JKL issues Area Forecast Discussion (AFD) at Mar 4, 12:05 PM EST
904
FXUS63 KJKL 041705
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1205 PM EST Tue Mar 4 2025
.KEY MESSAGES...
- Windy late today into Wednesday.
- Dry and increasingly breezy conditions this afternoon into the
evening will result in near critical fire weather conditions.
- A period of showers will occur near and in advance of a cold
front tonight. Isolated thunderstorms are also possible.
- Additional showers should develop Wednesday, likely mixing with
or changing to snow for Wednesday night and Thursday morning,
with minor accumulations possible.
- Milder temperatures return to finish the week, along with a good
potential of more rain for most of the area.
&&
.UPDATE...
Issued at 1204 PM EST TUE MAR 4 2025
The forecast is being updated for the issuance of a Red Flag
Warning until early this evening.
UPDATE Issued at 943 AM EST TUE MAR 4 2025
Morning obs have been blended into the forecast with minimal
changes.
&&
.SHORT TERM...(Today through Wednesday)
Issued at 545 AM EST TUE MAR 4 2025
Early this morning, upper level ridging extended form the Gulf to
the Appalcahians and mid OH Valley to the Great Lakes while
another ridge was located from the eastern Pacific into the west
coast states. Meanwhile, troughing extended into portions of the
Rockies and Plains in between the two ridges from troughing over
eastern and central Canada. Within the troughing in the Central
Conus, an enlongated upper low was in place from NE to the TX
panhandle/western TX. At the surface, an occluded area of low
pressure was centered in KS to a triple point in OK and then a
cold front across the TX to the Rio Grande Valley. East of eastern
KY as ridge of high pressure was centered off the mid Atlantic
coast though its influence extended into the southeast and OH
Valley. Following the ridging that crossed the area over the past
couple of days, dewpoint locally area in the teens to mid 20s with
PW analyzed between 0.45 of an inch and 0.5 inches.
Through tonight, the upper level ridge axis will move further
east to and then eventually off the eastern seaboard through late
tonight. At the same time, the upper level ridge now along the
west coast of the Conus will move into the Great Basin and portion
of the Rockies area and approach the Four Corners region.
Meanwhile, the upper level low is forecast to reach the SE KS/NW
OK/SW KS to NW AR vicinity this evening and then trek into the mid
MS Valley and Lower OH Valley region and into IL by dawn on
Wednesday. A lead shortwave trough should near the TN and Lower OH
Valley later today and then work across the Commonwealth through
late tonight and early on Wednesday. Meanwhile, the sfc low should
reach MO by this evening and then IL tonight. The associated
occluded front is progged to move across the Commonwealth tonight
entering eastern KY not long after midnight while the triple point
passes just south and southeast of the Commonwealth. The upper
level low will meander toward MI on Wednesday while the trailing 500
mb trough moves east but lags west of eastern KY. The sfc low
should track into MI on Wednesday as well with the occluded front
moving further northeast of eastern KY while a secondary cold
front crosses the central and eastern parts of the Commonwealth.
For wind gusts, opted to go higher than NBM deterministic from
about 15Z today, or 10 AM EST through 00Z or 7 PM EST Wednesday,
blending in the 90th NBM percentile and a mix of higher
resolution model data from the ConsShort and the 06Z HRRR
considering the strength of the low pressure system. Winds are
expected to increase through the day and tonight as the pressure
gradient increases and winds aloft also increase. A dry airmass is
in place across the region as are dry fuels as very little rain
has fallen since February 20th. The southeast to south winds will
gradually lead to an increase in moisture/dewpoints from midday
and the afternoon onward. Guidance continues to support that
although many locations will fall to or be near critical humidity
levels late in the morning to early afternoon, winds reaching
critical fire weather criteria should not occur concurrently.
Thus, the threat for enhanced fire danger was highlighted in the
HWO as well as an SPS and in DSS packets and social media.
