973
FXUS63 KJKL 101556
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1156 AM EDT Mon Jun 10 2024

.KEY MESSAGES...

- Slightly cooler than normal and pleasant weather will hold
  through mid-week.

- Hot weather arrives late this week, with highs in the upper 80s
  to lower 90s taking hold by Sunday.

&&

.UPDATE...
Issued at 1156 AM EDT MON JUN 10 2024

The morning surface analysis shows a weakening cold front is
entering the northern parts of the state this late morning hour.
This does have a notable mid- and upper level trough seen in the
forecast fields and water vapor satellite layers. In the wake of
this, there is some lower stratus noted in the upper Ohio Valley
and therefore opted to increase our sky cover some this afternoon
because of this. The HREF and some other guidance show this will
mix out and dissipate, but this seems to be holding on longer than
thought by the guidance. Given this leaned toward the short term
blended model guidance that seemed to have a little better handle
on the trends in sky cover. Also, some CAMs want to suggest a few
showers develop along and near the cold front, but overall this
looks unlikely at this point and NBM hourly PoPs don`t reflect
this either. Therefore, will just keep it sprinkles as previous
forecast already added.

UPDATE Issued at 918 AM EDT MON JUN 10 2024

Obs and satellite data are showing much of the fog has lifted to
more a low stratus/vertical visibility type issue. Therefore, we
let the Dense Fog Advisory expire. Outside of this only minor
changes were needed to update the forecast with the latest obs and
trends.

UPDATE Issued at 730 AM EDT MON JUN 10 2024

The fog is dissipating on track this morning and should be clear
everywhere by 9 am. Have tweaked the forecast with the inclusion
of the latest obs and trends for the T/Td/Sky grids with this
update. These minor adjustments have been sent to the NDFD and web
servers.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 410 AM EDT MON JUN 10 2024

07Z sfc analysis shows high pressure nosing into the area from
the west, though cyclonic flow remains for the northeast parts of
the state related to a low over New England and a secondary cold
front north of the Ohio River. This has allowed for temporary
clearing through the JKL CWA which, when combined with the
moisture left behind from the southern rains of Sunday, has led to
the development of fog through the Cumberland River valley -
becoming locally dense in the valleys of the lesser tributaries.
For this reason, an SPS is in effect until 13Z. Otherwise,
temperatures vary from the low to mid 50s in the valleys to the
lower 60s on the ridges. Meanwhile, amid light winds, dewpoints
are generally in the low to mid 50s.

The models, and their individual ensemble suites, continue to be
in pretty good agreement aloft through the short term portion of
the forecast. They all depict the western extent of a deep
Northeast trough at 5h pivoting south into eastern Kentucky today
and tonight. This will bring with it some height falls and an
ample amount of mid level energy - with the most distinct impulse
moving through this evening. The passage of this particular wave
will also mark the 5h trough axis clearing the area allowing for
gradually rising heights and a lessening of the energy in the
weaker northwest flow that remains at mid levels. The model
spread is again quite small so that the NBM was used as the
starting point for the short term grids along with the
incorporation of standard terrain distinctions for temperatures
tonight.

Sensible weather features a mostly dry and pleasant couple of
days - once the fog clears this morning. Cooler temperatures and
lower humidity will be a nice way to start the week - especially
considering the heat to come later in the forecast. We will see a
very small chance for a shower in the northeast parts of the JKL
forecast area this afternoon and early evening on account of a
secondary cold front pushing through the region and lowering
heights/energy aloft - though most places will stay dry or see
just a few sprinkles. The clouds associated with that boundary
clear out tonight setting up a good night for radiational cooling
with many valley spots seeing temperatures as low as the mid 40s
by dawn Tuesday - along with typical river valley fog formation
that becomes locally dense late. Tuesday will be the best day of
the bunch with more in the way of sunshine and temperatures still
on the cool side along with comfortable humidity levels.

The main changes to the NBM starting point consisted of adjusting
the temperatures in order to better represent terrain detail in a
radiational cooling situation. PoPs were low through the period
and only tweaked a notch higher for the northeast with peak
heating this afternoon.

.LONG TERM...(Tuesday night through Sunday)
Issued at 451 AM EDT MON JUN 10 2024

Seeing better than usual agreement in the pattern aloft among the
operational models through Dy6, Sat with some minor divergence in
the solutions thereafter. Ensembles are quite similar with the
overall pattern as well. We begin the extended in the middle of a
transition of a retreat of the core westerlies northward along the
Northern Tier. The pattern aloft then amplifies again with a mean
troughing developing over the west coast and ridging across the
eastern CONUS by the end of the forecast window. Amplified heights
across the Great Plains does help induce some troughing over the
Great Lakes by Friday as some short wave energy dives southeast
into the Upper Ohio Valley. Ridging then strengthens and shifts
eastward into the eastern CONUS through the remainder of the
period.

Sensible weather features generally dry, fair weather. The
aforementioned trough moving through the Great Lakes on Friday
will drop a surface cold front into the Ohio Valley. This surface
front just does appear to make it into eastern Kentucky before
stalling out due to the lack of support aloft. With better
dynamics further north, there is little in the way of the
opportunity of rain. There are some minor PoPs across northern
portions of the forecast area. Depending on what guidance one
prefers, the front either lifts back to the northeast and/or
dissipates. Strong ridging aloft then exerts its control for the
remainder of the forecast.

Main concern through the period will be heat towards the end of
the period. With strong ridging aloft and surface high pressure
building into the southeastern CONUS, temperatures will be quite
warm. Ensemble solutions do show a high probability (50-60%) of
H850 temps climbing to between 18-20 C. This will drive
temperatures up to around 90 by the end of the week and into the
weekend. With a gradual and eventual influx of moisture into the
area, heat indices will climb to near or around 100 degrees by the
end of the period. However, with the moisture will come an
increase in PoPs as well, but more likely just beyond the end of
the current forecast window.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 755 AM EDT MON JUN 10 2024

The fog is clearing out on track this morning - or a little ahead
of time. After this, VFR conditions will prevail today with
scattered to broken cumulus at around 5 kft by mid-afternoon with
a potential for a few sprinkles or a stray shower around. Look for
mostly clear skies tonight with another bout of valley fog late at
night into Tuesday morning. Light winds are expected through this
morning, with west-northwest ones developing in the afternoon
peaking at generally 10 kts or less with max gusts of around 14 to
17 kts.

&&

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

$$

UPDATE...DJ
SHORT TERM...GREIF
LONG TERM...RAY
AVIATION...GREIF