LMK issues Area Forecast Discussion (AFD) at Dec 1, 6:23 PM EST ...Updated Aviation Discussion...
916
FXUS63 KLMK 012323
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
623 PM EST Sun Dec 1 2024
...Updated Aviation Discussion...
.KEY MESSAGES...
* Scattered light snow and flurries are possible Monday, mainly in
the afternoon and evening. A dusting to as much as a half inch of
snow is possible, with the greatest chance of accumulating snow
across south central Kentucky.
* Very cold mornings early this week with lows in the teens to 20s.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 353 PM EST Sun Dec 1 2024
This Afternoon and Tonight...A mix of sun and clouds is observed on
latest satellite imagery across southern IN and central KY, with the
swath of accumulating snow from last night and this morning rapidly
shrinking over the past several hours. Where there has been more
sunshine, temperatures have jumped into the upper 30s and lower 40s,
with areas under more cloud cover remaining in the low-to-mid 30s.
The mid-level disturbance associated with the snow event last night
is now ejecting off the Carolina coast, with deep NW flow pattern
set up over the Mississippi and Ohio Valleys. This NW flow pattern
will promote continued cold advection through the evening into
tonight, bringing the coolest part of the arctic air mass into the
region for Monday into Tuesday.
The main question for the temperature forecast tonight surrounds how
much we can radiate out as waves of low- and mid-level clouds swing
across the region. Sfc high pressure ridging working in from the
northwest will allow winds to settle overnight, with winds remaining
light into Monday morning. Since most of the snow has melted across
the area, would not expect enhanced cooling due to snow cover. As a
result, will advertise mid-to-upper teens for lows tonight across
most of the area, with lows around 20 across south central KY and in
the Louisville Metro. Just before sunrise Monday, additional mid-
level clouds are expected to approach the region from the NW ahead
of the next system.
Monday...A mid-level shortwave and associated vorticity max
currently located over southern Manitoba and the upper Midwest will
descend within the NW flow regime tonight into tomorrow morning. By
late morning tomorrow, mid-level vort max is progged over central
IL, with differential CVA and broad rising motion moving over the
area late Monday morning through the afternoon hours. Model time-
height displays show an area of mid-level moisture moving into the
region tomorrow morning, with moisture building downwards through
the day. Overall, the moisture with this system is fairly paltry,
and though there is generally good dynamic support for precipitation
tomorrow, PW values between 0.3-0.4 should be the main limiting
factor for precipitation development. Light radar returns should be
evident by the mid-late morning hours, though initially sub-
saturated low levels should keep most precipitation from reaching
the ground until the late morning and afternoon hours. Hi-res model
consensus paints a swath of light QPF generally along and southwest
of a line from Jasper to Louisville to Richmond tomorrow afternoon.
Would expect a broad swath of flurries and light snow showers across
much of the area tomorrow afternoon, with light accumulations of a
dusting to as much as a half inch across the SW half of the forecast
area. With mostly cloudy to overcast skies expected during the day
tomorrow, temperatures will struggle to warm from lows this morning,
and the current forecast calls for highs in the upper 20s and low-t-
mid 30s.
&&
.LONG TERM /MONDAY THROUGH SUNDAY/...
Issued at 353 PM EST Sun Dec 1 2024
Monday Night - Tuesday Night...
Shortwave trough axis will be quickly pushing through the area late
Monday evening, with lingering flurries or light snow showers ending
across our SE CWA likely be Midnight. The bigger story will be the
cold temperatures as strong Canadian high pressure and dry NW flow
aloft dominate the region. Expect lows to be dipping well into the
teens by sunrise Tuesday under increasingly good radiational cooling
conditions. We do see plenty of sunshine on Tuesday during the day,
but given the cold start to the day we only struggle into the low
and mid 30s for highs. Dry and cold conditions continue on Tuesday
night, although a return of light southerly flow will actually help
temps rise a bit toward dawn. Still lows in the teens and low 20s
seem pretty reasonable before the slight recovery. Make sure the
kiddos are bundled up for the bus stop early this week!
Wednesday - Wednesday Night...
A strong shortwave trough will dig through the Great Lakes region on
Wednesday, dragging a mostly dry cold front into and through the
area. We will likely see some light showers or lingering drizzle
develop east of I-65 later Wednesday as the front passes through and
perhaps some upslope kicks in with the veering winds. Temps likely
allow for liquid initially, be Wednesday night precipitation could
end as some frozen precip, especially toward the I-75 corridor. We
do get a slight warm advection component ahead of this front, so
highs should be able to get back into the 40s which will be a
welcome change. Despite the milder temps, winds will be pretty gusty
in the 20 to 25 mph range, so 40s may still not feel all that mild.
In fact, the wind chill will still mostly be in the 30s with those
temps and winds combined.
Thursday - Sunday...
Another reinforcing shot of cold air arrives behind the departing
Wednesday cold front, with another strong Canadian high beneath
mostly dry NW flow aloft. This brings cold and dry conditions to end
the work week. Look for highs in the 30s each day, with lows in the
teens each night. Depending on when the surface high centers over
us, of the late week mornings could feature some single digit lows
in the cooler decoupled valleys. Something to watch.
The weekend is much lower confidence, although it looks to be me
mostly dry at the moment. Could have a weak shortwave/clipper system
diving through the NW flow aloft but plenty of time to work out
those details. The bigger focus will be on a potential developing
storm system somewhere in the region to start the new work week.
This is a bit outside the range of the current forecast, but right a
decent signal for some type of storm system early that next work
week.
&&
.AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 623 PM EST Sun Dec 1 2024
VFR conditions are expected through the upcoming TAF Period. Earlier
MVFR cigs have lifted and we had some temporary clearing. However,
another round of mid-level clouds are dropping into the region from
the northwest and cigs should settle down around 5kft AGL for this
evening and into the overnight period. Winds will remain out of the
NW at 3-8kts. Look for winds to back to the W/WSW on Monday with
cigs lowering through the day. Another clipper system will take aim
at western/central KY leading to some light snow toward the end of
the TAF period at the terminals.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
SHORT TERM...CSG
LONG TERM....BJS
AVIATION.....MJ
Source: LMK issues Area Forecast Discussion (AFD) at Dec 1, 6:23 PM EST ...Updated Aviation Discussion... (https://mesonet.agron.iastate.edu/p.php?pid=202412012323-KLMK-FXUS63-AFDLMK)
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