JKL issues Area Forecast Discussion (AFD) at Jan 26, 7:27 AM EST823
FXUS63 KJKL 261227
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
727 AM EST Sun Jan 26 2025
.KEY MESSAGES...
- There is a chance for minor accumulations of snow Sunday night
across parts of eastern and southeastern Kentucky, particularly
south of KY-80 and the Hal Rogers Parkway.
- Temperatures should remain near if not a few degrees above
normal for most of the next week.
- A system will approach the area towards the end of the long term
forecast period, but confidence in timing remains low. Rain is
currently the favored precipitation type.
&&
.UPDATE...
Issued at 715 AM EST SUN JAN 26 2025
Hourly grids have been freshened up based on recent observations
and trends. Overall, this led to no substantial changes at this
time.
&&
.SHORT TERM...(Today through Monday)
Issued at 450 AM EST SUN JAN 26 2025
Early this morning, south of an upper low just north of Hudson By
a broad trough extending south across Ontario and Quebec into the
Great Lakes and Northeast Conus. A couple of shortwaves were
moving through this trough, one nearing the eastern Great Lakes,
another in the vicinity of the western Great Lakes with another
upstream from the Manitoba/Ontario border southwest to ND and
eastern MT and WY. Meanwhile a closed low was located over
northern CA with Ridging over the eastern Pacific and also from
the Caribbean into Central America. In between, west to west
southwest flow aloft extended from the Central and Southern Plains
to the Mid Atlantic to Southeast Conus. A more southern shortwave
was located from NM to portions of Mexico. At the surface, a
ridge of high pressure extended from the Southeast Conus off the
southeast US coast and into the Atlantic with another area of
ridging from BC to parts of the interior Northwest to Northern
Rockies to Central Plains. In between a cold front extended from
low pressure in Quebec across the eastern Great Lakes to Lower OH
Valley to portions of the Southern Plains/eastern TX and then
into the southwest Conus. Downstream of the shortwave trough
approaching the Southern Plains, a wave of low pressure has
developed along the boundary over eastern portions of TX. High
and at times mid level clouds have been crossing the Commonwealth
ahead of the boundary with varying degrees of mixiness and
decoupling across the complex terrain of eastern KY. In general,
more of the sheltered valleys near or south of the Mountain Pwky
and east of I 75 were decoupled with temperatures in the low to
mid 20s, while temperatures elsewhere were in the low to mid 30s.
The exception is the highest terrain above 3000 or 3500 feet that
was also in the 20s.
Today and tonight, west to west southwest flow is expected to
persist from the Central to Southern Plains and into the eastern
Conus. This should occur as the southern shortwave trough moves
across parts of the Southern Plains and then into parts of the
southeastern Conus tonight and mergers with the more northern
shortwave that is progged to rotate across parts of Ontario and
the western Great Lakes as well as Northern Plains and Upper MS
Valley and across the Central and eastern Great Lakes and into the
Northeast to Lower OH and Mid MS Valleys. As this occurs, the cold
front should continue to move east and into the eastern Great
Lakes to Upper OH Valley to northern and western KY by dawn and
then sag further south of the Commonwealth today to southern NC
and southeastern and southern middle Tn to southeast TX near
sunset and then further south and southeast tonight to upstate SC
and northern to central AL to southern LA as one more surface
waves track along it from southeast TX to AL.
On the northern periphery of this front and sfc wave in a warm
advection/ overrunning regime, moisture is expected to increase
across the TN Valley and parts of the southern Appalachians and
into portions of KY late today and into this evening and lingering
into the overnight hours. There remains some uncertainty with the
northern extent of the deeper moisture, but the overall guidance
trend has been for this to reach into at least the southernmost
tier of counties from Letcher to Wayne if not a bit further north
or generally near the KY 80 and Hal Rogers Parkway as its
northernmost extent. Some light precipitation, with the best
chance of measurable along or south of the KY 80 and Hal Rogers
Pkwy appears probable. Initially as saturation of the lower
levels occurs, all but the highest elevations would probably yield
just rain or perhaps some sprinkles or flurries further north
toward the Mtn Pkwy corridor. However, as the column is progged to
cool late in the evening into the early part of the overnight
hours, any remaining precipitation would change to snow. Following
widespread temperatures in the 40s for most areas today, any
accumulations would be largely limited to elevated or grassy
surfaces or on top of lingering areas of snow cover. QPF will be
limited and for any of these areas where some accumulations occurs
on surfaces, it should only amount to dusting to a half of an
inch at the most. The exception would be locations at 2500 feet
and above on top of Pine Mtn from Bell to Pike Co/VA line, in the
Log Mtns of Bell County and the Black Mountain area of Harlan
County as well as the Flatwoods area of Pike County where a half
inch to an inch is possible. For now have mentioned the
possibility of a minor accumulation in some of the more southern
locations in the HWO.
