Napfor, Kentucky Weather Forecast Discussion

823
FXUS63 KJKL 062036
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
436 PM EDT Sat Sep 6 2025
.KEY MESSAGES...
- Additional rounds of showers and thunderstorms will impact the
  area again today.
- Extensive fog is favored tonight and could become locally dense
  in some locations.
- Below normal temperatures and drier weather will return by
  Saturday night behind the cold front.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 300 PM EDT SAT SEP 6 2025
Regional radar imagery and surface observations show a fairly
steady light rain falling across nearly all of eastern Kentucky at
mid-afternoon. The back edge of the rain shield is noted from
roughly Vanceburg, KY southwest to Bugtussle, KY. Under this
rain, temperatures are cool, ranging from the upper 50s to lower
60s nearly everywhere except in the deep Cumberland Mountain
Valleys, where values as warm as ~70F are noted. The latest
surface analysis shows a cold front with an anafrontal structure
extending from New York City SSW to over southern Georgia. To our
west, surface high pressure reigns firm across the Central and
Northern Plains, outside of a couple of weak surface trough
features in the vicinity of the Upper Great Lakes. Aloft, a deep
and broad 500 hPa trough is in place over most of the CONUS east
of the Rocky Mountains.
This 500 hPa trough will linger aloft through the short-term,
though its core will become more displaced to the northeast. As a
result, that slow-moving surface cold front will edge southeast
through this evening, with most lingering precipitation tapering
by 21-22Z north of the Hal Rogers/KY-80 corridor. Further
southeast, patchy light drizzly rain could linger several hours
longer, perhaps even close to midnight over the higher mountains
along the KY-VA border. As the rain comes to an end at a given
location, skies will tend to lift and clear but this will be in
the evening or even after sunset for most locations. Due to
lingering low-level moisture and fairly weak winds, any clearing
should favor rapid fog formation, especially in sheltered valleys
and low-lying areas. However fog, may tend to lift into low
stratus overnight due to the thickening fog`s "insulative"
properties trapping outgoing long-wave radiation. A northeasterly
component in the weak near surface flow may also favor low
stratus. Looking ahead to Sunday, surface high pressure will shift
eastward, cresting north of the Ohio River Sunday night. The
drier air will manifest at the surface on Sunday after morning fog
and stratus lifts and scatters, allowing a fair-weather cumulus
field to develop. Quiet conditions persist Sunday night with fog
once again favored in the sheltered river valleys.
In sensible terms, look for light rain to diminish slowly from
the northwest this afternoon and evening. Temperatures should hold
close to current levels through sunset. Skies slowly clear from
the northwest as well this evening into the overnight, allowing
low stratus and extensive fog formation overnight. The fog could
become locally dense in some areas. It will be cooler with low
temperatures ranging from the mid 40s over the Eastern Bluegrass
to the mid 50s in the deep valleys near the Virginia-Kentucky
border. Otherwise, fair weather dominates Sunday and Sunday night
with high temperatures forecast to reach the low to mid 70s during
the afternoon while dew points settle into the 40s -- a splendid
early autumn day. Temperatures are then forecast to dip into the
40s area-wide Sunday night with fog redeveloping in the favored
valleys.
.LONG TERM...(Monday through Saturday)
Issued at 436 PM EDT SAT SEP 6 2025
A cool and dry air mass will still be in place locally to start
the period, as surface high pressure passes eastward over the
upper Ohio Valley and lower Great Lakes region. Aloft, the upper
level trough which allowed for our resurgence of autumn-like air
will be progressing east and retreating northward. Even as the
surface high departs eastward early in the week, it will continue
to ridge southwestward along the Appalachians. This will prevent
any significant low level moisture return, which should continue
to be the case through Saturday. Even though low level
temperature advection will be fairly neutral, a slow warming trend
can be expected as insolation works on the air mass.
A rather minor upper level trough is expected to pass over in the
Wed-Thu time frame. With very little moisture present, it
shouldn`t be strong enough to have any significant effect on our
weather. After this, model agreement starts to take a hit. The
latest deterministic GFS has a weak upper level trough dropping
southeast from the Great Lakes to the Mid Atlantic region in the
Fri-Sat time frame, with a notable increase in mid-upper level
moisture bringing virga. Even if this scenario came to be, it`s
still very questionable if the virga could overcome our dry lower
levels to eventually result in any precip. Meanwhile, the latest
ECMWF has transient ridging aloft building back in by Saturday.
Despite differing solutions, a model blend including ensembles
keeps the POP very low, and the forecast will remain dry.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 200 PM EDT SAT SEP 6 2025
A range of VFR to IFR conditions in light to briefly moderate rain
are noted across eastern Kentucky at the 18Z TAF issuance,
courtesy a slow-moving cold front. Rainfall will gradually
diminish from northwest to southeast between 19Z and ~0-3Z.
Temporary improvement in ceilings can be expected but widespread
post-frontal stratus and low fog is likely to form overnight with
widespread IFR or worse conditions developing. Winds will be
variable to northwesterly, generally around 5 kts or less.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...GEERTSON
LONG TERM...HAL
AVIATION...GEERTSON

NWS JKL Office Area Forecast Discussion