Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 211950

National Weather Service Jackson KY
350 PM EDT Wed Mar 21 2018

.SHORT TERM...(This evening through Thursday night)
Issued at 350 PM EDT WED MAR 21 2018

19z sfc analysis shows deep low pressure exiting the area with
healthy cyclonic flow continuing through eastern Kentucky. These
winds are upslope and as a result are helping to sustaining snow
shower activity even as the low`s center is in the process of
jumping to the East Coast. Visibilities with these showers
remain between 1 and 2 miles - still impacting the area and likely
accumulating a bit. Currently brisk northwest winds are running
at 10 to 15 mph with gusts to 25 mph. The CAA on those winds,
along with overcast conditions and snow showers, have kept
temperatures from climbing too far out of the lower 30s across
the area today. Meanwhile, dewpoints are similar to temperatures -
generally in the upper 20s to lower 30s. Wrap around snow showers
associated with the now coastal low are being enhanced by the
upslope flow in the far east supporting some light accumulations
this afternoon. Accordingly, will keep the WSWs running through
00z for the entire area, though we may be able to clear the
southwest before too long.

The models are in good agreement aloft through the short term
portion of the forecast. They all depict the deep trough that will
run up the East Coast tonight. Trailing energy will exit Kentucky
in northwest flow by Thursday morning. Height rises will follow
as strong ridging starts to work east out of the Rockies and into
the Plains. However, before this can influence the weather over
Kentucky much, another short wave will ride southeast out of the
northern Great Lakes region and brush by the area to the northeast
early Friday morning - maintaining the strong northwest flow at
mid levels. Given the good model agreement have favored a general
blend with a lean toward the higher resolution HRRR and NAM12 for

Sensible weather will feature snow showers gradually winding down
this evening from west to east with accumulating snow expected to
be done toward 00z when the WSWs will likely be allowed to drop.
Following the snow showers dissipating, clouds will break up from
west to east late. CAA and radiative cooling tonight should send
readings down into the lower and mid 20s by dawn Thursday. Any
left over wet patches or slush on the roads tonight will likely
refreeze and create localized black ice conditions. Have messaged
this in the HWO and will make sure it is highlighted in the
evening weather story, as well. Sunshine and high pressure will
bring warmer temperatures to the area on Thursday drying us out
and taking care of most of the snow on the ground. For Thursday
night, the high will shift far enough east to allow some lower
clouds to return to the southwest parts of the area in the form
of a developing warm front. Otherwise, expect mostly clear skies
to also support a decent ridge to valley temp split overnight
outside of the Cumberland Valley.

Did make minor adjustments to temperatures tonight to go colder
in the places that have deeper snow cover and also due to CAA
affects on terrain. Likewise, adjusted temperatures Thursday
night for relative elevation differences away from the southwest
parts of the area. As for PoPs, lingered them a bit longer and
higher in magnitude through the evening and into the early
overnight hours in the east.

.LONG TERM...(Friday through Wednesday)
Issued at 305 PM EDT WED MAR 21 2018

The extended period will feature a mix of rain and snow to start
things off, as a couple of low pressure systems move across the
region over the weekend. The better chance of accumulating snow at
this time looks to be for the period Friday night into Saturday
morning. The latest model data indicates that the best chances for
accumulating snow will occur north of Highway 80. The second chance
for any snow will be Saturday night into Sunday morning, although
this shot of snow looks like it will be marginal at best with little
if any accumulations expected. Once the second weather system
departs the area late Sunday, we should see a period of dry weather
to begin the new work week. A ridge of high pressure should keep
precipitation associated out of most of the area until Tuesday
night. The ridge is then forecast to break down just enough to allow
an area of low pressure and its surface front to move across the
area on Wednesday. This system could potentially bring a good
soaking rain to eastern Kentucky.

Temperatures around the area should start off below normal, with
highs in the 40s and 50s expected Friday through Sunday. We should
see a return to normal temperatures on Monday, with highs that day
expected to max out in the mid to upper 50s. Next Tuesday and
Wednesday could see a return to well above normal temperatures, with
highs on both those days possibly topping out in the 60s. Nightly
lows should start off near or slightly above normal Friday and
Saturday nights, with above normal nightly lows on tap after that.


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

IFR/MVFR ceilings with light snow will continue across the area
through 21z, before gradually diminishing from west to east late
this afternoon and early evening. VFR conditions will then
eventually return into the early overnight hours into the day
Thursday, as high pressure builds in from the west. West to
northwest winds at 10 to 15 kts, with gusts of around 20 kts this
afternoon will diminish to less than 10 kts after dusk remaining
light through the night and before picking up again to near 10 kts
later Thursday morning.


Winter Weather Advisory until 8 PM EDT this evening for KYZ044-



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