JKL issues Area Forecast Discussion (AFD) at Jan 21, 5:01 AM EST119
FXUS63 KJKL 211001
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
501 AM EST Tue Jan 21 2025
.KEY MESSAGES...
- Very minor snow accumulation possible this afternoon into this
evening for some locations near/north of US-421.
- Apparent temperatures (wind chills) fall to below zero for much
of the area late tonight into Wednesday morning.
- Temperatures gradually moderate back toward normal late this
week.
&&
.SHORT TERM...(Today through Wednesday)
Issued at 501 AM EST TUE JAN 21 2025
A frigid start to the day is ahead across eastern Kentucky as
temperatures generally range from 0 to 10 above (a touch warmer in
the far southeastern corner of the state and a bit cooler in the
more sheltered northern hollows). These values have actually
warmed a bit over the last several hours as mid-high clouds have
streamed in from the southwest ahead of an approaching cold front
and a full latitude 500H trough. The latest analysis shows the
aforementioned front extending from an ~1025 mb low over eastern
Lake Superior southward through Indianapolis, IN then
southwestward across the Mid-Mississippi Valley, through the
ArkLaTex and on into the Lone Star State. Looking aloft, a
positively-tilted full-latitude 500H trough lies behind the
surface front extends from an ~492 low over southern Baffin Island
southwestward to over the Baja California. An ~1043 arctic high
is centered over eastern Kansas.
The cold front will trek eastward today with clouds filling in and
lowering through the morning. Temperatures will also rebound
ahead of the boundary, into the upper teens north to as "warm" as
the mid 20s in the southernmost valleys. Model soundings show
limited shallow moisture in a steep low-level lapse rate
environment along and just behind the front. CAMs and the low-res
models suggest that some snow shower and flurry activity is
possible, as the front passes, primarily north of the US-421
corridor. Given the very cold temperatures QPF will be very
limited, but high SLRs in the 20 to 30:1+ range should support up
to a few tenths of snow accumulation at some locations.
Lingering flurries and low clouds will erode/dissipate from the
northwest this evening as the front departs and the 500H trough axis
passes overhead. In their wake, rising heights aloft will support
the arctic high shifting east and cresting over central and
northern Kentucky overnight. With light variable to calm winds,
clear skies (except perhaps a few lingering low clouds near the VA
border), and very dry air (PWATs ~0.05 inch or less), anticipate
strong radiative cooling to ensue after sunset. While most
southern valleys and ridgetops south of the Mountain Parkway are
likely to see lows on either side of 0, colder hollows
(especially toward Lake Cumberland and north of the Mountain
Parkway) could dip to between -5 and -10F in line with the 5th
percentile of the NBM. Any stirring of the wind will only
compound these frigid temperatures. Thus the Cold Weather Advisory
will remain in effect through tonight.
The arctic high will shift east of the area on on Wednesday
allowing a milder southerly flow to develop during the daylight
hours. This combined with mostly sunny skies will set the stage
for a noticeably milder afternoon with temperatures peaking in the
lower 20s north of I-64 up to the lower 30s in southern valleys.
.LONG TERM...(Wednesday through Monday)
Issued at 420 PM EST MON JAN 20 2025
Long wave troughing dominates across the central CONUS through
Thursday evening, before a transition to a split flow pattern
takes place this weekend and into early next week. Models have
remained in good agreement through the first half of the extended,
but then continue to be at odds with operational and ensemble
spread increasing quite a bit towards early next week.
The well below normal temperatures will roll on through Friday,
as the arctic air mass only gradually relents. As such, have
stayed closer to the 25th percentile for the daytime highs
Wednesday through Friday, which modify from the 20s on Wednesday,
to the lower and middle 30s on Friday. For overnight lows, have
maintained readings nearer or somewhat below the 5th percentile of
the blended guidance for valleys, given the lingering snowpack.
Single digits, with even a few particularly sheltered sites
getting down to near zero or slightly colder, will be possible
Thursday morning. These will modify to around 10 by Friday
morning, with an influx of clouds and a chance of very light
snow/flurries just before dawn Friday and continuing through the
day. This will occur in response to a passing upper level
disturbance. Time height shows fairly shallow moisture and weak
lift, so do not foresee anything impactful at this point.
More decisive return flow ensues this weekend and into early next
week, bringing readings back toward near normal temperatures
Saturday through Monday. Highs will rebound to the mainly the 40s,
while lows warm to the 20s and 30s. Better precipitation chances
will also move in Sunday and Monday; however, model spread
precludes going with likely PoPs just yet. Consequently,
precipitation-type details also remain low confidence, and will
await further model continuity before highlighting any meaningful
impacts.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 105 AM EST TUE JAN 21 2025
Skies were mostly clear at issuance with widespread VFR over the
area. An increase in high to mid-level clouds is expected through
the remainder of the night. Lower level moisture should begin to
arrive during the 12Z to 18Z period and bring a gradual decrease
in ceilings to the lower end of the VFR range. Some MVFR is
possible for northern and eastern sections by the 15Z to 19Z
timeframe, lingering into the evening hours. KSYM, KJKL, and KSJS
would be most likely to experience a few hours of MVFR during the
afternoon and early evening. Winds will be generally variable at
5KT or less through 13Z before increasing to 5 to 10KT with some
gusts into the 15 to 20KT range possible.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Cold Weather Advisory until 10 AM EST Wednesday for KYZ044-
050>052-058>060-068-069-079-080-083>088-104-106>120.
&&
$$
SHORT TERM...GEERTSON
LONG TERM...JKL
AVIATION...GEERTSON/JP
Source:
JKL issues Area Forecast Discussion (AFD) at Jan 21, 5:01 AM EST---------------
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