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000
FXUS63 KJKL 180115 AAB
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
915 PM EDT Wed Apr 17 2024

.KEY MESSAGES...

- A dying cold front move into the area tonight and could bring a
  few showers/thunderstorms to our northeastern counties.

- A cold front with more momentum will approach Thursday night and
  pass through on Friday, presenting at least a likelihood (>= 60%
  chance) of showers/thunderstorms.

- Cooler and more seasonable temperatures will arrive behind the
  second cold front and carry through the middle of next week.

&&

.UPDATE...
Issued at 915 PM EDT WED APR 17 2024

A weak moisture starved cold front is sagging southeast toward
eastern KY and should cross the area overnight. There is mainly a
change in moisture behind it with upper 40s to low 50s dewpoints
behind it an dewpoints in the upper 50s to low 60s ahead of it.
Convection is occurring well north east of eastern KY at this
point and although a stray shower or two is possible near the
boundary overnight, chances are too low to go more than 10 for the
remainder of the night. Hourly grids were updated based on recent
observations and trends.

&&

.SHORT TERM...(This evening through Thursday night)
Issued at 436 PM EDT WED APR 17 2024

A cold front was situated over western OH and southern IN late
today, with thunderstorms occurring along/ahead of the front in
OH. The front`s upper level support is moving east across the
Great Lakes, north of our area, and the front will lose momentum
and definition as it arrives in KY tonight. Forecast soundings
show some potential for a cap to be broken this evening, but model
QPFs and MOS POPs are low. Have used just a 20 percent POP in our
far northeastern counties.

Ridging at the surface and aloft then moves in from the west
overnight and passes to our east on Thursday, resulting in fair
wx.

An upper low traveling east over southern Canada will support
another cold front which will approach us from the west northwest
late Thursday night, with weak low pressure traveling along the
front as it approaches. Models agree on showers and possibly
thunderstorms arriving ahead of the front late Thursday night.

.LONG TERM...(Friday through Wednesday)
Issued at 608 PM EDT WED APR 17 2024

A mean zonal flow best describes our pattern through the extended
portion of the forecast. Within that pattern there are three main
features of interest, the first being short wave energy
transiting the Great Lakes Friday night through Saturday, which
has little if any impact on our sensible weather other than some
increased cloud cover. The second is shortwave energy/trough
passing through the OH/TN valleys Sunday through Sunday night. The
third is a trough rotating through the Midwest at the end of the
forecast window.

Sensible weather features a wet start to the period as a cold
front will be passing through eastern Kentucky Friday. Widespread
showers and scattered thunderstorms in the morning will taper off
to isolated activity by late in the day and early evening.
Based on the timing of this system through eastern Kentucky
Friday, it would appear MLCAPE ~700 J/kg and marginal effective
shear (~25 kts) will not be enough to provide any type of
hazardous threat to the area. Much of the better environmental
instability and shear will be located to our southeast outside of
our forecast area. We are looking at perhaps a widespread half
inch of rainfall with this first round of weather.

Our next best chance for rain thereafter will be the trough
passing through the lower Ohio and TN valley Saturday night into
Sunday. A surface low will develop in response to this second
system, and will provide a chance of showers to the southeastern
zones of our forecast area. There are no hazards with the second
round of weather, with no forecasted thunderstorms and on average
less than a tenth of an inch of rainfall expected. However, this
system will carry enough moisture out of the area, and pull in
enough dry air into eastern Kentucky that temperatures Monday
morning are expected to fall into the upper 30s. Model guidance
suggests temperatures may be able to drop a bit further, possibly
into the mid 30s by Monday morning. Thus some patchy frost could
not be ruled out for Monday morning.

The final system of interest will be the a storm system that will
bring another round of precipitation to the area in the form of
scattered showers and thunderstorms at the end of the period. It
is likely this system will bring another reinforcing shot of
cooler air into the region just beyond the end of the forecast
window. At present PoPs are low (averaging 30% or less) and QPF is
light, around a tenth of an inch or less.

Temperatures will be around normal or just below, providing some
seasonably cool weather, and generally more clouds than not. The
best chance of seeing sunny, dry and pleasant weather will be
Monday through Tuesday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 830 PM EDT WED APR 17 2024

VFR was observed across most of the region at issuance time, though
MVFR was observed near portions of the TN and VA border.
Improvements to VFR areawide are expected through 03Z with dry
weather overnight. Some fog may develop with reductions to MVFR
and at least IFR, especially in the valleys, by the 04Z to 06Z
timeframe and this could affect a few of the TAF sites including
KSME, KLOZ, and perhaps KSYM. Southwest to west winds will prevail
during the first 12 hours of the period with sustained speeds and
gusts diminishing to around 10KT or less through 04Z. After 12Z,
south to southwest winds will prevail as a cold front begins to
approach. Convection associated with it should hold off until
after the period and following the dissipation of fog by 14Z, VFR
should prevail again areawide.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...JP
SHORT TERM...HAL
LONG TERM...RAY
AVIATION...JP