Winter Storm - February 11-13, 2019

[AppsRunner]

Pretty good agreement between the UKMET/GEM/ECM across Iowa into E MN/W WI with a swath of 0.5-1.25" of QPF stretching from southwest Iowa up to La Crosse or so. Seems if any storm is going to be the big one of the season for DSM/LSE it'd be this one. 

[Hoosier]

18z NAM looks like it will up the ice potential.  Warmer aloft in more of northern IL.

[ILSNOW]

18Z NAM thru 66 10:1 ratio

 

[Ottawa Blizzard]

2 hours ago, snowstormcanuck said:

Right now I'd go with 4-8" for mby, given the fact we'll probably go over to some sort of mixture.  GEM and EURO though basically lock us in as snow beginning to end, but not ready to buy that yet.

Regardless, have to admit that this is one of the better snow seasons we've had this decade.

[ILSNOW]

LOT UPDATE

 

Monday night: A combo of WAA, the approaching mid-level trough, and
the left-exit of an upper jet should allow for a widespread swath of
moderate precip to shift NE across the CWA during the night. The
increased low-level WAA should push the surface freezing line to
along the I-80 corridor, thus ending the threat of freezing rain
south. Between the I-80 and I-88 corridors, including Chicago, the
dominate precip type looks to be freezing rain, whereas precip
should remain snow generally north of I-88. Given thermo profiles
only slightly below freezing below 700 hPa to the north, expectation
is for any snow to be fairly wet, with potentially <10:1 SLRs.
Lastly, east winds may gust as high as 30 mph through the night
across the north half of the CWA.

Tuesday: The surface low will track NE across the southern CWA into
NW Indiana during the morning. CAA will ensure, changing rain to
snow from NW to SE across the CWA through the day. Snow
accumulations during the day will range from 1-2" north to around a
half inch south. Meanwhile, NW winds will quickly increase with
gusts to 35 mph by sunset Tuesday across much of the area. Given the
wet snow potential, blowing snow does not appear to be a significant
issue at this time.

Headlines: First, have decided to hold off on any Winter Storm
Watches at this time. Had considered one for the northern tier of
counties plus Ogle county. Warning criteria of 6"/12hr or 8"/24hr
will likely not be met given the low snow ratios. However, impacts
from the very wet snow may ultimately justify the need for a warning
if guidance continues to indicate higher QPF over 0.5". However,
confidence is quite high that solid advisory-level snow will be met
across the northern tier of counties Monday evening into Tuesday
afternoon, especially given the potential of rather wet snow.
Farther south, confidence on ice amounts is low to medium. This
results in a conundrum of whether or not to issue an advisory for
lower-confidence icing that starts earlier than higher confidence
advisory-level snow that starts later to the north. Ultimately
decided to issue an advisory across the northern two tiers of
counties. While confidence is medium for icing across the Chicago
metro and west, a potentially colder solution of more snow than ice
would still warrant an advisory for moderate wet snow instead. In
other words, while precip type (snow vs. freezing rain) remains
unclear, there will likely be impacts either way. Farther south
along the I-80 corridor, there are some concerns that slightly
higher surface temps may significantly reduce icing amounts, so
have opted to not issue an advisory there at this time, but a
colder solution require an expansion to the south.

[wxman1952]

Winter Storm Watch for me now has been issued for late Monday through Wednesday. People with kids are already sick and tired of most or all of last week having no school..

[HillsdaleMIWeather]

18Z GFS is a touch north

[Chicago Storm]

Right now I’m thinking 1-6” snow/sleet spread across the area, lower towards I-80 and highest near IL/WI border.

Then probably an axis of 0.10-0.25” ice accrual across the heart of the LOT CWA as well.


.

[Baum]

11 minutes ago, HillsdaleMIWeather said:

18Z GFS is a touch north

looks snowier in these parts

[cyclone77]

Models still aren't giving much clarification for this area, as p-type and amounts still vary quite a bit.  Euro also very slow to get precip in here compared to other models, and also more meager on QPF.  First guess is a messy mixture throughout, with mixing p-types cutting down on anything too significant for a single p-type.  I'd much rather be sitting up in the nw DVN cwa where they have a good shot to receive mostly snow.  Should be a nice snow for CR crew.

