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Area forecast discussion...updated
National Weather Service Jackson Kentucky
651 PM EST Tue Jan 23 2018

Update...
issued at 651 PM EST Tuesday Jan 23 2018

The forecast is on track. Merely freshened up the hourly
temperatures and dew points into this evening based on the latest
trends in observations.

&&

Short term...(this evening through Wednesday night)
issued at 415 PM EST Tuesday Jan 23 2018

A shortwave trough was moving through the eastern Great Lakes and
Ohio Valley and into the Appalachians this afternoon while a
shortwave ridge was over parts of the MS valley with another
shortwave upstream over the plains. Cumulus and stratocumulus was
well entrenched over the lower Ohio Valley, MS valley, and Great
Lakes. Some radar returns are upstream over parts of in and
central Kentucky where mainly sprinkles or flurries are possibly
occurring.

Short term model guidance such as the hrrr brings a shortwave
trough/500 mb vort Max across the region this evening and an
associated surface trough. Cold advection is continuing with the
coldest air with this airmass anticipated late tonight and into
the day on Wednesday as the second upstream shortwave trough moves
through. Moisture is expected to remain at the low levels near
and below 850 mb and low clouds should persist through at least
Wednesday evening. The trough departs to the northeast on
Wednesday night with mid level heights rising across the southeast
and into the lower Ohio Valley and Tennessee Valley regions.

Omega peaks on time height sections this evening and again on
Wednesday morning to early afternoon as the two shortwaves move
through when rain or snow shower or flurry or sprinkle activity
should peak. After early this evening, the atmosphere should be
sufficiently cold enough for either isolated snow showers or
flurries.

With the 850 mb temperatures in the -5c to -10c range and cloud
cover anticipated, below normal temperatures are expected for
highs on Wednesday. Skies should gradually clear on Wednesday
night, but NAM guidance suggests clouds should linger the entire
night. If skies were to remain mostly clear to clear the valleys
in the Cumberland vally could end up around 20 or the upper teens.

Long term...(thursday through tuesday)
issued at 257 PM EST Tuesday Jan 23 2018

The extended will start off with a period of warm and dry weather to
end out the week and into the upcoming weekend. A ridge of high
pressure will prompt south to southwest winds which in turn will
transport warm air off the Gulf of Mexico into the Tennessee and
Ohio Valley regions. The next chance of rain for eastern Kentucky
will arrive in the area late Friday night, as a cold front
approaches from the plains. The trend in the latest model data is
for a faster west to east progression of this weekends weather
system, and the forecast will reflect this. Rain showers should
gradually overspread the area on Saturday, and will be most
widespread from Saturday evening through Sunday evening, as a cold
front moves across the region. The precipitation will taper off
Sunday night, as the front moves further from our area. Temperatures
should fall to the point where some snow will mix with the rain
Sunday night. Flurries and a few snow showers are then expected
across the area from around dawn on Monday through early Monday
morning. Any remaining precipitation should be exiting the area by
late Monday morning. After that, the weather should be dry across
eastern Kentucky through Tuesday.

Temperatures in general should be above normal in the extended.
Daytime highs should be in the 50s Friday through Sunday, with
nightly lows ranging from the mid 30s through the lower 40s Friday
night, and in the lower 40s for Saturday night. These two warm
nights are expected to be sandwiched by two colder nights when
temperatures will be in the upper 20s and lower 30s(fri night and
sun night).

&&

Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 651 PM EST Tuesday Jan 23 2018

Ceilings will lower to MVFR from west to east through this
evening, as an upper level disturbance moves across the Ohio
Valley. Some light rain/snow showers may be seen at times this
evening; however, expect this activity to remain light enough to
not cause much in the way of visibility restrictions.
Precipitation will taper off later tonight, with MVFR ceilings
likely hanging on through the rest of the period. West winds of
around 10 kts, with a few gusts of 15 to 20 kts at times through
early this evening, will gradually diminish overnight and into
Wednesday.

&&

Jkl watches/warnings/advisories...
none.
&&

$$

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