466
FXUS63 KLMK 121359
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
859 AM EST Wed Feb 12 2025

.KEY MESSAGES...

*  Lingering slick spots possible this morning, especially on
   untreated bridges and overpasses.

*  Additional chances for precipitation today and tonight, but this
   precipitation will be all rain and between 0.25-0.75 inches over
   most areas.

*  Widespread significant rains Friday night through Saturday night,
   ending as some light snow Sunday. Rainfall amounts are expected
   to range from around 2.50" in southern Indiana to 5" near the
   Tennessee border. Rains of that magnitude would pose a serious
   threat of both areal and river flooding.

&&

.UPDATE...
Issued at 858 AM EST Wed Feb 12 2025

Light drizzle continues to fall this morning, with air temperatures
mostly in the 32-35 degree range in southern Indiana and
northeastern sections of central Kentucky. Pavement temperatures in
the Bluegrass range from the mid 30s to low 40s, and traffic maps
show traffic moving smoothly. No road surface treating is being
performed by KYTC at this time. After coordinating with JKL and ILN,
will let the headline expire on time.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 334 AM EST Wed Feb 12 2025

Pockets of light radar returns continue across our CWA at this hour,
and with temps hovering right around freezing there remains a threat
for some very light freezing rain or freezing drizzle. Continue to
see some light icing obs showing up on the LEX ASOS, and expect it
is probably happening in other locations as well, especially on
elevated surfaces. As a result, plan to extend the Winter Weather
Advisory through the morning commute to get temps above freezing.
So, Winter Weather Advisory will now be in effect until 14z in
coordination with JKL/ILN. Do think a few spots in the Advisory
could see a glaze to a tenth of an inch of ice on elevated surfaces.

Time heights and forecast soundings continue to advertise lingering
1000-700 mb moisture through the short term, and this will be in the
presence of a weak but persistent isentropic lift component. There
will be pockets/periods of dry weather, but pretty hard to nail down
any dry times for any given place at any given time in the short
term. So, will continue with mentionable pops through tonight as the
isentropic lift and 1000-700 mb continue, and a surface low move
into our region with renewed low level jetting ahead of it. Do have
categorical pops for the area, with most folks expected to get
between .25" and .33" of additional rainfall. Could see a half an
inch of rainfall in our far SE CWA, but it looks like the heaviest
rainfall should mainly stay south and east of the CWA. Will note
that the 12/00z NAM does show a heavier swath of QPF across
Cumberland/Clinton counties for later tonight, but given that HREF
PMM values do not match the NAM solution, will consider it the
outlier for now. Will continue to monitor through today to make sure
some heavier amounts don`t materialize. If so, may need a short-
lived Flood Watch in that area.

Expect a pretty decent gradient in high temps today as a surface low
is expected to work right up through our CWA. As a result, we`ll see
highs in the 50s across our south, with highs only in the 30s across
southern IN. Tonight, colder air moves in behind the departing
surface low/cold front, and we should see upper 20s and low 30 by
sunrise Thursday. At this point, it doesn`t appear the cold air
catches up to the lingering light rain/drizzle.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 334 AM EST Wed Feb 12 2025

Thursday - Friday

This will feature a period of dry and cooler weather for the end of
the week. While a weak shortwave aloft swings through the region
allowing cold air to advect in, sfc high pressure will build in from
the west. Clouds are likely to linger during the day Thursday but
will slowly thin out and clear later in the day. With a steady
northwest wind, temperatures in the 30s will have a wind chill in the
20s. High pressure will continue to build over the Ohio Valley
Thursday night into Friday. Winds will diminish and with clear skies
temperatures Friday morning will be chilly with lows in the teens
and a few 20s along the KY/TN border. Temperatures will rebound into
the 40s on Friday as ridging begins to build in over the region
ahead of the next approaching system. Clouds will also be on the
increase for later into the day and Friday night.

