LMK issues Area Forecast Discussion (AFD) at Dec 30, 6:58 PM EST ...Updated Aviation Discussion...611
FXUS63 KLMK 302358
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
658 PM EST Mon Dec 30 2024
...Updated Aviation Discussion...
.KEY MESSAGES...
* Another period of rain is forecast for tonight into Tuesday
evening.
* Gusty winds in the 30-40mph range expected for Tuesday.
* Colder air arrives for the new year. A quick-moving disturbance
may bring a light dusting of snow Friday morning.
* A more impactful storm system may affect the region early next
week, especially in the Sunday-Monday time frame. Wintry
precipitation may be in play, including ice. Keep an eye on the
forecasts this week concerning this potential system.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 304 PM EST Mon Dec 30 2024
A low pressure system ejecting out of the Central Plains will bring
another round of rain and gusty winds to the area beginning tonight
and persisting through most of the day Tuesday.
Currently, surface analysis shows high pressure over the OH/TN
Valleys with a 981mb low pressure centered over central KS. Current
radar is quiet, but GOES-16 satellite continues to show low clouds
struggling to dissipate. KY Mesonet and regional observations are
reporting temperatures in the low to mid 50s under light mainly
southerly winds.
For this afternoon and evening, expect dry conditions to continue
with breaks in the clouds before skies begin to fill again with
encroaching mid and high cloud ahead of the aforementioned low
pressure system to our west. Rain showers enter the area a few hours
after midnight and will remain in play for the remainder of Tuesday
with rainfall totals likely falling around a third of an inch or
less, higher amounts expected across southern Indiana and within the
Bluegrass region.
Winds will also pick up overnight as a 50-55kt LLJ whips around the
850mb low center. Tight PGF will result in SE winds with gusts in
the 20-25 mph range overnight and into Tuesday morning before
increasing Tuesday afternoon into the 30-40 mph range. Not as windy
as this past weekend, but another breezy day for sure.
Temperatures will fall overnight into the mid 40s and rebound back
into the low to mid 50s for Tuesday afternoon. This will be the last
warm day for a while, unfortunately conditions won't be ideal for
enjoying them.
&&
.LONG TERM /TUESDAY THROUGH MONDAY/...
Issued at 304 PM EST Mon Dec 30 2024
Tuesday - Tuesday Night...
A progressive shortwave and its associated surface low will quickly
move from the Wabash River Valley Tuesday to New England by sunrise
Wednesday. Light rain showers will be ongoing for Tuesday, and then
will hold onto a few light showers or patchy drizzle into Tuesday
night. Expected rainfall amounts aren't very impressive given the
lack of deep moisture (only confined to the 1000-700mb layer), but
still coverage should be pretty widespread (80-90%) on Tuesday, at
least across our northern half of the CWA. Across our southern CWA,
coverage is expected to be more in the scattered to numerous range
(50-70%). Any additional rainfall amounts on Tuesday - Tuesday night
likely will be .15" or less.
The passing system does drag a cold front through the region, so
after a mild start to Tuesday temps will be rapidly falling by
Tuesday night. In fact, temperatures will likely not follow a
typical diurnal trend on Tuesday afternoon, and will likely start to
fall during the afternoon hours on gusty W winds. Look for late
morning to midday highs in the low to mid 50s, before temps fall
into the low to mid 30s by dawn on Wednesday. Given the steepening
low level lapse rates, we could end up with some 25 to 35 mph gusts
based off forecast soundings. Interestingly, LREF/NBM probs aren't
overly excited about the probabilities of any winds over 30 to 35
mph. Will be looking for some clarity with respect to that in the
coming forecasts. The other thing that will have to be watched for
is whether the cold air early New Year's Day catches up with any of
the lingering moisture. Right now, this looks like the less likely
scenario.
Wednesday - Thursday...
Should see a drier trend for Wednesday, and especially Thursday as
surface high pressure builds in behind the cold front, and dry zonal
flow aloft controls our region. Can't rule out a few more lingering
patches of drizzle into Wednesday if low level moisture holds on,
but will keep an optimistic forecast for now with improving chances
for some sunshine into the afternoon. Temps will be notably cooler
with highs in the upper 30s and low 40s for highs on Wednesday and
Thursday. Overnight lows on Wednesday night will also be much
cooler, and back in the 20s. Something we haven't seen since before
Christmas.
Thursday Night - Friday...
A quick hitting mid level disturbance continues to consistently show
up in the data for Thursday night into Friday across our northern
CWA. Thermal profiles look like they will be cold enough to support
snow during that stretch. As a result, will continue to carry some
mention of that possibility. At this point, the moisture looks
pretty limited, and would only be comfortable mentioning the
possibility of a dusting. Lows will again be in the 20s, with highs
on Friday likely not making it out of the 30s. Perhaps the KY/TN
border could touch 40.
Friday Night - Sunday...
The first part of the weekend looks to be continued cold and drier
as NW flow aloft once again controls the upper pattern, and no
notable shortwaves look to move through the flow. After lows in the
upper teens and low 20s on Friday night, Saturday morning highs look
to struggle in the low and mid 30s. Similar lows then occur again
Saturday night. This cold air in place for Saturday night could set
the stage for an impactful storm system heading into Sunday.
Confidence isn't overly high in specific details at this point,
however it can be noted that at least some signal for a potentially
impactful storm system later Sunday into Monday continues to show
itself in different forms on various deterministic runs. Confidence
is pretty high that cold air will be in place ahead of this
potential system, so the chance for at least some wintery weather on
the front end of the system has medium confidence. From there, much
will depend on the strength of the surface low and it's eventual
track on how p-type progresses through the rest of the system. There
is also a scenario where we don't see an impactful storm, as some
models still show. For now, will continue to advertise a wintry mix
to end the weekend.
&&
.AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 657 PM EST Mon Dec 30 2024
A strengthening low pressure system moving across the Ohio Valley
tonight into Tuesday is expected to bring impactful CIGs, VIS, gusty
winds, LLWS, and rain showers (possibly with embedded thunder)
during the current forecast period. There is relatively high
confidence in VFR conditions this evening, with the main impact
being increasing LLWS (especially at BWG) after 02Z as a 50 kt LLJ
moves into the region. This LLJ will eventually translate to the
surface by early Tuesday morning, bringing gusty winds which will
veer from SE to SW to NW through the forecast period.
After 06Z tonight, scattered rain showers with embedded
thunderstorms will move across the area, with the greatest chance
for thunder at HNB and SDF. Occasional MVFR CIGs and VIS are
possible in the heaviest rain showers. After the initial wave of
SHRA passes through, a brief break in precipitation is likely around
12Z Tuesday, and VFR CIGs and VIS are likely at all sites but HNB
for a brief window. However, CIGs and VIS are expected to fall
through the day on Tuesday, with IFR/low MVFR CIGs and MVFR VIS with
SHRA and drizzle expected toward the end of the current forecast
period.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
SHORT TERM...CG
LONG TERM...RJS
AVIATION...CSG
Source:
LMK issues Area Forecast Discussion (AFD) at Dec 30, 6:58 PM EST ...Updated Aviation Discussion...---------------
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