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Area forecast discussion 
National Weather Service Jackson Kentucky
633 am EST sun Dec 21 2014

issued at 632 am EST sun Dec 21 2014

Made a few tweaks to the sky cover grids for early this morning. A
swath of low level stratus clouds have stubbornly persisted across
northern portions of the forecast area overnight. These clouds look
like they will persist for several more hours based on current
satellite trends and the latest models soundings. Therefore...the sky
cover grids from 9 to 12z have been updated to reflect the cloudiness
up north. The rest of the forecast was in good shape with no further
changes necessary.


Short term...(today through monday)
issued at 310 am EST sun Dec 21 2014

A fairly calm period is on tap for the first 36 hours of the
forecast. Lingering cloud cover will continue to move out of eastern
Kentucky early this morning north of the mountain Parkway. After a
few hours of mostly clear skies...a few low and high level clouds
will begin to slowly move back into the area from the southwest ahead
of an area of low pressure that will move past well to our south.
This low pressure area is prognosticated to move across the eastern
Tennessee Valley tonight and tomorrow. As it does so...a bit of
moisture that the system brings from the Gulf of Mexico could spill
over our eastern mountains. This meager moisture may even spawn some
isolated rain showers in our far eastern counties along the Virginia
border. Southeasterly flow associated with the passing low will make
even isolated showers a bit of a stretch...but there could be just
enough moisture available for a few to a slight chance of
rain will be carried in our southeastern counties from late Sunday
into through middle morning morning. Broken to overcast low level cloud
cover will likely be the primary weather feature associated with the
area of low pressure as it moves across the Tennessee Valley and
southeastern Continental U.S..

Temperatures will start out right around normal...with highs today
expected to climb into the middle to upper 40s across the area.
Locations north of the mountain Parkway may only reach the lower 40s.
With cloud cover on the increase...and winds shifting to the south
and southeast...overnight lows should not be quite as cold as this
mornings forecast lows. We should see min temperatures on Saturday morning
generally in the low to middle 30s across the area. Once persistent
southeasterly winds become established on Sunday...downslope warming
will occur...allowing temperatures to warm significantly around
eastern Kentucky. Highs on Monday should have no problem maxing out
in the low to middle 50s.

Long term...(monday night through saturday)
issued at 310 am EST sun Dec 21 2014

Unsettled weather is expected heading into Christmas morning...but
we should dry out for the majority of the Holiday weekend. The
exception will be a shearing out cold front that could bring a small
chance of rain to the area late Friday or Saturday.

To begin the period...a northern stream trough will reside across
the Central Plains with southeast flow locked in across eastern
Kentucky. This downsloping flow will keep dry weather across eastern
Kentucky through Monday night and likely much of Tuesday. Further
away from the effects of this downsloping...we may see some rain
push into the Bluegrass or south central Kentucky by midday Tuesday
or sometime in the afternoon. While models continue to differ on how
this whole system thing seems pretty sure is that we
will have tremendous lift and forcing go across the area Tuesday
night through Wednesday as a cold front works across the area. For
this reason...will go with categorical probability of precipitation. The GFS remains more
pronounced with the middle level trough heading into Wednesday and
Wednesday night...while the European model (ecmwf) holding to a less wrapped up
system. These two widely different scenarios brings into question
exactly when we might see any transition over to snow across the
area. In fact...the GFS never really gets cold enough air into the
area to support much snow at all. What cold air it does portray does
not coincide with an area of lift or very deep moisture. While the
European model (ecmwf) looks a little better for snow...even it has been backing off
on the snow potential. This combined with an unfavorable upslope
westerly wind...will really make it hard to see much in the way of
snow shower activity. While we may still see a few flakes...thinking
this may not be much of an impact for our area Wednesday night.

The one concern that still exist is the high wind potential on
Wednesday as a cold front surges east across the area. Winds along
and just behind the front could gust as high as 45 miles per hour. While we
should see winds subside some into Wednesday night...some wind gusts
to 35 miles per hour will remain possible.

By Christmas day ridging will already be pushing into the area with
highs making a nice recovery to around 50. Our next weather maker a
moisture starved cold front will head towards the area late in the
week. Models differ quite a bit on have backed off on
the higher probability of precipitation and gone with a longer period of low chance probability of precipitation
from Friday into Saturday. Most likely any rain chances will be
limited to a 3 to 5 hour window...but pinning it down this far out
is just about impossible. Mild weather will persist into Saturday
before colder air returns for the rest of the weekend in the wake of
the cold front.


Aviation...(for the 12z tafs through 12z Monday morning)
issued at 632 am EST sun Dec 21 2014

A few things of note at the taf sites this morning. Sme has been
experiencing some light fog over the past several hours...and will
likely see this fog persist through about 13z. After that the fog
should burn off. Sjs...loz...and jkl are all experiencing clear skies
with VFR conditions. The one exception this morning is sym. A swath
of low level stratus clouds has kept sym blanketed with MVFR ceilings of
around 1.5k over the past several hours. This trend in cloudiness is
expected to persist through 16 or 17z before the clouds finally begin
to scatter out. All of the taf sites should begin to see a few low
and high level clouds moving back in around 21z today as an area of
low pressure moves by to our south and southeast.


Jkl watches/warnings/advisories...


short term...Arkansas
long term...kas

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