[mississaugasnow]

1 hour ago, Ottawa Blizzard said:

Regardless, have to admit that this is one of the better snow seasons we've had this decade.

This storm has high bust potential for forecasters. The exact time of changeover, where the dry slot ends up and where exactly the low tracks will be big for the GTHA. 

My first call would be for a solid 6-10" event north of the 401 followed by freezing rain/ice pellets and then dry slotted. I dont think rain makes it that far north.

South of the 401 (Burlington-Toronto) I think 5-8" with freezing rain and ice pellets maybe a brief change over to rain before dry slotted 

Hamilton-Niagara 3-5" with several hours of ice pellets/freezing rain followed by a few hours of rain followed by dry slot. 

I think someone in Central/Eastern Ontario ends up with 20" 

 

 

[weatherbo]

[Cary67]

2 minutes ago, weatherbo said:

Not a good look for Chicago area. 

[Baum]

7 minutes ago, Cary67 said:

Not a good look for Chicago area. 

it's exactly what the forecast is. 1" south with Freezing rain to 6" up your way. Looks fine.

[mimillman]

16 minutes ago, weatherbo said:

This map has looked the same for every event the past 15 days 

[Malacka11]

1 minute ago, mimillman said:

This map has looked the same for every event the past 15 days 

Hopefully our luck changes with the next event. 

[Cary67]

2 minutes ago, mimillman said:

This map has looked the same for every event the past 15 

6 minutes ago, Baum said:

it's exactly what the forecast is. 1" south with Freezing rain to 6" up your way. Looks fine.

 Hope so but 18Z NAM looks to push more FZR up to the state line with a bit of a dry slot followed by a deformation axis just south of Chicago. Seems like were in a position of high bust potential at least snow wise

[Stebo]

Decent fluff event here tonight, looks like a solid 2-3" has fallen.

[RogueWaves]

Just now, Stebo said:

Decent fluff event here tonight, looks like a solid 2-3" has fallen.

You must've gotten the more dynamic weenie band. Just 0.7" of dense pixie stuff back here. At least it's white again..

[Harry Perry]

1 hour ago, mimillman said:

This map has looked the same for every event the past 15 days 

Was just going to say that haha.

[snowstormcanuck]

Looks like the jump north the 18z NAM took was an aberration.  Back SE so far on the 0z run, through 30.

[IllinoisWedges]

Both the 0z 12km NAM and 0z HRRR are pretty bigly on ice in the LOT area. 

[CoalCityWxMan]

18 minutes ago, IllinoisWedges said:

Both the 0z 12km NAM and 0z HRRR are pretty bigly on ice in the LOT area. 

2 ice storms in 7 days 

 

but I will say I think this one has the potential to be worse, with the last storm being a shorter duration/heavier precipitation event limiting accretion. 

[SchaumburgStormer]

1 minute ago, CoalCityWxMan said:

2 ice storms in 7 days 

 

but I will say I think this one has the potential to be worse, with the last storm being a shorter duration/heavier precipitation event limiting accrediting 

And even then, DKB got over .2” of accretion. 

[ILSNOW]

ouch

 

[ILSNOW]

COD map hope its wrong with ice amounts around and just west of downtown Chicago .

[Hoosier]

Likely would be a band of over .25" accretion if the NAMs are right.  

The bigger problem will come if there is an overlap area that gets significant ice and doesn't melt it before the winds kick in on Tuesday.

[Cary67]

0Z 3K NAM showing ice/sleet vs snow

[Hoosier]

May be of minor importance but the tree branches have a head start with building up snow/ice given the minor snow earlier and been getting freezing drizzle up until a short time ago when it flipped back to snow.

[Harry Perry]

37 minutes ago, Hoosier said:

Likely would be a band of over .25" accretion if the NAMs are right.  

The bigger problem will come if there is an overlap area that gets significant ice and doesn't melt it before the winds kick in on Tuesday.

Agreed. Temps aren’t looking like they’ll get AOA freezing for too long by much of the guidance - and a lot of the precip falling will be a lighter nature over a longer period of time. Between that and temps being in the mid to upper 20’s for you all the way this way, I’m growing increasingly concerned for the potential of some serious impacts from this system.