JKL issues Area Forecast Discussion (AFD) at Apr 27, 12:09 PM EDT237
FXUS63 KJKL 271609
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1209 PM EDT Sun Apr 27 2025
.KEY MESSAGES...
- Near to slightly below normal temperatures are in store through
tonight, before above normal readings make a comeback for most
of the upcoming work week.
- There is a possibility of frost developing in sheltered rural
valleys and low-lying areas late tonight and early Monday
morning.
- The next significant potential for showers and thunderstorms
arrives Tuesday and continues at times through Friday. Some
storms, especially on Tuesday and Thursday, could be on the
strong side.
&&
.UPDATE...
Issued at 1209 PM EDT SUN APR 27 2025
Midday update is out with little in the way of significant
changes. Did reduce the Sky cover utilizing the CONSRAW model
as the NBM appears too pessimistic on cloud cover, especially in
the northeastern half of the forecast area.
UPDATE Issued at 750 AM EDT SUN APR 27 2025
Any traces of fog in valleys are rapidly diminishing as the sun
rises and drier air filters in from the northeast. Upstream dew
points are in the mid 30s over much of West Virginia. RAP/HRRR
guidance is supportive of dew points falling to near or below 32F
this afternoon across much of eastern Kentucky. If this
materializes and tonight's cloud cover remains relatively minimal,
frost headlines may be needed for northeastern portions of the
forecast area.
&&
.SHORT TERM...(Today through Monday)
Issued at 505 AM EDT SUN APR 27 2025
Temperatures are 10 to 15+ degrees colder this morning than
yesterday morning at this time. A chilly air mass continues to
infiltrate from the north. Temperature readings range from around
40F in the colder northern valleys to near 50F in the warmest broad
valleys of the Upper Cumberland Basin. A thin high cloud layer is
present over the Eastern Kentucky Coalfield and adjacent areas
while patchy fog has developed in some of the river valleys. The
latest surface analysis shows eastern Kentucky under the influence
of a high pressure system centered over Lake Michigan. The parent
500 H ridge extends from east Texas north northeast into Northern
Ontario. Meanwhile, an ~550 dam low is found upstream over Nevada.
That low will gradually to drift northeast over the next 24 to 36
hours while additional energy continues to dive into the western
side of the parent trough and increasing its amplitude. A
compensating rise in heights will occur within the downstream
ridge to our west through tonight. At the surface, high pressure
will keep a solid grip on our weather today and Monday as the
systems's center of clockwise circulation dives southeast to over
the Central Appalachians tonight and then off the Mid-Atlantic
Seaboard on Monday. This will keep our weather fairly quiet
in the short-term, though initially cool. A very weak disturbance
passing through the ridge aloft and a subtle lee side surface
trough over the western foothills of the Central Appalachians
might trigger an isolated shower on Monday afternoon; but, that
threat is low and mainly confined to locations near and southwest
of US-421. Some of the deterministic model soundings would suggest
instability is deep enough for a rumble of thunder, if convection
occurs.
In sensible terms, look for any fog to dissipate after sunrise.
Temperatures will rebound into the mid 60s north of the Mountain
Parkway and upper 60s to lower 70s further south by mid-afternoon.
A few of the warmest spots in the upper Cumberland River basin
(such as Middlesboro) could flirt with the middle 70s. Meanwhile,
dew points are expected to fall back into the 30s amidst deep
mixing and a drying northeasterly low-level flow. High cloud
cover will stream across the area throughout the day though
thickening and lowering somewhat over the southwestern third to
half of the forecast area in response to mid-level warm air
advection. For this evening and tonight, the combination of light
winds, mostly clear skies, and dry air will set the stage for
temperatures to drop sharply, especially in sheltered valleys over
our northeastern counties along and north of the Mountain Parkway
and east of the Pottsville Escarpment. In these areas, mid to
upper 30s temperature readings are expected to be common by Monday
morning with some of the coldest hollows approaching 32F. This
will be cold enough for areas of frost in some locales. Further
southwest, more cloud cover (though likely thin at times) should
help to slow temperature falls and keep frost more patchy and
limited to low-lying areas and the most sheltered of valleys. No
frost is expected southwest of US-25. Minimum temperatures on
ridges should largely stay in the 40s. Looking ahead to Monday,
temperatures will turn sharply warmer with thermometers surging
into the mid 70s to near 80 for most places during the afternoon
under mostly sunny skies. There is a low probability (under 20
percent) for a shower or thunderstorm in the afternoon, mainly
southwest of US-421.
.LONG TERM...(Monday night through Saturday)
Issued at 418 AM EDT SUN APR 27 2025
The forecast period begins with the area under the warm sector
behind an exiting warm front. Dry weather, within the warm sector,
will gradually diminish as the parent surface low tracks into
southern Canada and the associated cold front approaches the CWA
from the northwest. Increasing shower and thunderstorm chances are
expected Tuesday morning with a severe weather threat working into
the region Tuesday afternoon. The SPC has the area along and north
of the I-64 corridor under a Day 3 Slight Risk for severe weather.
Forecast deterministic soundings ahead of the boundary, on Tuesday
afternoon, have over 1,500 J/kg of SBCAPE and MUCAPE, over 1,000
J/kg of MLCAPE and both mid and low-level lapse rates approaching
7.0 C/km; however, the limiting factor is the 0-3 km bulk shear
which is forecast to be less then 30 kts. Nonetheless, there's
enough lift with the front and indices are mostly favorable for
the potential for damaging winds with the strong storms Tuesday
afternoon.
As the upper-level trough pivots to the northeast into the Canadian
Maritimes, the surface cold front is forecast to become an east-west
oriented stationary baroclinic zone where shower and storm
chances will exist through Wednesday evening. However, to the
southwest, an upper-level shortwave is expected to move out of
northern Mexico/southern Texas with an accompanying surface low.
The area of baroclinicity will transform into a warm front and
lift north through the area late Wednesday night early Thursday
morning. As the parent surface low and cold front approach the
area for Thursday afternoon, increasing shower and storm threats
will exist. There is some spread in the deterministic long-term
models with respect to the ability to recover Thursday afternoon.
The GFS is aggressive with recovery leading to a better threat
for severe storms but the ECMWF is pessimistic on the recovery
possibility and limiting the severe weather threat. Nonetheless,
Thursday should be monitored as a second potential severe weather
day in the forecast period. As the system slowly ejects off the
the northeast through the day Friday, surface high pressure will
build into the region leading to a relatively cooler and drier
weekend.
Overall, the forecast period is expected to be a rather wet and
stormy period. Temperatures are forecast to range from the mid-70s
to mid-80s with overnight lows ranging from the upper-40s to low-
60s. A relative cool-down is expected for next weekend behind a
departing cold front.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 735 AM EDT SUN APR 27 2025
VFR conditions at TAF issuance are expected to prevail through the
period. Any leftover patchy fog in valleys will dissipate quickly
after sunrise. Fog is forecast to develop in the deeper river
valleys once more tonight but is not expected to impact the TAF
sites. Otherwise, high and mid-level clouds will stream across
the region. Winds will be relatively light from the northeast to
east at between 5 and 10 kts today before slackening to light and
variable tonight.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...CMC
SHORT TERM...GEERTSON
LONG TERM...VORST
AVIATION...GEERTSON
Source:
JKL issues Area Forecast Discussion (AFD) at Apr 27, 12:09 PM EDT---------------
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