-freezing temperatures and precipitation-type
issues discussed herein are limiting factors on confidence
regarding snow amounts, especially across the
southern/southwestern half of the service area, while confidence
in snow amounts is somewhat higher further north/northeast where
these issues are much less prominent. In any event the entire
period from Friday through Friday night will be a mess and
widespread travel impacts are a near certainty.

[Tom]

06z GFS...

 

[james1976]

Yeah I just read DMX and was about to post it. Definitely C and SW Iowa could see mixing issues. Even up here we might see a period of rain/frz rain/drz but hopefully mainly snow. I like how we get another shot of snow on the backside with strong wind. Feeling pretty good up this way overall.

[james1976]

A bit more from DMX to add to what Grizzcoat posted. I like how they end the discussion:

 

Late Friday night/early Saturday morning the surface cyclone

parenting this winter storm system will finally move across Iowa,

and immediately on the backside of the low pressure center we will

see a renewed surge of cold advection snow, with lower QPF but

higher ratios and no more precipitation-type uncertainties.

Accompanying this second shot of lighter, but still accumulating

snowfall, will be strong northwest winds surging into the state

and persisting right through Saturday along with continuing light

snowfall/flurries. This will cause blowing snow issues, most

significantly while accumulating snow is still falling and in

areas that receive the highest preceding snow amounts. Blowing and

drifting of snow could be significant across the northern half or

so of Iowa and will cause continuing hazardous travel right

through Saturday.

 

The system and its snowfall will finally exit central Iowa late on

Saturday, though it will take some time for winds to diminish

Saturday night as a tight surface pressure gradient remains in

place ahead of a large, Arctic high pressure center building in

from the northwest. This high pressure will bring the coldest

temperatures of the winter so far to all of Iowa, made even colder

by the fresh snow cover and combining with the winds to send wind

chills plummeting to dangerous levels, especially across northern

Iowa, by Saturday night/Sunday. Bitter cold will then persist for

a couple days, with afternoon *high* temperatures on Sunday and

Monday peaking only in the single digits above zero in most areas.

Temperatures will likely moderate somewhat toward the middle of

next week, but confidence is low this far out. The good news, such

as it is, is that no precipitation is expected from the time the

winter storm exits late Saturday through at least Tuesday, so

during that time we will be dealing primarily with the cold and

with cleanup from the storm. No matter how you slice it...winter

is about to arrive with a bang on Friday, for those who do not

think it already has.

[Tom]

LOT's early take calling for 3-5" across the majority of the CWA...

 

 

 

Duration and snow ratios will be keys to this and right
now have a preliminary forecast of a couple inches southeast half
of the forecast area toward three to five in the northwest third
or so. This falls near the model solution mean from the 00Z suite
and WPC supports this as well, but still of course a decent
amount of uncertainty.

 

[dubuque473]

Sounding like 3-5” here, I can live with that.

[Tom]

06z NAM...

 

[Tom]

The trend over the last 24 hours are for this system to really deepen as it tracks towards the N GL's....possibly down into the 980's into the Mitt???  The back-side winds will be quite strong blowing the snow around and making it interesting for LES potential for our MI peeps.

[dubuque473]

Swails going with 5-6”. I sm guessing North of hwy 30.

[St Paul Storm]

MPX going 8-12” for now with gusts up to 35mph.

[Money]

Looks like 4-6/5-7 here

 

SPS looks golden

[Clinton]

6z Euro through hr90

[Clinton]

For KC it's looking like i over to rain.

[james1976]

Most models droppin 5-6 on me. That would be nice.

[dubuque473]

DVN just updated for 3-7” here.

[Stormhunter87]

OAX is really odd on their forecast. :/

[bud2380]

If I get 4" here I'd be pretty happy with that.  I'm concerned it will be more like 1-2" though.  Models are all over the place around Iowa City/CR for this one.  

[bud2380]

9z SREF plume average for CR is up to just over 4".  

[FV-Mike]

Would really like to see 3-5 inches out of this. We had a similar storm last year 1/18-1/19 right before the artic air came in. 

[East Dubzz]

NAM brings the SLP right through the area but keeps it mostly snow?? I'll believe it when I see it.

[Stormhunter87]

Hmm Nam much better for E. NE.

[jaster220]

06z GFS...

 

 

 

The trend over the last 24 hours are for this system to really deepen as it tracks towards the N GL's....possibly down into the 980's into the Mitt???  The back-side winds will be quite strong blowing the snow around and making it interesting for LES potential for our MI peeps.

 

I began to see that last night, thus the date tweak seemed even more appropriate. I think the 06z GFS is an improvement for me here due to that stronger backside with a little boost from the lake. (Actually, IWX's disco yesterday mentioned significant LES acccum's probable and not likely even reflected well by globals at this range). Could be interesting if we score 2-3" of cemented stuff followed by higher-ratio snows and winds. You know I like me some drifts and Marshall's got enough open farmland around to get some good ones going.    

[Niko]

Heavy snow in my forecast for Friday night into Saturday...... There will be a Neg-Tilt as this thing approaches MI.

[jaster220]

NAM brings the SLP right through the area but keeps it mostly snow?? I'll believe it when I see it.

 

It may be off on the final SLP location. But, we occasionally do get these front-side dump events that work out good even with the SLP over head or even NW (see Dec 2016 storm here)

[jaster220]

Heavy snow in my forecast for Friday night into Saturday...... There will be a Neg-Tilt as this thing approaches MI.

 

In your grid icons or txt only at this point?? 

[Niko]

NOAA:

Attention then turns to the well-advertised system slated to track
through this weekend. The parent longwave trough will move onshore
on the west coast Thursday afternoon and track steadily eastward,
reaching the Great Lakes with possibly a slight negative tilt by
Saturday night. With a midlevel ridge present over the western
Caribbean and SE CONUS, plenty of Gulf moisture will be directed
northward and fed into the system. Guidance has trended toward a
slower consensus with the start of precip starting late Friday. This
timing adds confidence that SE Michigan will experience a round of heavy
snow Friday night. A respectable amount of
moisture - pwats around 0.75 inches - will ride in on a 50 to 60 kt
low level jet and could lead to good snowfall rates and non-trivial
accumulations of snow across the area on Friday night.

 

This puts my area respectively in the 7-10inch range.

[jaster220]

From DMX

 

Precipitation will begin as snow, moving in Friday morning and falling heavily for much of the day.

 

Haven't seen that in months!  Hardly a dud in my book and would be welcomed sight for sore eyes