Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 230602 AAA

National Weather Service Jackson KY
202 AM EDT Sun Oct 23 2016

Issued at 202 AM EDT SUN OCT 23 2016

Made some minor adjustments to the lows based on the current
trends in observations. The coldest valleys are currently running
around 35 degrees. Will allow for a few more degree drop off;
however, some mid-level cloud cover looks to skirt by to our
northeast overnight, which should help to stifle the drop off.
Updates will be out shortly.

UPDATE Issued at 1050 PM EDT SAT OCT 22 2016

Hourly temperatures have been freshened up based on trends in
observations. High pressure will bring mostly clear skies and
light winds overnight. Lows in the valleys should reach the mid to
upper 30s range with patchy frost especially in the normally
colder locations. Frost wording has been adjusted in the HWO for
patchy frost in more of the valleys.

UPDATE Issued at 755 PM EDT SAT OCT 22 2016

Temperatures in some of the deeper eastern valley locations have
already dropped into the low to mid 40s with winds having
slackened or decoupled there. This combined with afternoon
crossover temperatures in the mid 30s have opted to lower min T
for some of the typically colder valley locations a couple of
degrees on average. Patchy frost will be possible in some of these


.SHORT TERM...(This evening through Sunday night)
Issued at 345 PM EDT SAT OCT 22 2016

19Z sfc analysis shows high pressure building into the area as low
pressure pulls away to the east. This is working to clear the sky
from west to east as the drier air advects in on northwest winds.
In general, the winds are running at 5 to 10 mph with a few gusts
to 15 mph, or so, thanks to good mixing. The return of sunshine
helped temperatures this afternoon climb into the mid 50s for
most locations while dewpoints mixed down to the low and mid 30s.
These lower dewpoints should make it tougher to get fog late
tonight but may hint at a potential for valley frost.

The models are in good agreement aloft through the short term
portion of the forecast as they all depict a large trough
gradually pivoting out of the Ohio Valley. The core of the initial
trough will depart tonight with heights rising locally, but
additional energy does dive into the Great Lakes, though on a
more shallow trajectory, Sunday night. Given the good model
agreement will favor a blended solution with a lean toward the
higher resolution HRRR and NAM12.

Sensible weather will feature a chilly night with mostly clear
skies and good radiational cooling. This should be enough for
some upper 30s in the valleys and a spot or two of mid 30s where
patchy frost is possible. Do not anticipate the frost being
extensive enough for an advisory tonight as it will be confined
to just the deepest, most sheltered valleys. Accordingly, will
highlight it in the HWO with a the potential for an SPS left to
the following shift. Saturday will be a very nice mid autumn day
with plenty of sunshine, breezy conditions, and temps in the mid
60s. A few wind gusts will approach 30 mph Sunday afternoon over
western parts of our area. Another cool night follows with mostly
clear skies and another ridge to valley temperature split, but
likely not quite cold enough for any frost.

Used the CONSShort and ShortBlend as a starting point for the
grids with some adjustments each night for lows - enhancing the
ridge to valley differences. PoPs are essentially zero - in line
with all guidance.

.LONG TERM...(Monday through Saturday)
Issued at 440 PM EDT SAT OCT 22 2016

The models are in fairly good agreement aloft through the bulk of
the extended. A flat ridge will spread through the South during
the first part of the week before another wave starts developing
over the Northern Plains moving east. It is this wave that leads
to a greater spread in the models as it moves into the Upper
Midwest with the GFS outpacing the ECMWF and both stronger than
the Canadian. The wave deepens into a strong trough Wednesday
into Thursday - deepening substantially as it moves into and
through the Great Lakes to end the work week. Its energy brushes
by the Ohio Valley with its trough axis passing through Kentucky
early Friday. Heights will then rise for next weekend, more so
from the GFS, and quicker, than the ECMWF. Given the broad
agreement through the majority of the period a blend looks to be a
reasonable starting point for the grids.

Sensible weather will feature a fairly nice stretch of weather
through mid to late week with dry conditions and moderating
temperatures. A dry front will shift east of the area Monday with
little change in air mass. The next cold front will move toward
and through the area on Thursday with a decent shot at showers
into Friday morning. Cannot rule out a stray thunderstorm with
this, but given the time of year will wait until it gets closer
to further evaluate the thunder threat. Dry weather follows into
the weekend, but there may be another front worthy of some PoPs by
Saturday afternoon per the GFS and that night in the ECMWF. For
now, will keep it dry Saturday while the models work this
difference out.

The main adjustments to the CR init was to hit the terrain effects
more each night and tighten up the PoPs late in the upcoming work


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)

VFR conditions can be expected through the period. Some mid-level
clouds will skirt by to our northeast through 12z. Light southwest
winds will pick up to around 10 kts, with gusts up to 20 kts this
afternoon. The winds will then weaken to between and 5 and 10 kts
by early this evening.




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