495
FXUS63 KJKL 182025
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
425 PM EDT Fri Apr 18 2025

.KEY MESSAGES...

- Above normal temperatures are expected for the next week.

- The next substantive chance at rain arrives Monday.

&&

.UPDATE...
Issued at 1040 AM EDT FRI APR 18 2025

Blended morning obs into the forecast without any meaningful
changes.

UPDATE Issued at 730 AM EDT FRI APR 18 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.

&&

.SHORT TERM...(Today through Saturday)
Issued at 445 AM EDT FRI APR 18 2025

08Z sfc analysis shows high pressure east of Kentucky with a
tightening gradient of pressure on account of deep low pressure
working towards the Mississippi River from the Great Plains. This
has lead to increasing winds aloft but a decoupled boundary layer
for most through eastern Kentucky this night - yielding a decent
ridge to valley temperature difference. Specifically, readings
range from the upper 50s and low 60s on the hills and the more
open areas of the west to the low and mid 40s in the sheltered low
spots of the east. Meanwhile, under mostly clear skies, dewpoints
are mainly in the mid and upper 30s. This has made for poor
moisture recovery - outside of the valleys.

The models, and their individual ensemble suites, are holding in
good agreement aloft through the short term period. They all
depict eastern Kentucky caught up in a tussle between strong, but
compact, ridging over the Southeast and deep troughing extending
from the Desert Southwest, though the Plains, and up to the
Great Lakes. The energy and mid level southwest flow associated
with the extensive troughing will be kept to the northwest of
this part of the state on account of the burgeoning Southeast
ridge for the near term. By Saturday, though, the swath of energy
does dip south toward northern parts of the JKL CWA for a time as
a couple of strung out waves move past in that increasingly deep
layer southwest flow. The still small model spread supported using
the NBM as the starting point with minimal adjustments needed
through the period - mainly to include more of a terrain
distinction to the temperatures this morning and again tonight
along with slightly drier afternoon RH today and Saturday.

Sensible weather features very warm conditions into the start
of the weekend as breezy south to southwest winds kick in today
owing mainly to the fairly tight pressure gradient ahead of a
stalled frontal boundary to the northwest. Enough dry air in place
for the area and the increasing winds will make for a dicey
situation for fire weather concerns despite the continued robust
greenup well underway. Have gone ahead and issued a fire danger
statement (SPS) into the first part of the evening for this
situation as RH will bottom out near 25 percent with wind gusts as
high as 30 mph for a time. For tonight, another ridge to valley
temperature split can be expected with overall milder conditions.
For Saturday, the support aloft in the north may allow for a
period or two of showers and stray afternoon thunderstorms
sneaking into the area from the wavering of the nearby stalled
boundary. Outside of the areas with more clouds and rain chances
to the north, temperatures will be even warmer - likely reaching
the mid 80s.

The changes to the NBM starting point primarily consisted of
adding more terrain distinction to the temperatures this morning
and again tonight as well as nudging down the dewpoints/RH each
afternoon though Saturday. As for PoPs - added some details from
the CAMs for Saturday allowing for better chances in the far north
than depicted by the NBM guidance.

.LONG TERM...(Sunday through Friday)
Issued at 425 PM EDT FRI APR 18 2025

The long-term period opens Sunday morning with an ~592 dam high
centered just off the Southeast US Coast and a negatively-tilting
500H trough extending from the Upper Missouri River Valley down
into the Southern Plains. At the surface, low pressure will be
organizing near/over Oklahoma, just to the east of the trough
axis. A cold front trails south from the low into the Rio Grande
Valley while another boundary stretches east and north of the low
through Mid-Mississippi/Lower Ohio Valleys and on across the
Central Appalachians (most likely just north of the JKL CWA).

The surface low will continue to organize and strengthen Sunday and
Sunday night as it lifts northeast toward Wisconsin. The boundary
initially lingering over the Ohio Valley and Central Appalachians
will lift back to the north as a seasonable surge of moisture
spreads across the Eastern Kentucky Coalfields on an intensifying
warm conveyor belt jet. Guidance does show sufficient instability
on Sunday afternoon for deep convection, but the potential for
capping keeps forecaster confidence low. Generally have included
at least a slight chance of a shower or thunderstorm on Sunday
afternoon/evening north of the KY-80/Hal Rogers Parkway corridor.
The best opportunity for some rainfall on Sunday, albeit still low
chance, is across the Bluegrass where weak pulses of energy will
be passing around the northwestern side of the 500H southeastern
high. It will be another warm day with thermometers climbing into
the upper 70s to near 80 over the Bluegrass and into the lower to
middle 80s elsewhere under partial sunshine. Expect the risk of
any shower or thunderstorm to diminish after sunset with the loss
of diurnally-induced instability. Most, if not all, of Sunday
night should be dry but mild with expected low temperatures in the
lower to middle 60s.

As the aforementioned surface low traverses the Great Lakes on
Monday, it will pull its trailing cold front into eastern
Kentucky. Instability does appear meager, likely due to increasing
cloud cover and the arrival of precipitation early in the day
before there is opportunity for strong heating. Expect high
temperatures in the 70s for many locations on Monday, though, if
sunshine persists long enough, some locations in far eastern
Kentucky could eclipse the 80 degree mark. By Monday night the
surface low and its parent trough will be lifting toward Quebec,
leaving the cold front with little forcing. As a result, expect
the cold front to stall south and east of Kentucky on Tuesday and
Wednesday. The deterministic 12z GFS more readily breaks down the
southeastern 500H ridge and pushes the front well beyond our
forecast area. The deterministic ECMWF/Canadian and a substantial
number of ensemble members are not so quick to push the front
through and in fact show at least some isolated to scattered light
precipitation lingering over southeastern Kentucky on both days,
especially during the afternoon and early evening, coincident
with peak diurnal heating. Tuesday should be seasonable with
afternoon maximum temperatures ranging in the 70s after morning
lows in the 50s. The coldest temperatures of the period are
forecast for Tuesday night when upper 40s to lower 50s could be
more common, especially in the more sheltered valleys. The air
mass modifies on Wednesday with more locations closing in or just
breaking past the 80F mark during the afternoon.

Better rain chances return for later in the week as the
baroclinic zone to our south drifts north and becomes a favored
corridor for a least a couple of waves of low pressure from
Thursday on into the last weekend of April. This will likely
translate into periods of unsettled weather at times with both
showers and thunderstorms possible, though the specifics remain
hazy this far out. Temperatures are expected to run well above
normal, with the mercury not far from 80F on both Thursday and
Friday afternoons.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 111 PM EDT FRI APR 18 2025

VFR conditions will prevail through the period. The primary
concerns will be wind. Gusts around 30 kts are occurring from the
south to southwest this afternoon, but will begin to subside
toward sunset. However, low level wind shear will then become a
concern through the night as southwest winds just off the surface
pick up to 40-50 kts. The wind shear will ease after
heating/mixing commences on Saturday morning.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 8 PM EDT this evening for KYZ052-058>060-
068-069-079-080-083>088-104-106>120.

&&

$$

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