Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 222315

Area Forecast Discussion
National Weather Service Louisville KY
615 PM EST Sun Jan 22 2017

...Updated Aviation Discussion...

.Short Term (Now through Monday Night)...
Issued at 330 PM EST Sun Jan 22 2017

The tornado outbreak over the southeast U.S. has captured not only
the attention of the meteorological community today, but most of
the energy in the atmosphere over the eastern U.S. as well.  Only a
lone less-than-impressive band of showers along the Ohio River
exists north of north of the surface low responsible for the
southeastern severe weather.

The latest high resolution guidance confirms the current trends
in our region, with only the Ohio River showers lingering through
the evening, then weak shower development overnight across the
eastern half of the area as the low moves due east toward
Georgia/South Carolina.  Weak showers will then end from west
to east on Monday and Monday evening.

The large hole in the clouds currently over the southern half of KY
was today`s unscheduled bonus.  Unfortunately, it will quickly
come to an end this evening as high clouds spreading north from the
southern storms were already through most of Tennessee and starting
to fill it in from the south.  Once this is accomplished, overcast
skies will prevail until tomorrow night, when some clearing will
start in the west.

With the clouds and tightly wrapped circulation around the
surface low tonight, temperatures will remain very mild overnight,
only falling to the mid 40s to lower 50s.  On Monday, as the low
moves east, winds will become more northerly and with gusts over 20
mph, will easily push colder air into the region.  High temperatures
will only be perhaps 5 degrees warmer than the morning lows, and
many locations will see temperatures falling during the afternoon.

Monday night will usher in a return to more seasonal temperatures,
as lows dip into the 30s to around 40.

.Long Term (Tuesday through Sunday)...
Issued at 405 PM EST Sun Jan 22 2017

The main weather highlight in the long term continues to be a return
to near normal temperatures later in the work week.

After brief ridging and dry weather on Tuesday, a fast moving upper
level low will race from the central plains through the Great Lakes
on Wednesday.  A surface cold front associated with this system will
follow along the broad, positively tilted trof trailing the low. As
the front moves through the Ohio Valley Wednesday, temperatures more
in line with late January will return to the region.  The mid range
models all indicate a few light showers with the FROPA Wednesday,
but with no clear dynamics, have only included low POPS for the
eastern part of our area, and then only due to orographic forcing.

Some light showers are also indicated by low POPS across the
northeast part of our forecast area as a secondary surge of colder
air comes in Thursday with a short wave following the main trof.
Given the temperatures in place for this one, some of the showers
could fall as flurries, but no accumulation is expected at this

High temperatures will be in the 50s Tuesday and Wednesday, with 60s
south and east ahead of the front Wednesday.  For the remainder of
the week and into the weekend, the low 40s will be the warmest
anyone will see.

Low temperatures in the 40s Wednesday morning will be replaced by
the 30s Thursday morning, and the 20s after that.


.Aviation (00Z TAF Update)...
Issued at 610 PM EST Sun Jan 22 2017

Upper low passing to our south will become stacked with a deepening
sfc low lifting toward the Tennessee Valley overnight and pull it
well to our east on Monday. Deep easterly flow in the mid/upper
levels and strong low-level cold advection will result in frisky N-
NE winds and low ceilings for much of the valid TAF period, with
very limited confidence in the evolution of the precip shield.

Forecast confidence is highest at LEX, where showers already
starting to develop over eastern Kentucky will spread in later this
evening, and take ceilings down to IFR by midnight. Will see
fluctuations in ceiling and vis, but only included TEMPO for LIFR
cig/vis for a few hours Monday morning.

Not as confident in the precip spreading westward into SDF and BWG,
but still expect ceilings to drop to fuel-alternate after midnight
tonight. Spiral bands will likely spread west off the main low at
times, but likely be dissipating as they get into SDF and BWG. Will
limit the mention to VCSH for SDF, but will carry prevailing -SHRA
for BWG closer to the upper low. Visibilities likely to be MVFR in
the rain, but won`t change the flight category so will not get too
cute with that.

One aspect where confidence is high across the board is that it will
be windy. Tightening pressure gradient will crank winds up out of
the NNE this evening, with a solid 12-15 kt and gusts near 20 kt.
During the day on Monday, expect sustained 15 kt with gusts close to
25 kt, and a gradual backing to NW.




Short Term........JBS
Long Term.........JBS
Aviation..........RAS is the U.S. government's official web portal to all federal, state and local government web resources and services.