Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 180520

National Weather Service Jackson KY
120 AM EDT Mon Sep 18 2017

Issued at 120 AM EDT MON SEP 18 2017

GOES-16 Advance Nighttime Microphysics RGB showing fog becoming
solidly entrenched in the valleys once again tonight. Given the
past few nights, have opted to go ahead with an SPS to cover the
dense fog through 10 am Monday morning. Conditions are very
similar to last night, but perhaps visibilities and temperatures
in the obs about an hour behind the pace set last night. Thus,
overall, very little distinguishable difference between the two

UPDATE Issued at 1123 PM EDT SUN SEP 17 2017

Forecast still on a good track late this evening. Loaded in the
latest observations to make sure the near term forecast was on
track with current conditions. All changes have been published
and sent to NDFD/web. A new forecast package will be sent out to
change to overnight wording.

UPDATE Issued at 934 PM EDT SUN SEP 17 2017

Forecast seems to be in good shape so far this evening. Freshened
up the near term grids to make sure they were on track with
current conditions. All changes have been published and sent to

UPDATE Issued at 635 PM EDT SUN SEP 17 2017

Did a quick update to freshen up the near term grids, making sure
the temps, dew points, winds, and clouds were on track with
current conditions. This resulted in only minor tweaks, including
warming temperatures across our SW for the next couple of hours.
All changes have been published and sent to NDFD/web. No updates
to the forecast package are needed at this time.


.SHORT TERM...(This evening through Monday night)
Issued at 450 PM EDT SUN SEP 17 2017

20z sfc analysis shows relative high pressure through the area
and this is keeping the shower threat at bay while some activity
is noted well to the west. On satellite, a cu field at near 5k
feet is starting to diminish as the sun is heading down.
Temperatures did get up to the low 80s most places, just above
normals and the earlier guidance. Meanwhile, with light northerly
winds, dewpoints are generally in the lower 60s.

The models are in good agreement aloft through the short term
portion of the forecast. They all depict a weakening ridge over
the southeast part of the nation. Through this, some weak mid
level energy will pass over Kentucky. The first patch of these
fade out tonight with another one reaching the northern part of
the area Monday afternoon before dissipating to the north into the
night. Given the model symmetry will favor a blended solution
with a lean toward the higher resolution CAMs and a good bit of
persistence - especially at night.

Sensible weather will feature more of the same in this relatively
stagnant pattern. Expect mostly clear skies at night with areas of
fog developing toward midnight and becoming locally dense in the
river valleys. Monday will be another warm late summer day with
partly sunny skies and just a small chance for an afternoon shower
or thunderstorm and mainly just over our Bluegrass region in the
northwest parts of the CWA.

Again used the CONSShort and ShortBlend as the starting point of
all the grids making some adjustments to the temperature ones
each night based on terrain in anticipation of small to moderate
ridge and valley splits. As for PoPs, kept them in for Monday
afternoon as the sfc high and ridge aloft is not that strong and
there have been hints of convection in the models for that time
frame in the past couple of runs.

.LONG TERM...(Tuesday through Sunday)
Issued at 300 PM EDT SUN SEP 17 2017

The latest blended model data suggests that eastern Kentucky will
see periods of showers and thunderstorms from Wednesday through
Saturday. Any storms would occur mainly during the afternoon and
early evening hours. There will be a couple of days when most or
all of the rain will occur along and south of the Mountain
Parkway, and a few other days when the showers and storms will be
scattered across the entire area. It still appears that
temperatures in the extended will be well above normal, with daily
highs in the low to mid 80s expected, and nightly lows ranging
from the upper 50s to mid 60s across the area. Winds should be
generally light and variable.


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

Another night of dense valley fog will be seen in eastern
Kentucky with the fog lifting onto some of the ridgetops around
daybreak. This is very similar to what we have seen the last
several mornings. Visibilities and temperatures are about an hour
behind yesterdays pace, so only change was to go about an hour
slower with the onset of the fog tonight in the TAFS. Otherwise,
expect fog to burn off by 14z again with VFR conditions returning.
Fog will be possible again Monday night, with fog developing after
03z, but not impacting TAFS until after 06z. Light winds are
expected through the period.




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