Lexington, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

169
FXUS63 KLMK 120734
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
334 AM EDT Thu Jun 12 2025

.KEY MESSAGES...

*  Low chances for showers and thunderstorms return this evening
   across southern Kentucky.

*  Greater chances for rain, with widespread coverage of showers and
   storms, are expected Friday into the weekend. Heavy rainfall and
   localized flooding are the main concerns with storms.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 333 AM EDT Thu Jun 12 2025

This morning, dry and mild conditions continue across central
Kentucky and southern Indiana as surface high pressure has gradually
drifted over the central Appalachians over the past 12 to 24 hours.
Convective debris clouds from showers and storms over the southern
Plains continue to drift across the region from southwest to
northeast. These clouds and light southeasterly flow have tempered
the drop in temperatures slightly compared to previous nights;
however, temperatures have still fallen into the low-to-mid 60s in
many locations as of 07Z. Regional AWOS/ASOS sites as well as
Mesonet cameras show that fog is less widespread and less dense than
previous nights; however, still included a mention of patchy fog in
the area river valleys through sunrise.

Today, a closed upper low centered near OKC this morning will drift
to the north and east, approaching the Ozarks tonight. As it does
so, combined upper-level and sfc ridging will slide east of the
Appalachians, with modest southerly and southwesterly flow spreading
across the region. This will bring richer moisture into the area
from the Gulf and the lower Mississippi Valley, with dewpoints
remaining in the 60s this afternoon. This increase in low-level
moisture will make conditions more favorable for precipitation to
develop, although warm air in the mid-levels will limit convection
today. However, hi-res guidance is hinting at a shower or two
popping up across Lake Cumberland and south central KY this
afternoon, so we`ll carry a slight chance PoP with this forecast.
Temperatures today should be the warmest so far this week, with mid-
to-upper 80s expected across the area. 90 degrees can`t be ruled
out; however, thickening upper level clouds may limit temperatures.
Light southerly winds are expected between 5-10 mph this afternoon.

Tonight, as the low pressure system creeps farther to the east, a
strengthening height gradient over the region will increase
southerly flow, and will also increase low-level moisture. Along the
leading edge of a 925-mb theta-E surge, a band of showers and maybe
a few storms is expected to develop this evening to our southwest.
As we lose daytime heating, this band should weaken; however,
scattered showers may make it into areas along and west of I-65 in
the early morning hours on Friday. Cloud cover will continue to
increase into Friday morning, and a light southeast wind overnight
will also help to keep temperatures up. Lows Friday morning will be
mild, only falling into the upper 60s and lower 70s.

&&

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
Issued at 333 AM EDT Thu Jun 12 2025

Friday through the Weekend...

On Friday, synoptic scale upper level troughing is expected across
the Gulf of Alaska as well as over the Canadian Maritimes, with
broad, flat ridging in place over much of the CONUS. However, a
cutoff upper low over the southern Plains today will meander towards
the Ozarks and into the mid-Mississippi Valley on Friday along with
an associated sfc low. In the vicinity of the cutoff low, a tropical
air mass will be present, with PW values expected to range between
1.75-1.9" across the Ohio Valley, with isolated spots around 2". For
context, this exceeds the 90th percentile of ensemble climatology in
both the Euro and GFS/Canadian ensembles.

Model soundings generally show moisture spread through a fairly deep
layer, and fairly widespread cloud cover is expected for Friday into
the weekend. As a result, instability will be limited, as sounding
profiles show "tall, skinny CAPE" which is typically more supportive
of efficient rainfall than severe weather. Wet-bulb zero heights in
excess of 14 kft will also support efficient warm cloud rainfall
processes, and storm motions will be relatively slow, especially
Saturday evening into Sunday as the closed low passes over the
region.

With this being said, the triggering mechanisms for showers and
storms will be fairly subtle, and in general, showers and storms
should be fairly disorganized given weak to occasionally modest deep-
layer shear. Accordingly, while PoPs are fairly high from Friday
through Sunday, the weekend shouldn`t be a washout, and there will
be significant stretches of dry weather in between rounds of showers
and storms. Precipitation coverage will generally be at a maximum
during and just after peak heating (i.e., afternoon and evening
hours), with lower chances for rain overnight and during the
morning. Basin average rain amounts should be around 1" over the
weekend; however, there will be considerable variability from
location to location, and given the high moisture content and
efficient rainfall, localized heavy rainfall amounts are possible,
and could result in some flooding.

With the moist air mass in place, diurnal ranges will be suppressed,
with highs Friday through the weekend generally in the low-to-mid
80s and lows in the upper 60s and lower 70s.

Early-to-Mid Next Week...

Sunday into Monday, the upper low will gradually get absorbed back
into the zonal flow regime over much of North America with the
associated sfc low also weakening during this period. PW values will
drop somewhat on Monday, and while afternoon/evening showers/storms
are still possible, coverage should be less than over the weekend.

The pattern will shift slightly as we head into the middle of next
week as the upper level jet over the north Pacific is expected to
elongate and spread eastward into the Pacific NW. As a result, upper
ridging over the desert SW this weekend will spread eastward across
the Plains, assisting in bringing height rises across the Mississippi
and Ohio Valley. This area of ridging is generally expected to
remain fairly flat through next week, with the GFS/GEFS building the
ridge across the center of the country more than the ECMWF/EPS.
Downstream of the Pacific jet, multiple shortwaves are expected to
slide across the northern US through the middle of next week, firing
off waves of showers and storms, potentially MCSs. Machine learning
severe weather guidance does show a weak signal for strong storms
across the Midwest during the middle of next week; however,
confidence is low at this time.

Depending on how much the ridge builds next Tuesday and Wednesday,
our area may see decreasing rain chances or continued waves of
showers and storms, with a stronger ridge supporting the drier
solution. Regardless, with increasing heights to our southwest,
temperatures should increase next week, with highs expected to
approach the upper 80s to around 90 by the end of the current
extended forecast period.

&&

.AVIATION /06Z TAFS THROUGH 12Z FRIDAY/...
Issued at 113 AM EDT Thu Jun 12 2025

Surface high pressure over the Appalachians will bring continued
light and variable winds through the morning hours with scattered
cirrus streaming into the region from the southwest. Still can`t
rule out brief visibility drops from patchy fog around sunrise,
particularly at HNB and BWG. Southerly flow of around 5-10 kt will
return for the afternoon hours as high pressure moves east. While a
few daytime cu may develop in the afternoon, ceilings should remain
above 10 kft through the current forecast period, and VFR conditions
are expected.

&&

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

&&

$$

SHORT TERM...CSG
LONG TERM...CSG
AVIATION...CSG