Outside of any convective line, per recent HRRR runs as well as
00Z HREF, the most likely locations to receive advisory or higher
gusts this afternoon and evening is the higher terrain on and just
downwind of Black and Pine Mountain in the Letcher and Harlan
County areas as well as areas from about I 75 westward. The 00Z
HREF has mean wind gusts to 60 mph in these areas. Even if this is
a bit overdone in areal extent, wind gusts to lower end warning
criteria are possible in both areas. Per coordination that
considering forecaster confidence, opted to hold off on any High
Wind Warnings from about I 75 west to the Lake Cumberland area at
this point, while hoisting one for Harlan and Letcher counties
from late this afternoon and into the overnight hours, with a Wind
Advisory to follow.
As for thunder chances, the 00Z LREF has mean MUCAPE of up to 100
J/kg briefly near the boundary and into the 100 to 150 J/kg range
into areas near the Lake Cumberland area. The most probably
scenario is that the area precipitation will likely largely or
entirely showers with strong gusts into the advisory range for
areas generally near or west of the escarpment and also near or
south of the Mountain Parkway. However, a few rumbles of thunder
cannot be completely ruled out if just a small amount of
instability is realized given the anticipated shear and if this
occurs, there would be an uptick in wind gusts to severe limits as
in portions of the potential convective line containing embedded
storms.
After the boundary passes, a general lull in wind gust magnitude
is anticipated for a few hours late tonight to a couple of hours
past dawn on Wednesday. However, once heating occurs on Wednesday
within an anticipated pronounced dry slot with the dynamic sfc
low and secondary boundary working in combined with cooling
aloft, momentum of stronger winds should begin to mix to the
surface again. Gusts into the 40 to 50 mph range or wind advisory
range area anticipated generally areawide. A wind advisory for
Eliott, Morgan, and Rowan counties may be needed for that
timeframe. Per the 00Z HREF mean, 850 mb temperatures should drop
from the 3 to 8C range at dawn Wednesday to the 0 to about -6C
range by early Wednesday evening. Deeper moisture will also
increase as it wraps back across the area and the upper level
trough axis nears. This should bring a return of rain with
embedded heavier areas of rain or showers of varying intensity
particularly for midday through the afternoon. The top of Black
Mountain will begin to cool, and precipitation there may mix with
or possibly change to snow by Wednesday evening.
Temperatures will remain above normal through tonight, though
after midday to early afternoon, cold advection will lead to
temperatures on Wednesday afternoon falling below normal for this
time of year.
.LONG TERM...(Wednesday night through Monday)
Issued at 425 AM EST TUE MAR 4 2025
The models, and their individual ensemble suites, are in
relatively good agreement aloft through the rest of the work week
before the differences amplify to the point of greater uncertainty
over the weekend. They are all onboard with a deep trough moving
through the Ohio Valley to state the long term portion of the
forecast. This trough will also have a significant extent of
itself pushing off the Georgia coast initially. The 5h trough
axis moves east of the area early Thursday morning followed by
local height rises and a period of northwest mid level flow. This,
rather fast, flow will carry more impulses through this part of
the state during the day Thursday before this energy stream moves
east by mid afternoon. Thursday night into Friday will see the
mid level flow flatten out to a more zonal pattern with west to
east streams of weaker energy passing overhead. Around this time,
the model suites start to diverge from each other concerning the
next deep shortwave diving through the Four Corners Region with
the GFS group faster in translating this system's core east than
those of the ECMWF. This has some downstream effects by Saturday -
centering around energy working through the state within still
nearly zonal mid level flow. The European version holds back the
bulk of this energy by 12 or so hours compared to the GFS and
leads to sfc development and impacts further south than
represented in the more evenly blended NBM. These differences
magnify by midday Sunday though about that time the bulk of any
energy is moving out of the region - to the east in the GFS runs
and holding to the southwest in the ECMWF ensembles. Regardless,
the upper pattern will become more settled with broad northwest
flow returning to Kentucky amid a burgeoning ridge, upstream, over
the Southwest on Monday. Ridging then gradually slides east
toward the region likely making for a quiet period of weather. The
model spread aloft being small supported using the NBM as the
starting point for the forecast grids up until the weekend when
more liberty was taken to favor the Euro blend. Did make some
adjustments to incorporate more terrain distinction in the
temperatures most of the drier nights of the long term portion of
the forecast.
