Berea, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

178
FXUS63 KLMK 301725
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
125 PM EDT Sun Mar 30 2025

.KEY MESSAGES...

* Severe storms expected this evening into tonight, which will be
  capable of all severe hazards (wind, hail, tornado, locally heavy
  downpours). Some of these hazards may bring significant damage.

* Another strong low pressure system is expected to bring windy
  conditions to the region Wednesday, and thunderstorms, possibly
  severe, Wednesday evening into Wednesday night.

* Additional showers and storms are expected to continue from
  Thursday into the weekend. There is increasing concern for a high-
  impact heavy rainfall and flooding event across the lower Ohio and
  Tennessee valleys from Wednesday night through next weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 343 AM EDT Sun Mar 30 2025

This Morning...

A 1000 mb sfc low over southern IA this morning will continue to
rotate northeast, dragging a trailing cold front through portions of
IL, MO, AR, and OK. Deep SW flow remains in place downstream across
the MS and OH Valleys. A weak shortwave impulse is currently lifting
northeast over KY, as is a 45-50 kt SW low-level jet. This lead
shortwave and robust low-level moisture advection are responsible
for scattered to numerous showers spreading NE over southern IN and
central KY this morning. This more coherent band of showers will
lift off to the northeast through sunrise, with spottier shower
coverage in the wake of the departing shortwave and LLJ core.

Forecast soundings show a stable environment through the morning
hours, and the chance for a thunderstorm is slim. Temperatures will
settle into the low to mid 60s through daybreak, with breezy
southerly winds.


This Afternoon - Tonight...

***Severe Storms Capable of Producing Strong Tornadoes,
Damaging Wind, and Large Hail Expected This Evening and Overnight***

An upper level trough initially over the southern/central Plains
this morning is forecast to lift northeast in tandem with the sfc
low, reaching Lower MI by evening. The primary mid-level trough
axis/vorticity maximum will approach the Lower Ohio River this
evening, with a 70 kt 500 mb speed max streaming from the Ozarks
across southern IL/IN. Very strong diffluence aloft is noted over
our region at 00Z this evening due a coupled upper jet structure,
with the OH Valley favorably positioned beneath the left exit region
of a Pacific jet streaming across the southern CONUS, and the right
entrance region of the polar jet.

Robust SW flow in the lower levels will gradually moisten the
environment, and sfc dewpoints will continue to rise into the lower
60s. Forecast soundings continue to show an elevated mixed layer
spreading east over the Lower OH Valley during the daytime. Mid-
level lapse rates will gradually steepen during the afternoon hours
above a strengthening warm capping inversion. Thus, still expecting
only isolated to widely scattered (and shallow) shower activity
through late afternoon.

By mid-afternoon, however, we are likely to see deep convective
initiation upstream over the Mid-MS Valley in a moderately unstable
environment. Storms will initiate just ahead of the approaching mid-
level wave and strong sfc cold front. Some initial supercells and
multicells clusters are likely to grow into one or more line
segments as they approach southwestern IN. Depending on how this
convection evolves, could see a threat for a strong or severe storm
in our northwestern CWA as early as 21-23Z.

However, our primary severe weather threat is still expected to be
in the form of a severe QLCS which will surge through central KY and
southern IN between roughly 23-08Z (7 PM Sun - 4 AM Mon EDT). Latest
HREF data and forecast model soundings suggest around 1000-1500 J/kg
MLCAPE across the western 2/3 of the forecast area, with perhaps
500+ J/kg available in the Bluegrass and Lake Cumberland regions.
Deep-layer shear remains favorable for sustaining severe convection
at 40-50 kts. Low-level shear also looks pretty healthy with some
clockwise curvature in the lowest 1 km. Effective SRH should at
least approach, if not exceed 200 m2/s2. Damaging winds and strong
mesovortices are both concerns with the line, especially with any
bows or surges. The large hail threat has decreased some. There is
still a threat for severe (at least 1" diameter) hail, but
confidence is pretty low in significant hail (2" diameter or
larger).

The flash flooding threat is low for this event. Overall, it`s
pretty progressive with a narrow window for heavy rainfall rates.
However, with anomalous moisture present, these storms will be
efficient rain producers. The biggest concern with flooding is the
added soil moisture this convection will produce ahead of
potentially significant and high-impact rainfall/flash flooding
later in the week (see Long Term for the details).

Monday...

The cold front sweeps through the area Monday morning. One more
trailing mid/upper level trough will actually enhance shower chances
in the eastern forecast area during the daytime. Expect rain chances
to gradually taper off from west to east during the day. Otherwise,
expect a notably cooler, cloudy, and breezy Monday with temps
struggling in the 40s/50s amid strong cold air advection.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 343 AM EDT Sun Mar 30 2025

Monday Night - Tuesday...

Monday evening into Tuesday morning, the mid- and upper-level trough
which is bringing the active weather later today into tonight will
pass east of the Appalachians, with fairly zonal upper flow pattern
expected in its wake. At the surface, inverted pressure ridge
centered over Ontario will extend down into the Ohio Valley on
Tuesday, pulling east of the area by Tuesday night. Cold advection
on Monday will allow for below normal temperatures Tuesday morning,
with lows likely to fall into the 30s across the area. Any cold
advection should subside by Tuesday morning, with light east winds
and a mix of sun and high clouds allowing temperatures to warm into
the upper 50s and low-to-mid 60s Tuesday afternoon.

Tuesday Night - Wednesday Night...

