-- Discussion containing changed information from previous version are highlighted. --
828
FXUS63 KJKL 081743
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
143 PM EDT Tue Jul 8 2025

.KEY MESSAGES...

- High temperatures will return to near normal through the week as
  humidity increases.

- Chances for shower and storms persist through the upcoming
  weekend, mainly during each afternoon and evening.

&&

.UPDATE...
Issued at 1221 PM EDT TUE JUL 8 2025

Scattered convection, associated with the nearby cold front, has
developed in counties along and adjacent to the I-64 corridor.
Further south and east, SPC mesoanalysis indicates 1,000 to 1,500
J/kg of MLCAPE already south of I-64, with some additional
destabilization likely heading into the afternoon hours. CAMs
support shower/thunderstorm coverage increasing in extent as this
activity gradually sinks southeastward through the afternoon with
the most widespread coverage over the eastern half of the Jackson
CWA. EBWD nearing 20 kts is sufficient for multi-cell clusters.
It is also worth noting that the modeled sounding profile is
supportive of a low-end microburst threat further southeast, but
DCAPE is only marginally favorable for severe strength wind gusts.

UPDATE Issued at 815 AM EDT TUE JUL 8 2025

A cold frontal boundary lingers just off to our northwest at
update issuance (from roughly Wilmington, OH to Louisville, KY,
and then west through St. Louis, MO). Some weak convection is
ongoing near the boundary and a stray shower or thunderstorm
could drift into or popup over our northwestern counties through the
remainder of the morning, thus warranting a low PoP chance.
However, as the boundary seeps further southeast and into the JKL
CWA this afternoon, weak boundary convergence/differential heating
is expected to spark scattered thunderstorms (to locally numerous
in far eastern Kentucky) in a moderately unstable atmosphere.

UPDATE Issued at 1147 PM EDT MON JUL 7 2025

Made small changes to PoPs and Sky cover in addition to
initializing the temperature forecast with the latest
observations. There are no changes to the short-term forecast and
forecast reasoning.

UPDATE Issued at 834 PM EDT MON JUL 7 2025

Made a small update to PoPs through midday Tuesday.

Convection has developed this evening as a low-level jet has
developed, which seems to be well forecast by the GFS. The warm
advection associated with this low-level jet will likely keep at
least isolated showers and thunderstorms going across the
northwestern half of the forecast area through the overnight.
Nevertheless, can not completely rule out activity across any part
of the forecast area through Tuesday morning.

UPDATE Issued at 654 PM EDT MON JUL 7 2025

Increased PoPs to keep low-end (i.e., slight chance) in the grids
and text forecasts through tonight given an approaching front,
weak disturbance aloft, and continuing warm advection through the
overnight as indicated by forecast low-level wind increases just
above the surface inversion over eastern Kentucky. No other
significant changes were made with the early evening update.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 252 PM EDT MON JUL 7 2025

A pattern shift has occurred across the CONUS as the upper-level
ridge, which had brought warm and dry conditions, has broken down.
Surface high pressure still persists over the southeastern US;
however, a cold front is slowly tracking toward the CWA from the
northwest. Locally, showers and thunderstorms have already developed
ahead of this approaching boundary, and southwesterly flow continues
to advect warmer temperatures into eastern Kentucky. This
southwesterly flow has allowed temperatures to climb into the upper
80s, approaching the lower 90s.

A weak upper-level trough will pivot overhead through the CWA
tonight, but the primary forcing for the surface low responsible for
the cold front is situated over the Canadian Maritimes. Upper-level
forcing abandons the front, which is expected to stall along the
Ohio River later today. This will keep the CWA on the warm side of
the front, with highs climbing into the lower 90s. Additionally,
sufficient lift is in place to allow for the development of
widespread showers and thunderstorms. The severe thunderstorm threat
appears marginal due to weak effective bulk shear values; however,
there is upwards of 1,100 J/kg of DCAPE, leading to the potential
for gusty outflow winds. Showers and storms will taper off toward
sunset, leading to a dry overnight. Overnight lows will be in the
upper 60s to lower 70s, with areas of valley fog and fog developing
from todays rainfall.

Tuesday will feature similar weather to Monday, as the baroclinic
zone remains stationary, and the threat for strong storms develops
again Tuesday afternoon. Highs are forecast to climb into the upper
80s to lower 90s, with widespread convective activity expected.
Again, effective bulk shear values remain marginal, but DCAPE values
are high once more, and gusty outflows are expected. Showers and
storms will once again dissipate toward the late evening hours.
Expect another night with lows in the upper 60s and lower 70s,
accompanied by areas of fog.

Overall, an active forecast period is expected due to a stalled
frontal boundary. Afternoon convection is anticipated each day, with
highs in the upper 80s and low 90s. Each night will feature
overnight lows in the upper 60s and low 70s, along with areas of fog.

