157
FXUS63 KJKL 080320 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1120 PM EDT Sun Sep 7 2025

.KEY MESSAGES...

- Below normal temperatures and dry weather will persist through
  Monday.

- Temperatures will gradually warm to near normal for later in
  the week with no rainfall expected.

&&

.UPDATE...
Issued at 1120 PM EDT SUN SEP 7 2025

No significant changes were made to the forecast with mainly just
the inclusion of the latest obs and trends for the T/Td/Sky grids.
These minor adjustments have been sent to the NDFD and web
servers along with a freshening of the zones and SAFs.

UPDATE Issued at 730 PM EDT SUN SEP 7 2025

23Z sfc analysis shows high pressure in firm control of the
weather over eastern Kentucky. This is keeping the winds settled
and is working to clear the skies. Currently, temperatures are
running in the mid to upper 60s with some near 60 degree reports
in the sheltered valleys. Meanwhile, amid light and variable
winds, dewpoints are generally in the low to mid 50s. Have updated
the forecast mainly to add in the latest obs and trends for the
T/Td/Sky grids. These minor adjustments have been sent to the NDFD
and web servers along with a freshening of the zones and SAFs.

&&

.SHORT TERM...(This evening through Monday night)
Issued at 303 PM EDT SUN SEP 7 2025

Thermometers are rising into the lower and mid 70s across most of
eastern Kentucky at mid-afternoon under some puffy fair-weather
cumulus. While the incoming airmass is quite dry (dew points are
in the 40s to low 50s across most areas), the latest surface
analysis does show a weak surface trough dropping south of the
Ohio River and that may encourage the cumulus to be a little
deeper over the north. The primary driver of our weather, though,
is a seasonably strong surface high off to our west with its ~1026
mb center over northern Iowa.

The subtle surface trough will fill in this evening as the
aforementioned surface high drifts eastward, cresting north of
Cincinnati overnight before lifting northeast across the Lower
Great Lakes and into New England on Monday/Monday night. As the
high passes, dry northwesterly flow over eastern Kentucky this
afternoon will slowly veer northeasterly to easterly on
Monday/Monday night. This will help keep the typical nighttime
valley fog confined mainly to the sheltered mainstem river valleys
tonight. Also, with PWATs not far from 0.5 inch on Monday,
relatively little in the way of even a cumulus field is expected
to develop -- nearly full sunshine should prevail. Fog is likely
again Monday night, though again primarily in the sheltered river
valleys.

In sensible terms, temperatures are near daily highs and will drop
off quickly as the sun sets. Look for low temperatures ranging
primarily in the 40s. A few of the coldest northern hollows could
dip to right around 40F. Expect areas of fog to form in the
sheltered river valleys. Looking ahead to Monday, sunshine will
prevail after any valley fog burns off. Temperatures should top
out in the mid 70s for most. Finally, look for fog to develop once
again in those favored valley locales on Monday night; otherwise,
clear skies and light winds will allow temperatures to settle
back into the mid 40s to lower 50s. A few of the coldest hollows
could briefly dip into the lower 40s.

.LONG TERM...(Tuesday through Sunday)
Issued at 446 PM EDT SUN SEP 7 2025

The GFS and ECMWF are in general agreement for our area through
the upcoming weekdays. The upper level trough currently over the
eastern CONUS will have retreated north and progressed eastward by
the time the long term period starts, leaving very weak flow aloft
over our area ahead of a weak trough approaching from the
northwest. Surface high pressure will be centered over New
England, but still ridging southwestward along the eastern slopes
of the Appalachians.

Some form of the ridge is expected to remain in place near the
eastern slopes of the central and southern Appalachians during the
long term period. This will prevent any significant low level
moisture advection into the area, keeping our lower levels dry.
Aloft, the aforementioned trough will pass over in the Wednesday
night/Thursday time frame and be departing to the east on Friday,
but it is not likely to have any impact. Even though no
substantive lower level temperature advection will occur, a very
gradual warming trend can be expected during the workweek as
insolation acts on the air mass on a daily basis.

The GFS and ECMWF still fall into disagreement next weekend. The
ECMWF brings a trough currently near the Aleutians eastward to
Hudson Bay and then southward as a closed low to the Great Lakes
during the weekend, forming the eastern side of an omega block.
Meanwhile the GFS keeps the wave well to the north, continuing to
move across Canada. This puts the two deterministic runs of these
models completely out of phase over the Great Lakes and lower
Ohio Valley next weekend. With our atmosphere still lacking
significant moisture, even in the ECMWF, the main effect during
the weekend would be on temperatures. The lower geopotential
heights of the ECMWF would favor the warming trend to stagnate,
with near seasonal temperatures next weekend. The building ridge
of the GFS would favor above normal temperatures. Will wait for
model agreement to see what is most likely to transpire, realizing
that the current model blended forecast may change.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 800 PM EDT SUN SEP 7 2025

VFR conditions are noted area-wide at issuance and are expected
to generally prevail at the TAF sites. A high-base cumulus field
at about 5-6kft AGL and will gradually dissipate this evening with
the loss of daytime heating. Overnight, fog is expected to
develop in the typically favored sheltered valley locales with
locally IFR or worse conditions. While a few wisps of fog cannot
be entirely ruled out at the TAF sites, the fog should largely be
confined to the more sheltered valleys. All fog will clear out
Monday morning shortly after sunrise leaving VFR conditions
behind for all. Winds will remain variable to northerly at around
5 kts or less through the TAF window.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...GREIF
SHORT TERM...GEERTSON
LONG TERM...HAL
AVIATION...GEERTSON/GREIF