JKL issues Area Forecast Discussion (AFD) at Jan 12, 12:06 PM EST
343
FXUS63 KJKL 121706 AAB
AFDJKL
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1206 PM EST Sun Jan 12 2025
.KEY MESSAGES...
- Patchy freezing drizzle will be possible Monday morning.
- Below normal temperatures will persist through Friday.
- Apparent temperatures could fall to near or below zero for many
locations Monday, Tuesday, and Wednesday nights - primarily
north of the Mountain Parkway.
&&
.UPDATE...
Issued at 1155 AM EST SUN JAN 12 2025
Hourly grids have been freshened up based on recent observations
and trends. This led to no substantial changes at this time.
UPDATE Issued at 735 AM EST SUN JAN 12 2025
Touched up the grids with a bit of fog in the southwest valleys
and to shrink the remaining clouds in the north with a few
lingering flurries. Did also add in the latest obs and trends for
the T/Td grids. These minor adjustments have been sent to the NDFD
and web servers.
&&
.SHORT TERM...(Today through Monday)
Issued at 500 AM EST SUN JAN 12 2025
09Z sfc analysis shows high pressure over the area with the next
area of low pressure to affect the state still back - well to the
northwest. This high has managed to partially clear the skies
through eastern Kentucky leaving some thicker and low clouds over
western parts of the JKL CWA but with a tendency to drift north
northeast through the night. The lack of clouds helped to
encourage radiational cooling which has driven the temperatures in
the cloudless valleys into the single digits. Specifically,
readings currently range from near 5 above in some of those
eastern sheltered valleys to the mid 20s under the lingering
clouds in the west. Meanwhile, amid light winds, dewpoints range
from the mid 20s under the clouds to the low dingle digits in the
far east. Cannot rule out some flurry activity beneath the clouds
early this morning along with patchy fog in the clear areas.
The models, and their individual ensemble suites, remain in
excellent agreement aloft through the short term portion of the
forecast. They all depict weak ridging flattening overhead in
response to a large area of troughing centered north of Minnesota
and extending south through the Central Plains. This trough will
slowly sink south into the States through Monday. As it does so.,
it allows the mid level flow over Kentucky to tighten and speed
up while holding generally from the west southwest. Weak energy,
initially, will push over eastern Kentucky today and tonight in
the mid level flow ahead of the trough before a more impactful
wave passes overhead Monday morning along with some slight height
falls. The still small model spread aloft continued to support
using the NBM as the starting point for the forecast grids, with
some adjustment per the latest CAMs for PoPs on Monday.
Sensible weather features the warmest day, today, of the next
several days with most places seeing highs in the upper 30s and
lower 40s along with plenty of sunshine. This will be one of the
best opportunities to dig out from the leftover ice and snow of
the past week. An approaching cold front then brings in more
clouds tonight and will help keep temperatures milder than most
are currently seeing. This front will also have enough support and
low level moisture for some very light pcpn. The problem with
this is that the best moisture does not extend high enough into
the colder air aloft to generate ice crystals for light snow or
flurries - especially lacking a seeder feeder mechanism from
above. For this reason, have introduced some freezing drizzle
into the forecast for Monday morning which could create a light
glaze on mainly elevated surfaces. In the wake of the front, by
afternoon, colder air aloft should be enough to end the light
pcpn as some flurries. Highs on Monday will be capped in the mid
to upper 30s with the afternoon CAA kicking in.
The changes to the NBM starting point consisted primarily of
tweaking the PoPs per the latest CAMs guidance. Did not deviate
too far from the NBM temperatures through the period - though did
continue to include a terrain enhancement for this morning's
readings where the skies are clear.
.LONG TERM...(Monday night through Saturday)
Issued at 359 AM EST SUN JAN 12 2025
Surface high pressure will build back into the region behind an
exiting cold front for Monday evening. However, upper-level height
falls, ahead of an approaching shortwave, will begin to work their
way into the forecast area. As the upper-level trough pivots
southeast into the region, an accompanying surface low will move
southeast with it. The clipper system will move through the region
bringing increased PoP chances (10-30%) for Tuesday night into
Wednesday morning. Did deviate from the NBM and decided to go with
the more robust GFS solution that provided better PoP chances across
the northern portions of the CWA; however, little to no accumulation
is expected with this clipper. Behind the exiting clipper, surface
high pressure will build into the region but CAA will bring some of
the coldest temperatures of the season to eastern Kentucky. Highs
Tuesday and Wednesday are forecast to climb into the low to mid-20s
with overnight lows Tuesday, Wednesday and Thursday mornings will
fall into the negatives to single digits. Another weak trough and
vort max will move through the area overnight Wednesday into
Thursday morning. This will provide enough lift to kick off a few
snow showers (0-30%) for areas mainly along and north of the
Mountain Parkway. Little to no accumulation is expected with this
second round of snow showers that'll linger into late Thursday night.
Models continue to show disagreement for Friday through the end of
the forecast period. The GFS is more robust in potential scenario
where a surface low develops over the southern Plains and ejects
toward the Great Lakes by Friday night. The ECMWF has a surface low
developing over the Gulf and track straight north and come in line
with the GFS solution. With confidence lacking in long-term
deterministic solutions, opted to stick with the NBM solution that
brings PoP into the region Friday afternoon and continues through
the end of the forecast period. Temperatures with this system are
forecast to run well above freezing which would lead to a rainy
solution. However, colder air will filter in behind the exiting
system which will turn rain into snow for all lingering backside
precipitation.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1206 PM EST SUN JAN 12 2025
Under the influence of sfc and upper level high pressure, VFR was
present across the region at this time. VFR conditions should
persist until 03Z in all areas before some MVFR ceilings are
likely to spread from northwest to southeast through the 11Z to
12Z timeframe in advance as well as behind a cold front. By 09Z to
12Z, further deterioration to IFR is anticipated over the western
and northwestern locations behind the boundary with the IFR
conditions possibly reaching KSYM and KSME by 12Z. The area of
IFR behind the boundary should shift across the eastern and
southeastern sections through the end of the period, while a
return to MVFR may arrive over the west and northwest late. Winds
are expected to south to southwest at generally 5 to 10 KT before
00Z and then become light and variable for valleys overnight
while ridgetop and more open terrain locations south to southwest
at 5 to 10KT. A shift to the west should occur behind the boundary
between 10Z and 18Z. There is some potential for spotty marginal
LLWS between 03Z and 10Z as the NBM suggests, but CONSShort is
more optimistic that it will not occur. With low confidence in
any LLWS occurrence, it will be left out of the 18Z TAF issuance.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...VORST
AVIATION...JP
Source: JKL issues Area Forecast Discussion (AFD) at Jan 12, 12:06 PM EST (https://mesonet.agron.iastate.edu/p.php?pid=202501121706-KJKL-FXUS63-AFDJKL-AAB)
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