Friday Night - Saturday

A deep upper trough will work eastward out of the Four Corners
Friday night into Saturday. While a sfc low develops and deepens
over the Ark-La-Tex Saturday evening and quickly works northward into
central KY Saturday night. Ahead of this system a strong LLJ will
develop ahead of this system and transport deep Gulf moisture into
the region. PWAT values will increase to around 1.50" to potentially
as high as 1.75" resulting in widespread rain showers with some
being heavy at times. The main concern with all of this is the
increased flooding potential both with area river and streams as
well as localized flash flooding. Forecast rainfall amounts continue
to range between 2.50" around southern IN to  4.00"/5.00" inches
across southern and central KY. Models seem to becoming closer on a
solution on the location and timing on the sfc low with just a few
minor discrepancies. The low still looks to track right over the
Commonwealth Saturday night with an axis of heavy rain associated
with it. WPC in their Day 4 ERO will put most of the CWA in a
Moderate Outlook which only reinforces the messaging we`ve had the
last couple days for the potential of flooding for Saturday into
Sunday. While the main concern and threat remains flooding, not
going to rule out that there could be some embedded thunder Saturday
night as the sfc low works over the region. While the severe threat
looks low, any convection would help to increase potential rain
rates and localized flash flooding. You can find more in our hydro
section below.

Sunday - Early Next Week

Sfc low pushes east-northeast Sunday morning allowing for colder air
to advect in behind it. Depending on quickly the cold air will
arrive and how much moisture wraps around the system there could be
a period of light snow on the back side of the departing system. The
main story for Sunday into early next week will be the colder air.
Highs will be in the 30s with lows in the teens. There is a chance
of some light snow Tuesday into Wednesday as a weak shortwave moves
into the region.

&&

.AVIATION /12Z TAFS THROUGH 18Z THURSDAY/...
Issued at 627 AM EST Wed Feb 12 2025

Seeing solid IFR conditions at all TAF sites at this hour, and even
some ceilings down close to minimums at times. Overall, expect very
poor conditions through this entire TAF cycle as low ceilings,
reduced visibilities, and drizzle/rain all have impacts.

There will be breaks in the precipitation at times, but overall hard
to find a time to mention where there won`t be light precip chances,
so leaned on the more pessimistic side. Guidance is also quite
pessimistic with low ceilings later this morning into the afternoon,
and do have some vis values also down close to minimums. Otherwise,
look for steady NE winds this morning, veering to SE winds this
afternoon as an area of low pressure begins to approach the area.
Winds will go variable late in this cycle as the surface low begins
to move through. Late in this forecast cycle, the surface low and
cold front pass, and we`ll see a steady W to WNW wind 10 to 15 mph.
A few gusts up around 20 mph will be possible. Conditions will
slowly improve toward sunrise on Thursday and we`ll begin to dry
out, but it may take some time to recover ceilings out of the solid
IFR.

&&

.HYDROLOGY...
Issued at 334 AM EST Wed Feb 12 2025

We`ll continue to see lingering drizzle and light rain this morning,
before another wave of rainfall arrives later today into tonight. An
additional 0.25"-.75" inches of rain is expected. While rains of
this magnitude may not create flooding on their own, they will serve
to keep soils saturated, streams high, and metl any lingering snow
left over from Tuesday`s system.

A third, and likely the most impactful, system will arrive this
weekend, with another 2 to 4 inches of rain in the forecast. Central
and southern KY are currently expected to see the higher totals out
of this wave as well. Overall, total rainfall amounts through next
Sunday could range between 2 and 3 inches across southern Indiana
and north central KY, and 3-5 inches in southern Kentucky.

With already saturated soils, and area rivers and streams continuing
to run high, these waves of rain will make areal flood and river
flood threats increase as we move through the week. The river basins
that stand the biggest threat of widespread minor flooding, and
higher impacts, would be the Green, Rough, Rolling Fork,
Cumberland, Kentucky, and Licking. The Ohio River will also see
notable rises with added rainfall and contributions from
tributaries. All of these streams will be subject to minor
flooding, and there`s about a 30-50% chance of some spots
reaching moderate flooding on the Kentucky River. A moderate
risk of excessive rainfall has been outlooked for much of
central and southern KY by the Weather Prediction Center.

Stay up to date of the latest forecasts during this active and
impactful stretch of weather.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.

&&

$$

UPDATE...13
SHORT TERM...BJS
LONG TERM...BTN
AVIATION...BJS
HYDROLOGY...BJS/BTN