JKL issues Area Forecast Discussion (AFD) at Mar 4, 5:16 PM EST197
FXUS63 KJKL 042216
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
516 PM EST Tue Mar 4 2025
.KEY MESSAGES...
- Windy late today into Wednesday.
- Critical to extreme fire weather conditions will occur through
this afternoon.
- 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
returning rain chances this weekend.
&&
.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...(Thursday through Tuesday)
Issued at 513 PM EST Tue Mar 4 2025
When the long term forecast period opens on Thursday morning, the
low pressure system responsible for the previous day's activity will
be ejecting off to the northeast. The cold air wrapping around the
backside of this low may combine with gusty WNW flow to produce a
few more hours of snow showers. In far eastern Kentucky, orographic
enhancements may yield light snow accumulations through midday, but
anything that falls is poised to melt off later that afternoon.
Upper level ridging and its associated surface high pressure quickly
build into the area in the wake of this low. Skies are expected to
correspondingly clear, and winds will steadily decrease throughout
the day as the pressure gradient expands. This will allow Thursday's
afternoon highs to recover into the 40s, which, in turn, mitigates
the potential for widespread travel impacts from the aforementioned
snow.
The upper level ridging flattens out on Friday, placing the forecast
area in a regime of quasi-zonal flow aloft. A weakening shortwave
disturbance and its associated surface low pressure system will
approach the region during this time frame, but the lack of well-
defined upper level support leads to relatively high levels of
forecast uncertainty. The various members of the guidance suite
continue to resolve a couple of distinct model solutions during the
Friday night-Saturday morning time frame. The northern group of
solutions tracks this low closer to the Ohio River, with stronger
southwesterly surface flow out ahead of an approaching frontal
boundary. This set of solutions is warmer, windier, and wetter,
whereas the southern group of solutions would keep temperatures
milder and precipitation lighter. The uncertainty continues into
Sunday, as a closed-upper level low ejects out of the Desert
Southwest. Guidance has collectively trended this feature towards a
southerly passage, but continues to resolve the timing and magnitude
of this feature quite differently. If the southerly trend continues,
the precipitation chances currently in the forecast for Sunday would
generally decrease. The 12z deterministic model runs portray this
downward trend, but the time-lagged NBM ensemble does not explicitly
account for that yet.
Due to the cumulative effects of this model uncertainty, this
particular forecast package does not deviate much from the NBM. As
of the time of issuance, Friday afternoon looks warmer and windier,
with increasing overnight rain chances and then a cooler and drier
Saturday afternoon. Light precipitation chances return on Sunday,
especially across our Southeastern Counties, and the cooler airmass
lingers through the end of the weekend. A quieter pattern and a
warming trend is poised to emerge by early next week. Mid-level
height rises signal the return of ridging, but the magnitude of this
feature will depend on the evolution of the weekend systems. Mostly
clear skies will favor efficient diurnal warming and overnight ridge-
valley temperature splits on Monday. Thus, highs are forecast to
progressively increase through the end of the long term forecast
period, and perhaps into the 70s beyond then. These sensible weather
details are likely to be refined as we work to analyze the latest
model data for trends and/or a consensus, so stay tuned.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1217 PM EST TUE MAR 4 2025
VFR conditions are forecast through at least 03Z in all areas,
with MVFR conditions are possible from west to east as a line of
showers and possible thunderstorms move east across the area
overnight into early Wednesday morning. The big story will be the
winds, which will remain quite gusty this afternoon out of the
south to southeast. Some locations may see surface winds diminish
for a time this evening, and where that occurs LLWS can be
expected. However, for the vast majority of locations wind gusts
will continue into the overnight. A brief period of somewhat
lighter winds will occur behind the line of showers and first
frontal passage late tonight into Wednesday morning before strong
southwesterly winds and wind gusts redevelop and continue through
the remainder of the TAF period. Some gusts may reach around 40KT,
especially within heavier showers late tonight, and developing by
midday Wednesday at the end the TAF period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 7 PM EST this evening for KYZ044-050>052-
058>060-106-108-109-111.
Wind Advisory until 7 PM EST Wednesday for KYZ044-050-051-
058>060-069-086-087-107>117-119-120.
Wind Advisory until 7 PM EST Wednesday for KYZ068-079-080-
083>085.
High Wind Warning until 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...MARCUS
AVIATION...CMC
Source:
JKL issues Area Forecast Discussion (AFD) at Mar 4, 5:16 PM EST---------------
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