Sensible weather features the diminishing effects of the major
late winter system passing through the Ohio Valley. Extensive wrap
around moisture and upslope flow on brisk northwest winds will
transition over to snow showers rather quickly after sunset
Wednesday from west to east. CAA cools the column with still some
lift around to loft the moisture into the colder air resulting in
a potential for accumulating snow into Thursday morning. Any
accumulations will be mitigated by wet ground/roads and antecedent
warm sfc temperatures. Still, do expect some brief accumulations
on grassy surfaces through the area that morning with up to an
inch possible in the highest terrain near the Virginia border. The
snow showers quickly taper to flurries and clear out by afternoon
from west to east. The northwest winds will slowly settle down by
Thursday evening but not before bringing in much colder air and
only a limited rebound in temperatures to the lower 40s - though
many locations will not get out of the 30s. This sets up a chilly
night into Friday morning with some terrain differences. Quick
moderation does follow, though, with temperatures back in the 50s
for Friday afternoon most places along with similar readings on
Saturday. The minor system that moves through to start the weekend
will only cool us off a tad into Sunday with highs limited to the
40s most places before milder conditions return for Monday and
we see real warmth on Tuesday. The biggest unknown remains that
Friday to Saturday system that the one cluster of solutions has
passing mostly north while the other favored cluster takes it
mainly south of the JKL CWA. Have played it cautious with fairly
small impacts and just moderate precipitation chances for now -
acknowledging that further refinements will be needed once the
models come into better agreement. The GFS also swings a sfc wave
south of the area to end the weekend brushing our southern
counties with some more pcpn chances - so there remains some
uncertainty to the actual starting time of our next stretch of dry
weather.
The changes to the NBM starting point consisted primarily of
adjusting temperatures for most of the dry nights. Did also lower
dewpoints in the afternoon for several of them through the long
term. As for PoPs, mainly lingered them in the east on Thursday
more than the NBM and also favored more of a southern construct to
the early weekend system.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 110 AM EST TUE MAR 4 2025
VFR conditions are forecast through at least 03Z in all areas,
with MVFR possible near Lake Cumberland late. Generally southeast
to south winds are expected through 15Z at 5 to 10KT or less with
gusts as high as 15KT. Thereafter, sustained winds will increase
to the 8 to 17KT range with gusts increasing into the 20 to 30KT
if not stronger by 21Z, especially near the TN border and
near/west of I-75. Some gusts may reach around 40KT near Lake
Cumberland at times during the last 9 hours of the period. Showers
should arrive near and west of I 75 late and isolated
thunderstorms will be possible. Outside of showers and any
thunderstorms, LLWS will be a threat.
&&
.FIRE WEATHER...
Issued at 1204 PM EST TUE MAR 4 2025
Strong sun/heating and its resultant mixing is giving a faster
increase in winds and lower RH than was earlier forecast. Red flag
conditions were reported at multiple sites already. Dew points
will climb from southwest to northeast with time today, and
eventually push RH above the 25% threshold, but winds will likely
remain gusty.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 7 PM EST this evening for KYZ044-050>052-
058>060-068-069-079-080-083>088-106-108-109-111>118.
Wind Advisory from 6 PM this evening to 7 PM EST Wednesday for
KYZ044-050-051-058>060-069-086-087-107>117-119-120.
Wind Advisory from 3 PM this afternoon to 7 PM EST Wednesday for
KYZ068-079-080-083>085.
High Wind Warning from 4 PM this afternoon to 4 AM EST Wednesday
for KYZ088-118.
Wind Advisory from 4 AM to 7 PM EST Wednesday for KYZ088-118.
&&
$$
UPDATE...HAL
SHORT TERM...JP
LONG TERM...GREIF
AVIATION...JP
FIRE WEATHER...HAL
Source: JKL issues Area Forecast Discussion (AFD) at Mar 4, 12:05 PM EST (https://mesonet.agron.iastate.edu/p.php?pid=202503041705-KJKL-FXUS63-AFDJKL)
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