Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 231752

National Weather Service Jackson KY
1252 PM EST Thu Nov 23 2017

Issued at 1250 PM EST THU NOV 23 2017

Have made some minor updates throughout the morning to make sure
the near term forecast for temps, dew points, and winds was on
track with the current observations. Otherwise, no major changes
needed with high pressure and mostly sunny skies in control
across the region. A few passing high clouds are in place across
the far northern CWA but are scattered at most and posing little
concern. All updates have been published and sent to NDFD/web.

UPDATE Issued at 625 AM EST THU NOV 23 2017

A cold, but quiet Thanksgiving morning out there. Temperatures
have settled into the upper teens to lower 20s across most of the
area. Outside of some very minor tweaks to the latest hourly
trends, no updates needed this morning.


.SHORT TERM...(Today through Friday)
Issued at 307 AM EST THU NOV 23 2017

High pressure will dominate the weather through Friday. At the
same time airmass will start to moderate over the region, allowing
for slightly warmer afternoon highs today and even warmer readings
on Friday. Overnight lows tonight will remain on the cold side
with light winds and clear skies allowing for good radiational
cooling. This will put lows in the valleys fairly close to the
readings we are seeing this morning. Ridges and more unsheltered
areas may see a slight increase in low temperatures tonight, but
still likely below freezing.

.LONG TERM...(Friday night through Wednesday)
Issued at 400 AM EST THU NOV 23 2017

While the models all begin the extended portion of the forecast in
good agreement aloft, they diverge early in the new work week
lowing confidence in any specific solution with time. The models
depict a gradual amplification of a trough centered over the Great
Lakes heading into the weekend. With this, a trough axis and
energy band will push across Kentucky by Saturday evening with
similar timing and strength. Heights will rebound mildly in the
wake of this trough heading into the new week, though additional
batches of weak energy will pass overhead Sunday and Monday. At
this point, the models` spread increases with the GFS and ECMWF
differing on a large trough moving on shore of the West Coast -
the GFS being quicker and shallower. Downstream, this keeps the
pattern out of sync over Kentucky through mid week with respect to
the amount of any ridging that forms over the state. With time,
the West Coast trough moves into the middle portion of the nation
though the GFS is much faster than the ECMWF as this key feature
approaches Tuesday night. The GFS`s version of this trough passes
through Kentucky early Wednesday while the ECMWF keeps its back
to the west through Thursday. With the differences later in the
period anticipated the need to make some adjustments for the
Wednesday time frame to account for a blend of these nearly
diametrically opposed solutions.

Sensible weather will feature a continuation of our period of
quiet and seasonable conditions as one slow moving area of high
pressure is replaced by another with little moisture available for
the fronts in between. The first of these boundaries looks to move
through early Saturday with just a very small potential for a
shower - but left out of the forecast for now. Following this,
high pressure keeps a lid on all activity well into the new work
week. The question arises from Tuesday night into Wednesday when
the GFS pushes a cold front into the state with a potential for
showers while the ECMWF keeps high pressure in control. Not
prepared to bite on any particular solution at this point have
allowed for increased PoPs to close out the extended forecast and
not clear the area too quickly, though still faster than the
blends. Temperatures will be seasonable through the period with a
slow moderating trend noted - at least through Tuesday.

Made just minor adjustments to the temperature grids each night
anticipating a small to moderate ridge to valley split. Also,
narrowed the range of slight chance to chance PoPs with the cold
front for later in the new week - per collaboration with neighbors
and with consideration of the WPC guidance.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)

VFR conditions (including mostly clear skies) and light winds
will prevail through the period as high pressure remains in place
across the region.




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