JKL issues Area Forecast Discussion (AFD) at Jan 25, 6:00 AM EST018
FXUS63 KJKL 251100
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
600 AM EST Sat Jan 25 2025
.KEY MESSAGES...
- Temperatures moderate to normal levels today and then should remain
near if not a few degrees above normal for most of next week.
- A less active weather pattern is in store for next week.
&&
.SHORT TERM...(Today through Sunday)
Issued at 515 AM EST SAT JAN 25 2025
Early this morning, an upper level low was centered over the
Northeast Conus while an upper level low was centered north of
Hudson Bay with a rather broad upper level trough south across
Ontario and into the Northern Plains/western Great Lakes with
troughing also extending southwest across the Dakotas and MT to
CA. The upper flow between this scenario and an upper level ridge
centered in the Caribbean and extending west into Mexico was more
or less zonal westerly from the Central and Southern Rockies
across the Central Conus and into the OH Valley and eastern Conus.
At the surface, a ridge of high pressure extended from the Lower
MS Valley across the Southeast and into the OH Valley and Mid
Atlantic States to Quebec. Meanwhile a couple of weak low pressure
systems were upstream of the region. One centered in WI with a
warm front south to near the confluence of the OH and and MS
Rivers while a cold front south and southwest across parts of the
Plains and meandering into CA. Further north another sfc low was
centered just east of the Ontario and Manitoba border with a cold
front trailing into MN and the Dakotas to MT. Locally across
eastern KY skies have been mostly clear to clear with only some
passing cirrus at times. Temperatures have dropped off into the
mid to upper single digits for the more sheltered valley
locations, but were mainly in the teens and ranged to around the
20 degree mark in the coalfield ridges.
Today and tonight, the upper low initially over the Northeast is
expected to move east northeast and become an open wave int he
vicinity of the Maritimes. Meanwhile, a shortwave progresses across
the Great Lakes and into Quebec and the St Lawrence valleys while
the next one upstream tracks into ONtario and across the Upper MS
Valley to the western Great Lakes through this evening and across
the Central Great Lakes to the eastern Great Lakes tonight. During
this period, the next shortwave trough in northwest flow between
ridging in the Pacific and upper low and mean 500 trough in Canada
will arrive into western Ontario to the Northern Plains/Dakotas and
an upper level low is expected to close off over Northern to Central
California. A shortwave in west southwest flow to the south and
southeast of the CA upper low should eject into the Southern Plains
and trek to near the Arklatex to end the period while the more
northern shortwave progresses further across Ontario to the Central
Great Lakes to mid MS Valley region.
At the surface, the first weak low should track across the Lake
Superior vicinity and into Ontario today and weaken while the
trailing warm front lifts northeast across the Lower OH Valley and
into the eastern Great Lakes and Upper OH Valley. The cold front
associated with this system should also weaken and become rather
diffuse. The ridge of surface high pressure meanwhile will shift
south and southeast of eastern KY during this time with a modest
increase in the pressure gradient between the ridging and lower
pressure to the north and west of the area. Winds aloft will also
increase a bit this morning and int the afternoon and BUFKIT
momentum transfer for recent GFS and NAM runs suggests gusts to
around or approaching 20KT possible late this morning into the early
to mid afternoon timeframe. 00Z HREF mean wind gusts also suggest
similar if not slightly stronger magnitude gusts from the south to
southwest during that time. For the nocturnal mix-out timeframe into
the afternoon opted to go with wind gust above the NBM deterministic
and toward the higher percentiles of the NBM and more in line with
the higher resolution models such as the HRRR and HREF data. These
south to southwest winds will usher in milder air and
temperatures should peak near normal for this time of year.
The second sfc system associated with a shortwave trough to rotate
across parts of Ontario and the Great Lakes should move across
Ontario and the Lake Superior vicinity today and then into Ontario
tonight. The associated cold front should advance across the upper
MS Valley and into the western and central Great Lakes to the mid MS
Valley to the southern Plains through this evening. One or more
waves is anticipated to develop along southern end of the boundary
in the Red River of OK/TX vicinity and then track to southeastern TX
through Sunday. The northern portion of the boundary should track
across the central Great Lakes and into the eastern Great Lakes and
Lower OH Valley tonight as the sfc low moves into Ontario. As the
low in Canada moves into the Maritimes on Sunday, the cold front
should continue east and off the Northeast to mid Atlantic coast
though it should only sag a bit south of the Commonwealth and into
the Southern Appalachians to TN Valley by the end of the period.
Despite the approach the cold front tonight, the evening until
around midnight if not a couple of hours after should be devoid of
low and mid clouds and this should allow for sheltered valleys in
the southeast to decouple and drop off into at least the mid 20s
while lows further west and northwest and on ridge only fall to
around or just below the freezing mark. With the boundary and
associated cloud cover as well as the advection of a slightly cooler
airmass into the region, highs on Sunday should average about 2
degrees colder than today. During the near term period, the boundary
is not expected to produce any precipitation across the
Commonwealth, though some light precipitation may develop to the
southwest of the area in the TN Valley over western or middle TN
before the end of the period. Some of this very light precipitation
could skirt the TN and VA border region early in the long term
period.
