Halloween Forecast for Central Kentucky

UPDATE 30-October-2014:

We've been tracking a storm system for over a week now that threatens to bring the first blast of winter to central Kentucky this weekend.  It appears that things are coming together just as predicted.  A major blast of cold air is coming and temperatures will fall to the 20s by Sunday morning.  Ahead of this, rain will change to snow by Saturday morning and could possibly dust a few cars and trees and Halloween decorations before it's done, especially along and east of I-75.  This will be my final update on this storm.  Get ready because it's about to get COLD!!  I'll leave you with the latest forecast discussion from the fine folks at NWS Louisville:

Latest GFS, NAM, and ECMWF are in pretty good agreement showing an
deep upper low diving SSE across the eastern OH Valley Friday night.
The GFE 18z ensembles showed the trough aloft being 3 to 4 standard
deviations below normal which is significant. With this system will
come cold air advection and dynamic cooling aloft. The model-
indicated pattern suggests possible development of a winter-like
deformation band within a tight isotach (lines of constant wind
speed) gradient in the left exit region of a 300 mb jet streak
diving south over the lower OH Valley. In these types of patterns, a
definitive mesoscale band of wintry precipitation normally occurs
assuming temperatures within the moist layer and at the surface are
sufficiently cold. In this system, the models suggest all this to
occur, which would suggest a band of snow over the eastern half of
the forecast area, especially east central KY late Friday night.
Model soundings show moisture extending up to between 500 and 600
mb, and cold enough in the moist layer for ice crystal formation
which would stay as mostly snow as it fell to the ground.

If this verifies, then scattered rain showers during the day Friday
likely would diminish or end in the evening, with a band of some
snow developing late at night which would move quickly southeast and
end by Saturday morning with up to an inch or so of snow possible
mainly across the Bluegrass, and especially on grassy areas.

UPDATE 27-October-2014:

The Euro model has sort of taken on the look of the GFS that I posted last week (below).  Imagine that.  Low pressure near the Great Lakes may drive a sort of "back door" cold front through here Friday night and into Saturday morning with much colder air arriving.  Both models take us below freezing Halloween night and into the first morning of November.  The question is, will any precipitation accompany this front?  It's still a little early to tell, but there remains a small chance that we could see a few snowflakes early this coming weekend, especially in eastern Kentucky.  

Here are the temps and precip predicted by the European model.  Notice the freezing line dropping into Kentucky by 8:00PM Halloween and then the precip shield which is depicted as getting really close to the Bluegrass that night.  Interesting...  just something to watch.

As we wait to see how El Nino is going to shape up for winter and what impact it may have on our temperatures and snowfall, we are currently soaking up the final nice days of the year in Kentucky.  Sunshine has returned after a week or two of ICKY weather and by the weekend we’ll see the 70s for highs come back for several days…well into next week.  Ahhh…  enjoy it!!  The leaves are peaking at this time as well, which will make for some absolutely delightful days to finish out October.

Speaking of finishing out October…the last day of the month, Halloween, falls on a Friday this year and that means big plans for trick-or-treat and parties/social events/etc.  What’s the weather going to look like?  Will it look great like a piece of hot pumpkin pie with whipped topping or will it look scary like a headless horseman carrying a bloody sword?

The models are hinting at a cold front that would sweep through mid to late week and that would usher in much colder air for the weekend.  At the same time that is going on, a Nor’easter will move up the east coast.  This *may* throw enough moisture back into parts of KY to interact with the cold air advection sweeping in behind the front and allow a few snowflakes Halloween night.  The weather for that weekend does indeed look active and there will be a LOT of eyes on this forecast in coming days.  We are over a week out and there is lots of uncertainty right now.  I will update later today with the new 12Z data and show you the current thinking on the situation.

Now go outside and enjoy this nice weather!

UPDATE: Here's today's 12Z GFS run.  You can see the low wrapped up in the northeast with strong cold air advection bringing the CHILL into Kentucky Halloween night.  It's conceivable that we *could* possibly see a few flakes.  As always, I'll fine tune this forecast in a few days.

Shawn