SnowTALK! Tuesday Edition

Risks today:

1) Tomorrow night (eastern counties)  1/2 Twix Bar
2) Late Thursday/Friday  2 Twix bars...for now.

ODDS AND ENDS
Low in Louisville this morning: 11°   *coldest since we dipped to 10° on 2/10/11

High so far today, 20°   If we fail to reach 22° it would have been our coldest afternoon since 1/8/10 when we only reached 19° for a high.

Coldest in our viewing area looks to be near Paoli, IN which dipped to 6°

What did you have at your house??

TOMORROW NIGHT:

A fast moving clipper will dive in a very sharp NW to SE fashion tomorrow night.

It will spread light snow across OH and east KY.  Snow ratios look high there----so 1-3" of snow could be possible in the heaviest bands.  As far as our viewing area...snow could fly east of I 65 with the I-75 region having the higher chance at accumulations.  Nevertheless, I would not rule out a light coating for eastern areas.  Watch for slick spots certainly if snow showers develop in your area.

LATE THURSDAY/FRIDAY
This one remains tricky.  We have been discussing this wave of energy on the blog for some time now.   As stated many times, you cannot just move cold Arctic air out of the way.  And yes, it is Arctic.  You define the term by source region ---not by how cold it is.  So while I think the talk that this cold is extreme is a bit much as it is not even close to record breaking---but IT IS significant that we haven't experience this in a couple of years.  So I guess it is all relative on how you want to use the term--but Arctic is correct when discussing it. 

Cold air is dense...and hard to push out of the way.  So our biggest ice/snow events in our area have came at a time when warm air has tried to bully its way in. 

The low expected to move in during this period---is going to attempt to do just that.

So let's break it down.

First---the NAM.

It has been trending colder with each run.  But still struggles with the warming aloft.

Latest sounding for early Friday shows we are below freezing (left of the 0°) at the surface.  I completely agree with that.  But notice the brief moment it goes to the RIGHT of the 0° mark as you go up into the atmosphere.  That is a solid freezing rain/significant icing sounding that shows up.

Here is the model:

While I would not rule that out COMPLETELY--- I think the profile trend is to cool the upper column down...and the EURO/GFS keep doing the same thing.

GFS in fact...keeps us LEFT of the 0° mark pretty much throughout the whole event.

BUT---notice the dry air aloft.  That keeps precip amounts down at the surface.  This sounding shows a very light snow event.

Here is the model:

The latest EURO just came in...and looks similar to the GFS in terms of a drier sounding....and cold in all layers... aka light snow.

So the 3 setups that the models are telling us:
1) significant icing..  up to 1/2" of ice...which would be a WARNING level event
2)  Column cools with decent moisture at place...3-6" of snow.  Which, again, would be a WARNING level event.
3)  The system is flatter on the charts...faster...  drier.  1" to maybe 2" of snow.  Which would be an ADVISORY level event.

Timing looks to be after midnight Thursday night-Midday Friday---at this time.

CURRENT THOUGHTS

Right now---there is more SUPPORT for #3 if you want to take the data at face value.  But I must stress that this system has not even developed---so determining moisture content is a huge challenge---even this close to the event time.  I personally would bet more on a colder upper atmosphere...so more snow than anything.  We definitely do not want option #2 as that would be a nightmare for the Friday morning rush. 

No need to call this a "winter storm" at this stage.  Just a system that needs to monitored carefully.  We need to trend the temps tonight/tomorrow to see how well they are verifying with the pattern in place.  That will help us.

These complex systems are not new.  They have been a thorn in our side after Arctic airmasses like this for many many many years.  We just now have more data than ever to examine the setups.  Sometimes---that can be a bad thing.  Too many voices yelling in one room.  That is why we have to look at the pattern..and history.  And history has cold us that Kentuckiana usually has a significant winter event when you try to warm up from Arctic cold. 

We shall see.

Stay tuned.  Many updates on this.

I wanted to touch base on what will happen Sunday night---but I will wait on that until tomorow.  One thing at a time.

Comments

[Marcus]

I see bust in our future lol