LMK issues Area Forecast Discussion (AFD) at Jan 1, 3:17 AM EST176
FXUS63 KLMK 010817
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
317 AM EST Wed Jan 1 2025
.KEY MESSAGES...
* Cold temperatures today with highs not making it out of the 30s. A
few lingering flurries or patches of drizzle. Lows in the 20s
tonight.
* A quick-moving disturbance will bring a chance for light snow
Thursday night into Friday morning. Minor travel impacts at rush
hour Friday morning are possible from southern Indiana to the
Kentucky Blue Grass.
* A stronger storm system will move across the region Sunday into
Monday. Forecast confidence remains low, but significant impacts
from mixed wintry precipitation are possible. Cold air then moves
in after this system.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 313 AM EST Wed Jan 1 2025
Expecting fairly quiet weather in the short term as yesterday's (or
should I say last year's???) system pushes through New England.
Meanwhile, surface high pressure steadily builds into our area
beneath zonal flow aloft. We do have lingering low level moisture in
the 1000-850 mb layer which is presenting as an expansive stratus
deck across our region and much of the Midwest/Upper Midwest. This
moisture is just deep enough to continue hanging onto some patches
of drizzle across the NE half of our CWA for another few hours this
pre-dawn. Then, we'll have mention of some lingering flurries or
sprinkles along and NE of a line from a Madison, IN to Richmond, KY
today. This is where that low level moisture remains just deep
enough, and a handful of models depict some very light QPF blips
through the day. Over the rest of our CWA, we do expect to hang onto
lingering stratus and stratocu, but moisture should be a bit too
shallow to support any very light precip.
The combination of continued cold advection on steady WNW to W
winds, the cloud cover, and a cold start to the day should result in
temps not making it out of the 30s for highs today. Will go with mid
to upper 30s, with perhaps a few peeks at the sun down near the
Bowling Green region late afternoon. Perhaps they touch 40 degrees
down there, but leaned on the more pessimistic side of guidance for
now. May also see a few gusts up in the 20 to 25 mph range today,
and will likely make temps feel like they are in the 20s.
Winds slacken a bit more tonight with skies trying to clear from W
to E across our area as surface high pressure gets more established.
This will result in lows well into the 20s for most. Will put a
range of 25 to 30, but won't be surprised to see some low 20s in
spots if the clearing and slackening winds are realized.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 313 AM EST Wed Jan 1 2025
We're still looking at two main weather makers in the Long Term: a
quick hitting minor system Thursday night/Friday morning, and a
significantly impactful system Sunday-Monday.
Act 1: Thursday Night - Friday morning
A quick-hitting system will swing through the Ohio Valley during
this period. Upper and mid level moisture will bring clouds to the
region Thursday afternoon/evening, but dry low level air will
prevent any hydrometeors from reaching the ground. Low levels
moisten up by late Thursday night into early Friday morning, but by
then the mid-and upper RH will have moved off to the east, resulting
in only shallow moisture for any precipitation to work with. As a
result, QPF is very light, and some guidance suggests we may not see
any measurable precip at all. However, the most likely timing for
any precip would be right around rush hour Friday morning and ptype
would likely be light snow or flurries, which could still have the
potential of 0.1-0.2" of accumulation. There won't be any rain in
advance of the -SN so roads should be dry, and at this time it
appears there should be little if any impact. The most likely area
to see a dusting of snow on elevated surfaces would be from southern
Indiana to the Kentucky Blue Grass.
Intermezzo: Friday afternoon - Saturday Night
A strong ridge of Canadian high pressure will nose its way SSE from
the Prairie Provinces to the Bahamas, providing us with dry and
chilly weather. Lows Friday night and Saturday night will range from
the mid teens to mid 20s with highs on Saturday right around the
freezing mark.
Act 2: Sunday - Monday
Confidence continues to increase that an impactful winter system is
still in the cards for Sunday-Monday. However, the 500mb shortwave
trough that will be partly responsible for early next week's tricky
weather is still way out over the central North Pacific, south of
the Aleutian Low. As a result, confidence in any specifics of
timing/location/ptype remains about the same. Confidence will
(hopefully) start to increase once the system enters the RAOB
network Friday night.
Still, there are some things we can say. Looking at ensembles and
their individual members, there is general agreement that a strong
low level jet will bring a warm nose northward, leading to a
complicated ptype forecast. Currently sticking with the traditional
R/S mix in the forecast given so much uncertainty, but multiple
wintry precip types will likely be needed eventually as we sit in
the precip transition zone of this system. Also, there is general
agreement that the most likely area for any significant snow will be
in Indiana and north central Kentucky, though there is still a very
large range in amounts from the 10th to 90th percentiles. Timing
this system is another problem, but it looks right now like the most
likely timing for the most impactful wintry weather will be Sunday
night. Stay tuned.
Coda: Beyond the 7-Day Forecast
Looking a bit farther ahead...as has been well advertised, the
second week of January is still looking quite cold. If this upcoming
Sunday-Monday system can establish a snow pack, that would further
support the idea of very cold weather to follow.
&&
.AVIATION /06Z TAFS THROUGH 12Z THURSDAY/...
Issued at 1244 AM EST Wed Jan 1 2025
Low MVFR ceilings are likely to persist through this morning,
followed by gradual improvement this afternoon. We'll keep some
patches of drizzle mentioned for another couple of hours before we
likely see a drying trend for the rest of the night. The other issue
for the overnight into tomorrow will continue to be gusty winds,
although not as prominent as yesterday. Look for steady W to WNW
winds around 10 to 15, with some occasional gusts up around 20-25
mph.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
SHORT TERM...BJS
LONG TERM...13
AVIATION...BJS
Source:
LMK issues Area Forecast Discussion (AFD) at Jan 1, 3:17 AM EST---------------
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