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Area forecast discussion...updated 
National Weather Service Jackson Kentucky
813 PM EDT Tue Oct 25 2016

issued at 810 PM EDT Tuesday Oct 25 2016

Hourly grids have been freshened up based on recent observations
and trends. This led to no substantial changes at this time. High
pressure centered to the north and northeast of the area tonight,
mostly clear to clear skies, and light winds should set the stage
for valley frost formation or if not, lows near freezing for much
of valleys in southeastern Kentucky.


Short term...(this evening through Wednesday night)
issued at 450 PM EDT Tuesday Oct 25 2016

20z sfc analysis shows high pressure moving through the Ohio
Valley. This is providing mostly clear skies, aside from some high
clouds drifting through from the northwest. The cool high to the
north and good sunshine yielded temps ranging from the lower 70s
south to low 60s north this afternoon. Dewpoints, meanwhile, were
able to mix down into the low to mid 30s most places, but many
spots did see some 20s. The winds were generally light and
variable this afternoon.

The models are in good agreement aloft through the short term
portion of the forecast as they all bring a developing trough into
the Great Lakes by Wednesday evening. This will be accompanied by
a batch of energy passing through the Ohio Valley into Thursday
morning. The GFS is slight stronger with this feature than the
European model (ecmwf) and Canadian, but actual differences are relatively small.
Accordingly, a general model blend was preferred with a lean
toward the hrrr and nam12 and significant consideration given to
the dry air aloft (and co-op mos) that has been resulting in a
larger than forecast diurnal range of late for the area.

Sensible weather will feature another cool and mostly clear night
with light to calm winds. This will set the stage for chilly low
temperatures and likely areas of frost in the deeper valleys.
Patchy dense fog will again be found near the rivers late, as
well, helping keep those spots from seeing much in the way of
frost. The frost is anticipated to be a bit more widespread than
last night so have issued a frost advisory for our eastern 2/3rds
where radiational cooling will be maximized. More sunshine and
winds switching to the southwest will mean a warm day Wednesday
with low to mid 70s anticipated for highs. Attention will then
turn to the, unfortunately drying, cold front inbound for
Wednesday night into Thursday morning. Despite the withering of
the model quantitative precipitation forecast with this, there will be enough elevated instability
and dynamics aloft to yield a stray thunderstorm or two for
mainly northwest parts of the area overnight into Thursday
morning. Have included this in the grids and severe weather potential statement.

Again started with the consshort/shortblend for the bulk of the
grids with adjustments to the temps tonight and to a lesser extent
on Wednesday night revolving around terrain differences, as well
as knocking dewpoints down in the afternoon Wednesday. As for pops
- did bring them up into the slight chance range Wednesday night -
a bit higher than consensus MOS guidance - as the front starts to
press into the area.

Long term...(thursday through tuesday)
issued at 355 PM EDT Tuesday Oct 25 2016

An upper level trough axis will be swinging through the Great Lakes
at the start of the period, as a surface low tracks across the Ohio
Valley. An associated cold frontal boundary will move through the
area Thursday afternoon, bringing scattered showers and a slight
chance of thunder. The remainder of the extended period will likely
remain mild and dry with high pressure parked over the southeastern
Continental U.S..

High pressure will build into the region by Friday morning, allowing
for valley temps to drop off into the upper 30s/low 40s. However, a
quick return of warm air will take place Friday as the upper ridge
builds into the southeastern US. With the return flow in place,
temperatures should rebound into the upper 60s and lower 70s Friday
afternoon. Well-above normal temperatures are anticipated on
Saturday with most locations reaching the upper 70s, possibly eeking
out 80 degrees in spots. If we hit 80 degrees here at the Jackson
weather office, we will tie for the most 80 degree days in October
on record. As high pressure gradually shifts towards the Atlantic
Ocean Sunday through Tuesday, conditions will be dry as high
temperatures reach the mid and upper 70s each day with lows in the
upper 40s/low 50s. Tuesday may be another day that afternoon highs
reach 80 degrees.


Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 812 PM EDT Tuesday Oct 25 2016

Mainly VFR conditions and light winds will be experienced through
the period. Some patchy valley fog is expected from 5z to 14z
along the rivers, but this should not impact the taf sites. Clouds
will begin to thicken and lower ahead of a cold front late in the
period, but only high clouds and some mid clouds are expected.


Jkl watches/warnings/advisories...
frost advisory from 1 am to 10 am EDT Wednesday for kyz052-060-


short term...greif
long term...jvm

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