.LONG TERM...(Sunday night through Friday)
Issued at 559 AM EST Sat Jan 25 2025
Confidence in next week's sensible weather forecast for Eastern
Kentucky has increased compared to this time yesterday. Over the
past 24 hours, the forecast guidance suite has come into notably
better agreement regarding the timing and amplitude of the synoptic
scale features that govern the long term forecast. This increasing
consensus is observable in the NBM 1D viewer box and whisker plots,
which show a significantly smaller spread between the 25th and 75th
forecast temperature percentiles through Thursday. While spread
increases to between 10 and 15 degrees for Thursday night and
beyond, this is largely an artifact of the previous day's
disagreement. If the trends/features observed in yesterday's 12z and
00z model runs continue into today's, confidence in future forecast
packages may be high enough to provide more specific details
regarding precipitation type and timing for a stronger storm system
approaching the area next weekend. This particular long term
forecast package, however, focuses more on the broader synoptic
scale trends.
The period opens on Sunday night with a weak cold frontal boundary
over southeastern portions of the forecast. Guidance continues to
trend drier with this system, although a few models, such as the
NAM, continue to resolve light amounts of precipitation near the
Tennessee and Virginia state line into Monday. Weak SW flow out
ahead of FROPA may yield just enough moisture advection to squeeze
out some light precipitation. The highest PoPs in this package
remain displaced to our South, but low-impact flurries were
introduced along and south of the KY-80/Hal Rogers Parkway corridor
to account for the wetter model solutions. Expect cloud coverage to
clear from north to south overnight into Monday morning, with low
temperatures corresponding to the amount of lingering clouds. North
of I-64, clear skies may allow temperatures to drop below 20
degrees. Further to the south, expect temperatures in the mid to
upper 20s.
Early next week, broad longwave troughing will extend from Canada
into the northeastern quadrant of the contiguous United States. Out
west, a closed upper level low will spin over Southwestern States.
This will position the Greater Ohio River Valley in a regime of
quasi-zonal, WNW flow. A post-frontal surface high pressure system
will foster clear skies and efficient diurnal temperature curves on
Monday and Tuesday. Expect afternoon highs to recover into the 40s
on Monday and then approach the 50s on Tuesday as surface flow turns
SW and intensifies. Monday night's lows will feature ridge-valley
temperature splits, with ridgetops near freezing and sheltered
valleys in the mid 20s.
On Wednesday, a shortwave disturbance will navigate through the
aforementioned upper level troughing. The surface reflection of this
disturbance is likely to take the form of a quick-moving clipper
system, and a cold front is accordingly poised to sweep across the
forecast area on Wednesday evening. Despite increasing cloud
coverage, persistent SW flow will allow highs between 50 and 55
degrees out ahead of this front. While models agree on this general
set up for Wednesday, they do not agree upon the magnitude of the
moisture return out ahead of it. PoPs are accordingly limited to
slight chances in the southeastern half of the forecast area on
Wednesday evening. There, the post frontal shift towards upslope
flow may provide just enough orographic lift to squeeze out some
light showers. Because FROPA is likely to align with the diurnal
temperature cycle, Wednesday nioght's temperatures will likely
quickly drop into the 30s and then the upper 20s. The potential for
a changeover from rain to snow will be monitored closely, but the
current timing of the system is more likely to yield rain. Snow may
fall atop Black and Pine Mountains on Wednesday night, but
significant accumulations and societal impacts look unlikely due to
the parent system's speed and the antecedent warmth.
The passage of Wednesday's shortwave disturbance will allow the
upper level pattern to become more progressive. Stubborn longwave
troughing will shift further and further to the NE on Thursday and
Friday, and the closed low over the desert SW will eject into the
Plains by next weekend. This will set the stage for a stronger storm
system to approach the region by next weekend, but the trend towards
a weekend time frame is not fully reflected in the NBM yet. As such,
the PoPs in the grids for Thursday night and Friday are likely an
artifact of older data, and the best precipitation chances in
Eastern KY will likely hold off until Saturday. It remains too early
to provide details regarding precipitation types with this system,
as it will likely depend on how the onset timing of said precip
onset aligns with the diurnal temperature cycle. The present of a
warm front out ahead of this system may further complicate things,
so interests are encouraged to stay tuned as the late-week sensible
weather forecast becomes further refined in the coming days.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 130 AM EST SAT JAN 25 2025
The TAF sites were under clear skies and VFR conditions at TAF
issuance with a ridge of high pressure extending from the Gulf
coast states into eastern KY. High clouds should traverse the
region during the TAF period with westerly flow aloft prevailing.
Light and variable winds will prevail overnight, with winds
picking up around 15Z into the 5 to 10KT range from the south to
southwest with gusts generally into the 15 to 20 KT range through
about 22Z before once again slackening.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JP
LONG TERM...MARCUS
AVIATION...JP
Source:
JKL issues Area Forecast Discussion (AFD) at Jan 25, 6:00 AM EST---------------
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