Area Forecast Discussion
Issued by NWS Jackson, KY
FXUS63 KJKL 280741
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
341 AM EDT Wed Sep 28 2016
.SHORT TERM...(Today through Thursday)
Issued at 340 AM EDT WED SEP 28 2016
The large upper level low continues to gradually sink southward
from the Great Lakes region towards the Ohio Valley this morning.
The process of this low reaching Kentucky has actually slowed down
a bit in models, delaying further the increase in sky cover and
rain chances this afternoon. In fact, high-res models bring
rain/storms into the far northern counties closer to 21Z. The
models then develop a convective linear feature along the cold
front as it pushes further into our area closer to 00Z Thursday.
The best chances for thunderstorms, including some small hail and
strong winds (with about 900 DCAPE) will likely be contained to
the far northern counties during the late afternoon period. But
since the frontal passage will take place mostly outside of peak
heating late this evening, thunderstorms shouldn`t pose much of a
threat for the majority of the area. Shower chances will then
continue through Thursday evening as the upper low continues
moving over Kentucky. Thunderstorms will again be possible
Thursday afternoon and evening with ample upper level dynamics and
modest instability in the area.
Due to clear skies and dry air in place, lows this morning are
expected to dip into the upper 30s in the deepest valleys and in
the low and mid 40s elsewhere. Even with the dry air in place,
some fog is possible in the deeper valleys and near bodies of
water this morning. Afternoon temperatures should be near average
today, in the mid 70s. But this will depend on how quickly the
cloud cover increases this afternoon. Low temperatures tonight
will be closer to normal (around 50 degrees) with overcast skies
and showers in the area. Thursday will be on the chilly side with
highs only in the low and mid 60s.
.LONG TERM...(Thursday night through Tuesday)
Issued at 326 AM EDT WED SEP 28 2016
A blocky long wave pattern will be in full swing across the CONUS
through the weekend. Starting out, an upper level low will be
entrenched across the Ohio and Tennessee valleys, with ridging
across the Plains, while troughing works in across the West Coast.
The models have maintained fairly good continuity, gradually
shunting the upper level low back to the north towards the Great
Lakes, as the ridge slowly slides east towards the Mississippi
Valley, and troughing becomes more established across the western
CONUS. Model differences in timing and amplitude become more
apparent by early next week, as the trough swings east into the
Cool conditions, along with a threat of some showers, and perhaps
a few storms during peak heating, will continue across eastern
Kentucky to end the work week. Depending upon the exact position
of the cutoff low and an associated dry slot, Friday may be
drier than currently forecast, as depicted by the latest ECMWF.
The last of the showers will end by late Saturday afternoon, as
the low pulls far enough away, and heights recover. Dry weather
will ensue Saturday night and looks to last into early and
perhaps middle of next week, depending on the amplitude of the
ridge. Temperatures will gradually warm up across eastern
Kentucky through early next week, with a few 80s for highs
returning by next Tuesday.
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 200 AM EDT WED SEP 28 2016
VFR conditions should remain in play through most of the period.
Clear skies along with light winds through much of the night will
lead to valley fog overnight into Wednesday morning. Have kept any
visibility reductions out of the TAFs as dewpoints were able to
mix into the upper 30s to low 40s this afternoon. Cloud cover will
be on the increase from the northwest tomorrow as an upper level
disturbance and associated cold front approach eastern Kentucky.
Additionally, SYM will have a chance at seeing some nearby showers
by late morning/early afternoon. Rain chances will be slightly
less farther south and will also arrive a little later in the day.
Ceilings will begin to develop through the afternoon, and then
gradually lower to almost minimums by the end of the TAF forecast
period. Fog may also be a factor late Wednesday night depending
on shower activity. Winds will be gusty tomorrow ahead of the
front, up to 20 knots, then gradually diminish overnight to
around 5 knots or less.