Otherwise, the 500 mb/shortwave axis will cross the remainder of
the OH Valley and the Appalachians on Monday with sfc high
pressure nosing into the Lower OH Valley/Commonwealth form the
Southern Plains to Lower MS Valley vicinity. This should result in
the column drying out areawide, with decreasing sky cover and any
flurries that may be lingering near the VA border around sunrise
also ending quickly.
After variable hourly temperatures during the pre dawn hours,
temperatures will warm to levels warmer than the past week for
highs today despite the passage of the cold front. In fact, highs
should average 2 to 3 degrees below normal for late January. Lows
tonight should range from colder readings further northwest to
more mild readings nearer to the VA border where more cloud cover
will be most persistent and where light precipitation may occur.
Similar highs are anticipated on Monday that near normal for this
time of year, but probably average 2 or 3 degrees below normal.
.LONG TERM...(After midnight Monday night through Saturday)
Issued at 648 AM EST Sun Jan 26 2025
The first half of the long term forecast period features a quieter
weather pattern than what we have experienced here in Eastern
Kentucky as of late. The second half, however, features a large,
dynamic storm system ejecting out of the Great Plains and into the
Greater Midwest. Forecast models continue to disagree on exactly
where this system will track, how it will evolve, and when exactly
it will depart from the region. These differences lead to
significant spread in the available forecast guidance regarding
Friday and Saturday's temperatures, precipitation chances, and cloud
coverage. While confidence in sensible weather specifics decreases
towards the end of the period, the general trend towards seasonably
mild temperatures this week gives credence to the idea that this
will primarily be a rain event.
Out ahead of this system, expect mostly dry weather. Persistent WNW
flow aloft will pump a continental airmass into the atmospheric
column from Monday night through Wednesday. At the surface, a broad
high to our south will yield SW winds, but with little to no
moisture advection. This means that any shortwave disturbances
traversing through the broad upper level longwave troughing over the
region will be moisture starved. Guidance resolves two of these
features: one late Monday night into Tuesday morning and another
Wednesday evening. The first may produce some mid/upper level
clouds, but will have little to no surface reflection. As a result,
expect efficient diurnal temperature curves and a warming trend.
Monday night, valleys will cool off into the mid 20s while ridgetops
remain closer to 30 degrees. Under mostly clear skies, Tuesday's
afternoon highs recover to the mid/upper 40s, with overnight lows
well above freezing in the upper 30s. The second disturbance on
Wednesday is marked by a weak surface trough, and it is forecast to
produce slightly more cloud cover as a result. The best upper level
dynamic support for Wednesday's system will remain displaced to the
north of the Ohio River, and the best lower level moisture will
remain further to the south in the Tennessee Valley. Thus, any
precipitation produced by this system would come from orographic
lifting processes in our southeastern terrain. The latest guidance
has backed off on this idea, but due to the signal in previous runs,
a few showers or sprinkles cannot be ruled out along the Virginia
border on Wednesday night. Thus, the greatest impacts from
Wednesday's weak disturbance will be the colder temperatures in its
wake. Afternoon highs in the 50s will drop to below freezing
overnight, but Thursday's temperatures recover into the mid/upper
40s under mostly clear skies.
By Thursday night, the surface high will have slid towards the
Carolinas, placing the forecast area in a regime of weak moisture
return. As the parent upper level low approaches on Friday and
Saturday, flow aloft shifts to a westerly and then a southwesterly
orientation. This shift will lead to efficient moisture return,
warming temperatures, and rain as the precipitation for most of the
event. A brief period of wintery precipitation cannot be entirely
ruled out if the system trends faster and precipitation begins early
on Friday morning. There is currently a 15 degree spread in the low
temperature forecast guidance for that timeframe, which exemplifies
the higher-than-usual uncertainty surrounding this event. Interested
parties are accordingly encouraged to monitor future forecast
packages for changes closely.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 727 AM EST SUN JAN 26 2025
A gradual increase as well as thickening and lowering of high and
some mid level clouds is anticipated today as a cold front sags
across eastern KY today and then settles south of the region. An
upper level disturbance and associated sfc low will move along the
boundary will track from TX to AL through the period. This will
lead to a lowering of clouds bases across the southern locations
generally after 18Z with the arrival of low clouds. VFR conditions
are forecast areawide through 21Z, but then MVFR should develop
across southern portions of the area. Accompanying the clouds
will likely be some light wintry precipitation that could also
reduce visibilities into the MVFR range during the 03Z to 10Z
timeframe with also potentially lowering ceilings to IFR or lower,
generally near or to the south of a KSME to KLOZ to KJKL to KSJS
line. Winds will initially be south southwest to west at 5 to 10KT
or less, but should become before become west in all areas through
18Z around 5 KT, and then average west to northwest around 5KT or
less through the end of the TAF period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...JP
LONG TERM...MARCUS
AVIATION...JP
Source:
JKL issues Area Forecast Discussion (AFD) at Jan 26, 7:27 AM EST---------------
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