National Weather Service Raw Text Product

118 
FXUS63 KLMK 130552
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
1252 AM EST Thu Feb 13 2025

...Updated Aviation Discussion... 

.KEY MESSAGES...

*  Widespread rainfall Friday night through early Sunday will likely 
   lead to area river flooding. Falling temperatures on Sunday could 
   cause light snow to mix in on Sunday.

*  Another system could bring additional snow showers on Tuesday and 
   Wednesday of next week.

&&

.UPDATE...
Issued at 943 PM EST Wed Feb 12 2025

It is quite a gloomy and damp night, thanks to the sfc low passing 
through the area. This sfc low is directly over north-central 
Kentucky this evening, evident by sfc obs showing the wind shift 
approaching I-65, and KLVX radar picking up the trailing frontal 
boundary across central Kentucky. SDF is actually reporting a calm 
wind right now, which is not something you see often there. 

Expect these dreary conditions to continue tonight as the low 
gradually departs. Drizzle, fog/mist, and low clouds will continue, 
though as the moisture transport shifts eastward with the front, so 
will the worst conditions. Cold NW flow is already filtering in to 
our west, and it is quite notable on the Kentucky Mesonet. 1000-850 
fgen band along the front will help support continued light precip 
for the overnight period. However, it is expected that most precip 
should be exiting as the colder air finally arrives. There could 
still be a brief overlap to cause some freezing drizzle tonight, but 
fortunately the moisture availability will be limited enough to not 
raise concerns about impacts. As for precip ending time, areas west 
of I-65 should be free of any precip chances by 06z, but it will be 
after 09z by the time the folks in the Bluegrass or I-75 corridor 
finally get drier conditions. 

The forecast remains in good shape for tonight, so no major changes 
are planned.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 335 PM EST Wed Feb 12 2025

Low pressure crossing central Kentucky from south to north this 
evening will be accompanied by widespread showers. Fortunately 
amounts will be light, in the 0.10-0.30" range. A few rumbles of 
elevated evening thunder can't be entirely ruled out in the Lake 
Cumberland region with some meager instability showing up on 
sounding progs.

As the low pulls off to the eastern Great Lakes by morning, 
precipitation will come to an end though the low overcast will 
persist. Temperatures will drop below freezing in southern Indiana 
and about the northwest half of central Kentucky, but at this time 
it looks like the precipitation should end before that 
happens...though it will be close. 

Areas of fog can be expected as well, with the most widespread fog 
likely during the evening hours. After midnight WNW surface winds 
behind the departing low pressure center will increase to around 10 
to 15 mph, reducing fog chances.

Tomorrow the center of a strong dome of high pressure will cross 
from Kansas to Missouri. The surface pressure gradient ahead of this 
high will be fairly tight and will support wind gusts of 20-25 mph. 
Low clouds trapped under a strong low level inversion will continue 
to blanket our skies for the bulk of the day, though WNW 925-850mb 
flow and the approach of the high may introduce enough drier air to 
let us have a few peeks of sunshine just as the day comes to a 
close. Highs will be in the 30s.

For those with concerns regarding the flooding expected this 
weekend, tomorrow and Friday will be the last days to bring 
preparations to completion. (See below)

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 335 PM EST Wed Feb 12 2025

On Thursday night, a mildly amplified upper trough over the Ohio 
Valley will guide a large surface high through the CWA. This will 
keep winds light under clear skies, allowing temperatures to fall 
into the teens to low 20s. Clear skies remain into the first half of 
the day on Friday, but sunny skies will only allow temperatures to 
reach into the upper 30s across southern Indiana to the upper 40s in 
southern Kentucky along the Tennessee border. 

Friday night, an upper trough surging southward through the 
Southwest will drive a surface low east from eastern Colorado. The 
low will strengthen and expand as it moves east towards the Ozarks. 
This will force winds over the CWA to veer towards the south late in 
the night, increasing warm air advection and moisture into the area 
associated with a warm front ahead of the low. A 50+ knot low level 
jet will concurrently move into the area. Precipitable water values 
are expected to climb to around 1-1.25" with a few pockets of higher 
values possible.   

Model soundings show deep layer saturation with no real instability, 
so we aren't looking at storms or the really high rainfall rates 
they bring. The stratiform rain isn't expected to cause any flash 
flooding, but depending on amounts and location, river flooding is a 
concern. Most current models have the axis of highest rainfall 
totals falling across south central Kentucky through the Lake 
Cumberland area towards the Bluegrass region before on to eastern 
Kentucky, but the Euro and GFS have trended slightly towards the 
north with this axis of highest totals. The GFS still holds on to 
the highest totals being across south central and eastern Kentucky 
while the Euro places the axis of highest totals closer to the Ohio 
River. It's worth noting overall totals are lower with the Euro, and 
now that the NAM has picked up on part of the event, it also places 
the highest totals closer to the Ohio River. For now, believe most 
in central Kentucky will see between 3-4 inches of rainfall between 
late Friday night and Sunday evening. A few isolated areas could see 
5+ inches. Those north of the Ohio River in southern Indiana are 
expected to see a little less, between 2-3 inches.  

Saturday night, a cold front associated with the system will push 
through the region. This will veer winds towards the northwest, 
increasing cold air advection. This could cause some snow to mix in 
with the rain on any remaining precipitation, but a delay in these 
cooler temperatures would keep all the precipitation as rain before 
ending.

High surface pressure behind the front will usher in cooler 
temperatures with highs in the 30s to low 40s and nightly lows in 
the teens to 20s through midweek. As the next expected system 
arrives for Tuesday and Wednesday, another round of light snow 
appears likely.

&&

.AVIATION /06Z TAFS THROUGH 12Z FRIDAY/...
Issued at 1250 AM EST Thu Feb 13 2025

Most terminal locations continue to show IFR flight categories and 
likely will through the overnight into the early morning. Sfc low 
has lifted into Ohio dragging a sfc cold front through central KY. 
Lingering areas of lgt rain/drizzle will bring VIS down at times as 
well as keep low IFR CIGS around. Sfc high pressure over the Northern 
Plains will build in from the west bringing drier air into the area. 
Low clouds will linger as we go into the morning so IFR to MVFR 
flight categories will be around during the morning and into the 
early afternoon as clouds slowly mix and thin out over the region. 
VFR conditions will return by late afternoon into the end of the 
period.

&&

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

&&

$$

UPDATE...CJP
SHORT TERM...13
LONG TERM...KDW
AVIATION...BTN