029
FXUS63 KJKL 160850
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
450 AM EDT Fri Aug 16 2024

.KEY MESSAGES...

- Humidity, along with the possibility of showers and
  thunderstorms, will increase Friday and last into Saturday night.

- Below normal temperatures are expected Sunday through Wednesday
  behind a cold front passage late Saturday night.

- Showers and thunderstorms will remain possible Sunday and
  Monday, especially in the afternoon and early evening, with a
  drying trend for Tuesday into Wednesday.

&&

.SHORT TERM...(Today through Saturday)
Issued at 450 AM EDT FRI AUG 16 2024

A slow moving mid/upper level low will move from the Upper
Midwest into the heart of the Great Lakes through the short term.
Pockets of short wave energy will round the bottom of the low as
it drifts eastward. Eastern Kentucky will reside in the left exit
region of a 40-50 kt mid-level jet today, with a 30-40 kt H850
LLJ jet nosing into the area by this afternoon. This will help
with lift across the forecast area today. However, extensive
cloud cover will tend to keep instability generally below 1000
J/kg through the bulk of the day. Shear will be marginal as well
at 25-35 kts. All said the severe threat looks marginal and as
expected SPC keeps eastern kentucky within a marginal risk for
severe weather. Consequently, the area could experience a few
strong storms and an isolated severe storm or two could not be
ruled out should any convection find itself residing within a
locally, more favorable storm environment. PWATs are reasonably
high, climbing to near 2 inches over much of the area and freezing
levels are relatively high at around 14 kft. But storm motions
are 20-25 kts or greater on average. Thus overall any hydro
threats look marginal and localized...and would more likely have
to be associated with training or repeated rounds of thunderstorms
should that occur. But even this type of scenario does not appear
particularly favorable at this time. With the expected timing of
convection and cloud debris post convection, muted afternoon
high temperatures across our east and southeast as compared to
model guidance. However, there could be some late afternoon
partial clearing and the chance for a substantial recovery of
temperatures does exist for the late afternoon time frame.

For the remainder of the short term, additional short wave energy
rotating around the upper low will pass through the Ohio Valley
tonight and then into the region again by late Saturday. Thus
after a lull in activity across eastern Kentucky through the late
this afternoon and early evening, convection may show a breif
period of enhancement late in the evening or overnight. It is
more likely that showers and thunderstorms redevelop late Saturday
with the help of late day heating as a more organized short wave
lobe tracks through the region. The surface front will be closer
to the area as well which will provide a better focus for
convection to fire. Instability and shear will be more favorable
for storms by late Saturday. However, lapse rates aloft are weak
and wind fields aloft are not as favorable for the lifting needed
for severe storms. Consequently, the severe threat will remain
marginal for late Saturday as well.

.LONG TERM...(Saturday night through Thursday)
Issued at 450 AM EDT FRI AUG 16 2024

The active weather in the above short term forecast package
persists through the first part of the long term forecast period.
This is in part due to the proximity of a well-defined upper level
low in the Great Lakes region. Forecast guidance generally agrees
that this low will dig into Ohio on Sunday before gradually
ejecting towards the Northeast in the early part of the work week.

The associated and ongoing convective activity on Saturday
evening will run its course into Saturday night, with PoPs peaking
earlier in the evening and then dwindling down overnight as
diurnal heating diminishes. However, the continued influence of
the aforementioned upper level low keeps showers and some
thunderstorms in the forecast for Sunday, especially across the
eastern portions of the forecast area and during the afternoon and
evening hours. Residual cloud coverage and lingering convective
debris will relegate CAPE values on Sunday to only marginally
supportive values. This is mirrored in the forecast afternoon
highs for Sunday, which are at or below the 80 degree mark. While
thunder chances do remain in the forecast, organized thunderstorm
potential thus appears to be much lower on Sunday than it was in
the short term forecast period. Rain, on the other hand, remains
in the forecast through Monday evening amidst favorable PVA aloft.

The back half of this particular long term forecast period looks
much quieter, driven by northerly flow aloft on the backside of
the departing upper level troughing and subsequent height rises.
Guidance once again generally agrees that a surface high pressure
system will settle into the Great Lakes by Wednesday and Thursday.
This will place Eastern Kentucky in a regime of northerly to
easterly winds at the surface. Flow aloft becomes notably weak in
this same time frame, favoring subsidence in the column.
Therefore, dryness becomes the theme of the forecast for Tuesday
and beyond. Efficient mixing diurnal processes should activate
given the quieter synoptics, as will the thermal effects of
localized terrain. Grid- wise, dewpoints were lowered below
standard NBM output in the afternoon hours and ridge/valley splits
were introduced in overnight low temperature forecasts.

Sensibly, it will feel great outside for most of next week! While
it might be a good idea to grab an umbrella or a raincoat on your
way out the door on Monday, you should be able to leave those at
home for the rest of the work week. Under mostly sunny skies,
afternoon high temperatures will slowly rebound to seasonable
normals, increasing a few degrees per day. On Monday and Tuesday,
highs will stay in the mid to upper 70s across the entire area.
After crossing the 80 degree threshold on Wednesday, expect the
warmest (mid to upper 80s) temperatures to occur just beyond the
end of the forecast period on Friday. Consequentially, the
development of some diurnal cumulus clouds appears possible on
Friday, but the lack of any significant synoptic forcing keeps
PoPs below the 15 percent mark. In short, Kentuckians should get
outside and savor the nice weather this week!

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 150 AM EDT FRI AUG 16 2024

VFR conditions are expected as a predominant flight condition
through the bulk of the period. However, guidance suggests there
could be some short periods of high end MVFR conditions, mainly
associated with showers and especially thunderstorms as a slow
moving surface cold front approaches form the west. There is one
cluster of storms currently passing through central Kentucky that
is moving towards, and may impact KSME and KLOZ during the first
few hours of the TAF period. Additional showers and thunderstorms
will develop on and off through the period and likely impact all
terminals at some point during the day Friday. FROPA is not
expected through the area until Saturday night into early Sunday,
or about 24 hours beyond the end of the current forecast window.
Winds will be light and variable, around 5 kts or less until after
sunrise, when a southwest gradient wind between 5-10 kts develops
ahead of the approaching cold front. Winds could be gusty in the
vicinity of any thunderstorms.

&&

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

$$

SHORT TERM...RAY
LONG TERM...MARCUS
AVIATION...RAY