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Mid-week potential of something somewhere


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27 minutes ago, A-L-E-K said:

that was good content

we put together another real winner of a season, maybe one of these years we luck our way into another big bog before the dallas climo kicks in

Scars run deep for model trust. Hard not to Jerry Taft every forecast. 

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Nice AFD from Ryan at KIND (and one of the longest short term's I've ever seen)...

.SHORT TERM /Tonight through Thursday Night/...
Issued at 330 AM EST Tue Feb 25 2020

Forecast challenges quite a bit greater than 24 hours ago as the
model suite has shifted the potential for accumulating snow further
to the southeast than previous runs had it. The overall model mayhem
has led to some drastic changes to the forecast from just a day or
two ago...highlighted by an increasing threat for accumulating
snow...especially over the northern half of the forecast area. Still
though with such a rapid change within many of the model
solutions...confidence is nowhere near where would like to see it at
this stage. A headache inducer to say the least.

So why such large scale changes over just the last few model runs
from just a few tenths of snow to potentially needing to consider
headlines?  Much has to do with the model suite`s handling of the
evolution of the upper level pattern as the energy diving out of the
northern Rockies carves out a deep trough over the center of the
country by Wednesday. Previous runs had a cleaner transition of the
energy aloft from the weakening wave over the region this morning
into the expanding energy aloft dropping in from the northwest.
Model guidance this morning still has this transition taking place
but it is quite a bit messier with strung out energy aloft described
in the near term section above aiding in less phasing at the surface
and subsequently a shift south to almost all of the key features
involved with this storm. A developing upper low will close off over
Oklahoma/Kansas this evening then deepen as the energy aloft carves
out the trough as it tracks across the Mississippi and Ohio Valleys
Wednesday.

Just two days ago...a new surface wave was developing over northern
Illinois late tonight and early Wednesday in tandem with the upper
low but now due to the strung out nature of the waves aloft ahead of
the approaching northern stream energy...this secondary low never
develops with the current surface wave over the region drifting
slowly east near the Ohio River. This results in the colder airmass
pivoting into the region much faster than originally thought...
perhaps as early as this evening in the northern Wabash Valley
before expanding southeast across the area into Wednesday. Model
soundings support a gradual transition to snow from rain overnight
into Wednesday morning over the northwest half of the forecast
area...with a rain to snow/rain mix over the southeast half on
Wednesday. Low level thermals support snow as the primary precip
type over the entire forecast area by late day Wednesday.

So while there is an increased threat for snow accumulations late
Tuesday night into Wednesday...especially along and north of the I-
70 corridor...several caveats remain that must be considered in
determining amounts. The model suite is capturing a trailing surface
trough behind the departing low pressure system with a trowal
extending west in tandem Wednesday morning. The strong energy aloft
mentioned above will dive around the base of the approaching upper
low and into the region Wednesday morning enhancing diffluence
aloft. These features combined with the potential for a mid level
deformation axis to rotate across the northern half of the forecast
area could support a threat for heavier bursts of snow through the
day. With that being said...surface and ground temps will be a
factor for a good chunk of the day with low to mid 30s common across
the region before turning colder by Wednesday evening. The above
factors could lead to heavier snowfall rates that would overcome
these marginal temps but some melting of snow does seem likely when
rates remain lighter which will knock totals down.

A lot to consider here and a lot that could bust potential snowfall
totals. That being said...feel strongly from a public impact
standpoint that a headline needs to be introduced over northern
counties where confidence is highest at the moment for impacts and
accumulations. Will introduce a Winter Storm Watch...essentially
north of a Crawfordsville-Anderson line...which offers the most
flexibility at this point considering the constant model shuffling
that has occurred over the last 24-48 hours and may continue with
the 12Z runs today. Have 3-5 inches in these areas...1 to
potentially as high as 3 to 4 near the I-70 corridor in the
transition zone and lighter amounts further south.

