Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 180855

National Weather Service Jackson KY
355 AM EST Wed Jan 18 2017

.SHORT TERM...(Today through Thursday)
Issued at 355 AM EST WED JAN 18 2017

08z sfc analysis shows a cold front departing to the east while
high pressure builds in from the west. However, plenty of low
level moisture remains in place and, along with the passage of a
compact upper trough to the northeast early this morning, this is
keeping the cigs low and a potential for drizzle or sprinkles in
the forecast through dawn. Temperatures remain mild overnight for
this time of year with readings varying from the low 40s northwest
to the lower 50s in the southeast. Dewpoints are not far off from
the dry bulb temperatures - just a few degrees lower in most
places. Meanwhile, winds are from the northwest to west at 5 to
10 mph with occasional gusts to 15 mph. Patchy fog also is found
through the area early this morning.

The models are in better agreement aloft than last night as they
all depict a sharp trough - with minimal spread - diving into the
Central Appalachians from the northwest early this morning. This
is followed by a quick shot of ridging today and renewed deep
layer southwest flow later tonight and Thursday in the face of a
deep and broad closed low over the High Plains. In this flow, a
lead batch of energy will lift into the Tennessee Valley early
Thursday with more support and height falls arriving by evening.
Given the better model agreement will favor a blend, though with a
strong lean toward the HRRR in the near term.

Sensible weather will feature patches of sprinkles and drizzle
around this morning before a lull for drying sets up later today
and tonight as high pressure passes quickly over the area. The
next system then approaches from the southwest late tonight
pressing into the Cumberland Valley on Thursday. All the while
warm weather continues so that all pcpn will continue to be only
in the form of rain across eastern Kentucky through the short
term and well beyond.

Again started with the CONSShort and ShortBlend for most elements
through the short term portion of the forecast - making only minor
adjustments to the low temps tonight. Also, adjusted PoPs to
spread the next round of pcpn in a bit quicker and slightly more
extensively on Thursday than suggested by the CONSShort.

.LONG TERM...(Thursday night through Tuesday)
Issued at 245 AM EST WED JAN 18 2017

The models overall were in good agreement once again in the
extended, with a few timing differences here and there and the ECWMF
being a bit slower than the GFS. That said, the general consensus is
for a series of low pressure systems aloft to move across the Ohio
and Tennessee valley regions this weekend into the first of next
week. Each of these systems will bring a good chance of rain to
eastern Kentucky, with the potential for moderate rainfall from time
to time. We should see a break in the action Friday night and
Saturday, before things ramp up again Saturday night and Sunday. The
first round of rain is slated for Thursday night and Friday, as a
well developed area of low pressure moves out of the southern
Mississippi valley and across the Tennessee and Ohio Valleys. The
second round of rain is expected Saturday night and Sunday, as a
warm front, associated with an area of southern Plains low pressure,
makes its way northward across our area. This boundary will likely
bring only scattered showers to the area initially, with the
activity forming well ahead of the boundary. Once the front moves
closer to and across our area early Sunday morning, we should see
numerous rain showers through out the morning. The activity should
taper off again by Sunday afternoon, after the front moves to our

The main shot of rain is expected from late Sunday afternoon
through late Monday, as a strengthening, and therefore slow
moving, area of low pressure ejects out of the southern Plains and
across the lower Tennessee valley region. The models begin to
diverge here slightly, with the GFS depicting a split of energy,
with an area of low pressure breaking off from the main low Monday
and Monday night and slowly moving toward the eastern Great Lakes.
The ECWMF, no the other hand, tries to keep the southern Plains
low more consolidated as it moves across the region. The end
result is still going to be widespread rainfall across the area
from this weekend through the beginning of next week. A third
weather system may bring some scattered showers back to eastern
Kentucky by Wednesday.

Temperatures during the period will be well above normal, with daily
highs in the 60s expected over the weekend, and daytime maximums in
the 50s the first couple of days of the new work week. Nightly lows
will generally be in the 40s, with a few locations perhaps seeing
lows around 50 Friday and Sunday mornings.


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

Lingering VFR ceilings around the area will return to MVFR and
eventually IFR during the early morning hours. A compact upper
wave will move past to the northeast by dawn and this should
encourage a few light rain showers or sprinkles to develop across
the area - particularly north and east of JKL. IFR ceilings will
then gradually improve to MVFR - eventually VFR - from southwest
to northeast during the day Wednesday, as high pressure builds
overhead. West southwest winds of near 10 kts, will become more
out of the west as the cold front exits to the east. Then look for
winds to diminish to around 5 kts or less by evening.




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