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Area forecast discussion 
National Weather Service Jackson Kentucky
750 am EST Sat Feb 28 2015

Update...
issued at 750 am EST Sat Feb 28 2015

Middle level and upper level cloud cover streaming in overnight has
kept up low temperatures across the area. No location dropped into
the single digits overnight. Besides temperatures...the forecast remains
on track. Some of this cloud cover is showing up on the regional
mosaic but a few flurries may still be possible heading in through
midday. Otherwise...the main concern through the short term will
be the continued possibility of freezing rain tonight and the 06z
NAM soundings seem to continue to highlight this. The warm nose
continues to be such that...its difficult to see snow south of the
Ohio at this point. Still the amount of dry air to overcome
coupled with the uncertainty of the amount of moisture being
advected in to overcome the dry layer before surface temperatures warm
above freezing towards dawn continues to be puzzling. Then the
amount of evaporative cooling coupled with any snow cover...the
freezing rain and even sleet in transition remain a credible
threat. Will pass on the Special Weather Statement and inform the dayshift.

&&

Short term...(today through sunday)
issued at 327 am EST Sat Feb 28 2015

Current conditions across eastern Kentucky feature northeast low
level flow with middle and upper level cloud cover streaming in from
the southwest. Despite the cloud cover moving in
overnight...temperatures will still be in the teens for lows
tonight...especially in the valleys that are still supporting a
decent snowpack. Within this weak disturbance will be some
isolated flurries moving through the area into the after dawn
hours.

Heading into the day...850 southwest flow sets up over the Ohio
River valley with a 30 knot ll jet. Overrunning precipitation will then
develop by Saturday evening into northern portions of central
Kentucky and into Indiana as well as Ohio. This will bring precipitation
into eastern Kentucky by or shortly after 06z tonight. With this
set up...there are a few concerns. Currently the area is under a
pretty dry air mass there will likely be instances across the area
where precipitation will wet bulb cold enough for freezing rain in most
areas...especially where there is decent snowpack. If the amount
of quantitative precipitation forecast expected is not robust at onset...the column wont saturate
in time before surface temperatures warm enough for all rain to fall. Hi
res model blends hint at this as well with dew points rising into
the upper 20s in most locations by 06z. Current thinking based
upon what the NAM and sref are advertising...the ll jet looks to
be strong enough to bring moisture northward and saturate the
lower levels. Enough evaporative cooling will take place Saturday
night for a few hundredths of freezing rain. Sleet may mix in at
times but this will be a mainly transient precipitation type for this
event. Will continue to highlight this in the severe weather potential statement but may be
needing at least a Special Weather Statement at this point for the threat...especially
noticing models are a bit more aggressive bringing precipitation into
the area.

Lower levels should warm enough by middle morning Sunday for precipitation
type to be all rain across the area as some warm surface
temperatures not seen in quite awhile advect into the area on
Sunday afternoon. Highs for Sunday will warm into the upper 40s to
near 50 which is actually normal for this time of year.

Long term...(sunday night through friday)
issued at 400 am EST Sat Feb 28 2015

Very active and messy weather on tap in the extended. The GFS and
European model (ecmwf) models were not in the best of agreement regarding precipitation
onset and evolution during the period...with the European model (ecmwf) being
slower and not quite as wet as the GFS to begin the period. The
initial precipitation event looks to be in full swing Sunday night
and Monday...as a cold front pushes across the area. Most of the
precipitation with this first boundary should be in the form of rain.
Some snow is expected to develop in the moist upslope flow behind
the departed front on Monday. Any accumulations with this snow
should be minimal at best. A ridge of high pressure is then
expected to settle over the area for a short period of time Monday
afternoon and evening. Then...a second more dynamic weather system
is prognosticated to take shape over the Southern Plains. This system is
expected to move northward...pushing its warm front across the
Tennessee and Ohio Valley regions Monday night through Monday
morning. Moist air overrunning the front may allow for a messy
mix of rain...freezing rain...and perhaps some snow during this
period. Light ice accumulations will be possible...especially
north of the mountain Parkway...where a couple of hundredths of an
inch of ice may accumulate on exposed and elevated surfaces. The
air at the surface should be warm enough my midmorning on Tuesday
for the precipitation to fall as all rain. Once the warm front has past
US by...a strong cold front is then on tap to push across the area
from the northwest. This boundary will linger across the area for
a couple of days. Widespread rain showers...capable of producing
moderate to locally heavy rain at times...will overspread the area
Tuesday through Wednesday. This rain in and of itself may lead to
flooding issues. Combine this rain with runoff from melting
snow...and things may get interesting. The primary concern with
this event will be warming temperatures and the melting of the
snow pack that is currently in place in the headwaters of the
Kentucky...Cumberland...and Big Sandy rivers. With the models
still producing a good deal of precipitation to begin the week...we will
continue to highlight the potential for flooding next week.

The precipitation is expected to linger through the end of the day
on Thursday before finally moving of to our east. The rain will
change to snow Thursday evening...as cold air begins filtering
into the region behind the cold front. As winds shift to the
north...and upslope flow begins to occur...the snow will become
more widespread. Light accumulations will be possible as snow
moves overspreads the entire area by late Wednesday night. The
snow will taper off Thursday morning as the front moves further
east...and the fronts parent trough aloft takes its energy east as
well. Light rain and snow showers will linger through Thursday
afternoon before finally coming to and end just before 0z Friday.

Temperatures throughout the period will fluctuate quite a bit.
Temperatures Sunday night and Monday look to be a bit below normal...with
lows in the 30s and highs in the 40s. After another cold night
Monday night...with lows ranging from the middle 20s in our north and
the lower 30s in our south...the Mercury is expected to surge into
the middle to upper 50s by Tuesday afternoon. Wednesday looks to
almost as warm with most of the area likely to see highs in the
low to middle 50s. After the cold front moves through the area
Wednesday night...another surge of very cold air is forecast to
settle over the area. Thursday mornings lows are expected to drop
into the low to middle 20s across most of the area...with a few
locations north of i64 perhaps falling into the upper teens. This
air mass will make its primary push into the area Thursday and
Thursday night...with highs on Thursday topping out mostly in the
low to middle 30s. Friday mornings lows will mark the coldest
temperatures of the upcoming week...with minimum values ranging
between 10 and 15 degrees across the area. Temperatures will only
be slightly warmer Friday and Friday night as winds gradually
shift to west and then southwest. We will see only a slight
improvement in temperatures to end the week...with forecast highs
on Friday in the middle to upper 30s for most locations...and
overnight lows around 20.

&&

Aviation...(for the 12z tafs through 12z Sunday morning)
issued at 640 am EST Sat Feb 28 2015

VFR conditions will continue through much of the taf forecast
period. Middle level cloud cover will continue to move through the
area today. Light and mainly variable winds are expected. Some
MVFR ceilings will make it into the area by 00z tonight as rain will
develop into the area by 06z with sym and points north seeing
some freezing rain. Expect most sites to see field mins after
06z.



&&

Jkl watches/warnings/advisories...
none.
&&

$$

Update...shallenberger
short term...shallenberger
long term...Arkansas
aviation...shallenberger

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