Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 231530 AAA

National Weather Service Jackson KY
1130 AM EDT Sun Oct 23 2016

Issued at 1130 AM EDT SUN OCT 23 2016

15Z sfc analysis shows high pressure sliding just to south of the
area. This provided, and continues to provide, clear skies through
the night and into Sunday. It was the clear skies and light winds
that helped to maximize the cooling early this morning and
resulted in areas of frost in the valleys and many reports of lows
in the mid 30s. Now temperatures have climbed into the mid to
upper 50s for most places, though some colder spots are only
slowly coming up through the 40s. Meanwhile, dewpoints are
running in the upper 30s and lower 40s. Winds are relatively light
so far this morning, generally from the southwest at 5 to 10 mph.
These will pick up by early afternoon as higher winds mix down
from aloft and the pressure gradient is realized. Temperatures are
on track for a pleasant day, likely topping out in the upper 60s
to lower 70s. Have updated the grids with the latest ShortBlend
data along with the current obs/trends. These have been sent to
the NDFD and web servers along with an updated set of zones and
new HWO - mainly to remove morning/frost wording.

UPDATE Issued at 815 AM EDT SUN OCT 23 2016

Freshened up the hourly temperatures...dew points...and sky cover
according to the latest satellite and observational trends. The
diurnal rise was slowed, given the chilly start in the valleys.


.SHORT TERM...(Today through Monday)
Issued at 355 AM EDT SUN OCT 23 2016

The latest surface map features high pressure centered across the
Gulf Coast states, with a surface ridge aligned northeast into
eastern Kentucky. Broad low pressure is moving east across the
northern Plains. Aloft, a deep upper level low is pulling north
across northern New England, with a short wave trough skirting the
U.S./Canadian border close to Minnesota. Broad ridging is
controlling across the lower and middle Mississippi Valley.

Temperatures are chilly in the valleys of eastern Kentucky this
morning, with a few spots reporting as cool as 33 degrees, with
some patchy frost/fog likely. The surface ridge will scoot off to
the southeast today, as low pressure quickly moves into Great
Lakes/Ohio Valley. A cold front will approach from the northwest
tonight, before moving through our area by Monday morning. High
pressure will then build in from the northwest.

Today will feature a good rebound in temperatures, thanks to
plenty of sunshine, and breezier southwest winds. Highs will be in
the upper 60s to lower 70s. Tonight will be milder with the
approach of the cold front; however, still expect some of the
eastern valleys to reach the lower 40s, while ridges stay about 10
degrees warmer.

Winds will shift to the northwest on Monday, helping to knock back
highs a few degrees, despite another mostly sunny day.

.LONG TERM...(Monday night through Saturday)
Issued at 355 AM EDT SUN OCT 23 2016

Models continue to be in reasonable agreement this week, but are
trending towards a weaker shortwave trough for late Wednesday and
Thursday, meaning lower rain chances and less rainfall.  The period
will start off Monday night with high pressure building in from the
north. This will yield clear skies and cool temperatures for Monday
night. Some of the eastern valleys will likely dip into the mid 30s.
Conditions should favor more fog formation as cross over
temperatures will be somewhat high (around 40 at best) going into
the overnight hours. Thus, frost not a significant concern for
Monday night. However, heading into Tuesday, we will mix into some
very dry air just off the surface with dewpoints likely crashing to
around 30 in places during the afternoon.  This will also send highs
higher into the mid to upper 60s (generally above guidance). While
the ridging will slide eastward by Tuesday night, gradient will
remain somewhat weak allowing valleys to decouple and setting up our
best shot at frost this week. For now will include some fog near the
river valleys, with frost elsewhere, and only in the valleys as
ridgetops should stay a bit milder in the lower 40s.

By Wednesday, a warm front will shift northward with south to
southwest winds developing. This will bring in milder temperatures
along with slightly higher dewpoints.  By Wednesday night, we could
see some showers develop along the warm front as it stalls over
northern Kentucky.  The better chance of rain will come Thursday as
the shortwave trough pushes across the Ohio river valley.  As
mentioned above, overall forcing and moisture is much more in
question today, leading to a weaker system and lower rain chances.
GFS and ECMWF are in fairly good agreement, so the lower rain
chances seem reasonable.  System and forcing will depart quickly
Thursday evening, but a secondary dry cold front will slip south
overnight, bringing in cooler weather to round out the week.  Mid
level ridging will return by Saturday with temperatures quickly on
the rebound as we head into next weekend. Models do start to diverge
through the weekend with the GFS laying out a boundary across
northern Kentucky, while the ECMWF brings in a rather significant
shortwave ridge ahead of another system for Sunday.  For now, opted
to keep the forecast dry and wait for models to work things out
before introducing rain chances into the weekend.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)

VFR conditions can be expected through the period. Wind will be
the main concern today, as a cold front approaches from the
northwest. Light southwest winds will pick up to around 10 kts,
with gusts up to 20 kts this afternoon. The wind will then
diminish to between and 5 and 10 kts by early this evening.




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