The likelihood of another high-impact system is increasing across
the Ohio and Tennessee valleys for Wednesday into Wednesday night.
During the mid-to-late week period, longwave troughing will settle
across the western half of the CONUS, with embedded shortwaves
cutting across the Plains within broad SW flow aloft. The first of
these shortwaves will eject from northeast NM across the central
Plains Tuesday night. Sfc cyclogenesis and mid-level height falls
from the Plains eastward to the Mississippi valley will promote
strengthening southerly flow Tuesday night into the day on
Wednesday. This will allow for rapid, strong moisture return across
the region, with NAEFS/EPS ensemble mean vapor transport values
exceeding the 99th percentile of climo. Additionally, Wednesday
should be a windy day, with NBM 24-hr probabilities of max gusts
over 40 mph ranging from 60-90% across the CWA.

As a warm front lifts through the area Wednesday morning, scattered
showers and thunderstorms will be possible, with the best chances
north of the I-64 corridor. However, much of the day on Wednesday
should be dry as the heart of the warm sector and mid-level capping
spreads across the Ohio Valley. Within the warm sector, mid-60s sfc
dewpoints will allow for 1500-2500 J/kg SBCAPE, providing ample fuel
for storms. Strong SW mid-level flow coupled with southerly near-sfc
flow will provide more than sufficient shear and helicity for
organized convection. By mid-afternoon Wednesday, convection is
expected to initiate along a sfc front extending from western IL
down into eastern OK. Discrete convective modes would be favored
initially, with upscale growth into some sort of QLCS likely as
convection moves east Wednesday evening into Wednesday night.

All severe hazards are on the table Wednesday afternoon into
Wednesday night. Machine learning models from NSSL/CIPS/CSU continue
to highlight the lower Ohio Valley and mid-Mississippi valleys with
the greatest severe probabilities. If convection is able to initiate
further out in the warm sector Wednesday afternoon/evening, it would
be much more likely to remain discrete given the aforementioned
capping and more boundary-perpendicular deep layer shear. Any
discrete cells would carry an elevated tornado and damaging hail
threat. If the cap holds Wednesday afternoon and evening, then the
primary threats would be those associated with a QLCS which would
move across the region Wednesday evening into Wednesday night:
damaging winds and spin-up tornadoes. As has been the case with
several severe events recently, the overall severe potential should
begin to decrease east of the I-65 corridor, especially if
convection was to slow down and linger later into the nighttime
hours. Regardless, all areas across central KY and southern IN
remain under an elevated severe threat mid-week. Make sure to
monitor the latest forecast updates as changes in severe threat
levels and timing are possible.

Thursday - Next Weekend...

The pattern late this week into next weekend is particularly
concerning for heavy rainfall and flash flooding across the lower
Ohio and Tennessee valleys. As the leading upper shortwave which
brings the storms into the region Wednesday lifts into Canada, deep
SW flow aloft with a strong baroclinic zone will remain from west TX
to the mid-MS valley up into the lower Great Lakes. At this time,
ensemble guidance is in relatively good agreement positioning our
area just on the warm/moist side of this frontal zone, which will
unfortunately allow for repeated rounds of convectively-enhanced
rainfall for Thursday into at least the first part of next weekend.

As alluded to above, the air mass south of this boundary will be
unusually moist and unstable. ECMWF ensemble mean precipitable water
values Thursday into Friday exceed the maximum of model climatology,
with a narrow swath of PW exceeding 1.75" across the area. Model
soundings show that while the near-sfc layer should be stable,
lingering elevated instability could allow for convectively-enhanced
rainfall Thursday into Friday. On top of all this, soundings also
show deep warm cloud layers (wet-bulb zero heights 12-13 kft),
suggesting more efficient warm rain processes may be at play.

Multiple ensemble indices highlight the concern for heavy
rainfall/flooding issues across the region. The 29/12Z ECMWF Extreme
Forecast Index is around 0.9 with a shift of tails of 5 (!) on
Thursday. This suggests high confidence in unusually heavy rainfall
amounts with the highest ensemble members showing extremely
anomalous rainfall amounts. On top of this, on Friday, the EFI is
around 0.8 with a shift of tails of 1, indicating medium-high
confidence in anomalously heavy rainfall with that additional signal
of some highly anomalous outliers. Ensemble 25th-75th percentile 7-
day QPF amounts range from 5-9" in a swath from western TN up into
western and central KY, broadly in line with the WPC 7-day QPF
totals. As a result of this multi-day heavy rainfall threat which
could lead to significant flooding impacts, have coordinated with
WPC on the issuance of a Day 5/Thursday moderate risk for excessive
rainfall (in addition to a slight risk on Day 4/Wednesday).

With all this being said, as the system is still 4-5 days away,
subtle shifts in the swath of heaviest rainfall are likely, and the
greatest threat area may need to be modified. However, make sure to
monitor the latest forecast updates over the next several days given
the potential for a high-impact flooding event across the lower
Ohio/TN valley.

&&

.AVIATION /18Z TAFS THROUGH 00Z TUESDAY/...
Issued at 125 PM EDT Sun Mar 30 2025

Widely scattered thunderstorms are expected to pop this afternoon,
followed by a squall line this evening/early tonight with very
strong wind gusts, torrential rainfall, hail, and tornadoes all
possible. Ahead of the storms, southerly winds will be a bit gusty
today with gusts over 20 kt. Behind the storms MVFR ceilings are
expected to set in and remain into Monday morning with winds coming
in from the WNW.

&&

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

&&

$$

SHORT TERM...EBW
LONG TERM...CSG
AVIATION...13