.LONG TERM...(Wednesday through Monday)
Issued at 400 PM EDT MON JUL 7 2025

The period is expected to begin with an upper level low over
Ontario and an associated trough south through the Great Lakes to
OH Valley to the Arklatex to western Gulf between an upper level
ridge centered near Bermuda and another upper level ridge centered
over the Southwest Conus. Guidance continues to have a shortwave
trough moving through the upper trough and across portions of the
OH Valley as the period begins while upper level trough should
extend from an upper level low in western Canada into the
Northwest Conus to CA. At the surface, a ridge of high pressure
is expected to extend from the Gulf of Mexico into the Southern
Appalachians with a frontal zone extending from off the Northeast
Coast to the mid Atlantic sates to a surface low in the Great
Lakes and then southwest and west to the mid MS Valley to Central
Plains. Another sfc system should be in advance of troughing in
western Canada and centered in Saskatchewan with a warm front
extending into the northern Plains and a cold front across
southwest Canada. Early on Wednesday, PW per the 12Z HREF mean is
forecast generally the 1.5 to 1.8 inch range a bit above normal
for this time of year nearer to the 75th percentile.

From Wednesday to Thursday night, the upper level low is expected
to move into Quebec with the northern portion of the trough
shifting into the Northeast to Mid Atlantic states through the
axis of troughing at 500 mb nears but generally remains west of
eastern KY. A couple of shortwave troughs are progged to cross
eastern KY during this time, one Wednesday to Wednesday evening
with another crossing the area about Thursday. As this occurs,
upper level ridging should remain centered in the western Atlantic
in the vicinity of Bermuda while upper level ridging remains from
the Southwest Conus/northern portions of Mexico into the eastern
Pacific. Meanwhile, upper trough should advance east toward
Central portions of Canada/Hudson Bay southwest to the Northern
Rockies crossing the Great Basin. Meanwhile, at the surface, as
the trough moves into eastern Canada and toward the Northeast, the
boundary north of eastern KY is expected to sag south of the
Great Lakes and extend from the mid Atlantic coast to OH to north
of the Ohio River to the next sfc system in the Plains. With the
trough axis near or west of eastern KY during this period,
convection cannot be ruled out at any point, with coverage likely
to peak each afternoon and evening. Valley fog should continue to
be a fixture each night to early morning and would be more
widespread or dense if clearing at night were to follow a period
of heavier rainfall. With the trough in place/come cooling aloft
cloud cover and precipitation should keep highs nearer if not
slightly below normal for this time of year.

Friday to Saturday night, some height rises are anticipated
across the Southeast for Friday into Saturday as an upper level
low organizes near the US/Canadian border near the
Ontario/Manitoba border to Northern Plains/Upper MS Valley areas
with troughing developing/moving into the Central Conus. During
this time, upper level ridging should remain in place across much
of the western Conus. At the surface, low pressure is expected to
trek from Manitoba toward the Hudson/James Bay region with the
trialing front advancing across parts of Ontario and into the
Central Great Lakes to mid MS valley to portions of the Plains. At
the same time, a sfc ridge of high pressure is expected to
generally remain from the Gulf into the Southeast/Southern
Appalachians. The region will remain in the warm sector with
convection possible through the period, generally each afternoon
and evening.

Sunday to Monday, upper level ridging is expected to remain from
the Southeast/Gulf of Mexico and across the Southwest Conus as the
upper low in Canada is progged to weaken and move toward Hudson
and James Bay. The shortwave trough to the south is generally
forecast to advance east across the Great Lakes and toward the
Northeast with run to run variability with timing and strength.
Another shortwave should also have moved across western Canada and
US/Canadian border. With the shortwave trough generally passing
north of the region, the surface low in Canada should move into
Quebec/eastern Canada with the trailing sfc front may become
diffuse with southern/southwest extent. Meanwhile, a ridge of sfc
high pressure should persist from the Gulf to the Southeast. With
no clear features to time for more organized convection at this
point, diurnal peaks in convection are anticipated to begin next
week as well. Temperatures per guidance should be near normal.

&&

.AVIATION...
-- Changed Discussion --
(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 143 PM EDT TUE JUL 8 2025

Scattered to locally numerous showers and thunderstorms are
anticipated this afternoon into this evening as a weak cold front
settles into Eastern Kentucky. This activity is covered by PROB30
groups, as it could easily lead to brief reductions in ceilings
and visibilities. Fog formation is probable in the typical valley
locales tonight and at terminals where shower activity lingers
late in the afternoon and/or evening (most likely at JKL and SJS).
Winds will generally be under 10 kts through the period, except
locally stronger and erratic near thunderstorms.
-- End Changed Discussion --

&&

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

&&

$$

UPDATE...GEERTSON
SHORT TERM...VORST
LONG TERM...JP
AVIATION...GEERTSON