Fully expect that an Advisory at a minimum will be needed over parts
of the northern forecast area should trends continue and the
dayshift will have an additional set of runs to determine if further
adjustments in location and amounts is needed. The main message at
this point is that adverse winter weather and snow accumulations are
becoming more likely for late Tuesday night and especially Wednesday
over the northern half of the forecast area.

Snow will gradually diminish Wednesday night as the upper low shifts
east of the region. High pressure will build in on Thursday but
cloud coverage will remain higher as a fast moving clipper system
dives through the Missouri Valley. This feature will track into the
lower Ohio Valley Thursday night. While the focus of the
precipitation will be southwest of the forecast area...flurries or
light snow may skim the lower Wabash Valley early Friday. Plan on
keeping the forecast dry at this point but will be something to
monitor going forward.

Temps...heavily utilized ConsAll numbers for hourly temps late
tonight in Wednesday to try and better capture the expansion of the
colder air. Temps will drop steadily after 06Z tonight back into the
lower and middle 30s with little to no recovery on Wednesday before
the much colder air arrives Wednesday night. Generally undercut MOS
guidance as a result for highs Wednesday. Much colder Thursday with
some portions of the area remaining in the 20s. Lows will fall back
into the teens over much of the area by Thursday night.

&&
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On 2/23/2020 at 8:53 AM, Chicago Storm said:

For reference for ORD...

 

The last 10”+ snowstorm was Nov 20-21st 2015. (11.2”)

 

The last 12”+ snowstorm was GHD2 in 2015, and the previous before that was GHD1 in 2011.

 

 

.

 

Insane the last time Chicago saw a 10” storm was 4.5 years ago, and likely will end up being 5+ years. This has been a horrendous stretch.

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Rates have actually allowed a coating to start on most surfaces. Temp has dropped 3 degrees as well, sitting at 33. Guessing wet bulbing is the cause.

 

Either way wasn't expecting to see snow until late morning early afternoon, still have a forecast high if 38, which it was 38 at midnight so they wouldn't be wrong.

 

They have 38 at 2pm in the grids, but supposed to be 4 degrees warmer currently and holding steady.

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44 minutes ago, snowcaine said:

6" seems like a reasonable call for Toronto at this point, I'll take it.

Slightly OT but it always used to weird me out when Toronto posters would talk about getting rainers. I always thought of Canada as this place way far to the north that's inevitably colder and snowier than us. I have to remember Toronto is only a few degrees of latitude north of me.

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28 minutes ago, CheeselandSkies said:

Slightly OT but it always used to weird me out when Toronto posters would talk about getting rainers. I always thought of Canada as this place way far to the north that's inevitably colder and snowier than us. I have to remember Toronto is only a few degrees of latitude north of me.

haha your not alone. At least you live in Wisconsin so not a lot of interaction with Canada. Meeting people at Bills game and they ask how we handle the cold and snow and that they could never live in Canada because of that. The GTA is only 45 minutes across the border and Buffalo is right on the border so its not like theres a game of thrones type wall and were wildlings (way off topic now haha) 

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1 hour ago, CheeselandSkies said:

Slightly OT but it always used to weird me out when Toronto posters would talk about getting rainers. I always thought of Canada as this place way far to the north that's inevitably colder and snowier than us. I have to remember Toronto is only a few degrees of latitude north of me.

Actually, almost exactly the same latitude as Madison. We jut out on a peninsula in the SE part of the country. We're Canada's Miami.

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1 hour ago, CheeselandSkies said:

Slightly OT but it always used to weird me out when Toronto posters would talk about getting rainers. I always thought of Canada as this place way far to the north that's inevitably colder and snowier than us. I have to remember Toronto is only a few degrees of latitude north of me.

That Jan 10-12 storm was a quality rainer. 3” in mid Jan. Can’t get much better than that. 

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2 minutes ago, snowstormcanuck said:

12z 3km NAM has a foot at YYZ, 8 or 9 inches from the synoptic and then the rest from a gnarly lk huron band afterwards with impressive inland penetration.

Sounds like fun.

Sounds like a Dec ‘16 repeat band. RGEM is a bit more east with the heavier amounts. Closer to 8”.
 

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