LMK issues Area Forecast Discussion (AFD) at Mar 23, 2:01 PM EDT288
FXUS63 KLMK 231801
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
201 PM EDT Sun Mar 23 2025
.KEY MESSAGES...
* Widespread showers, gusty winds, and scattered storms are expected
Sunday afternoon and evening as a cold front sweeps through the
region. Isolated wind gusts near 40 mph possible this afternoon
and evening. A few strong to severe storms possible across south-
central Kentucky late afternoon and evening.
* Near normal temperatures Monday through Thursday, with periodic
rain chances beginning Tuesday, and substantial dry periods in
between.
* Warmer temperatures and increasing chances for showers and storms
Friday into next weekend.
&&
.UPDATE...
Issued at 946 AM EDT Sun Mar 23 2025
Light rain is ongoing in southern IN this morning, mainly west of I-
65. Also starting to see some light rain reach the ground in our
northwesternmost KY counties. This precipitation is on the nose of a
45-50 kt SW LLJ, which will continue to stream east over the Ohio-
Mississippi River confluence this morning. Light rain will gradually
spread into areas slightly further southeast into west-central and
north-central KY through midday. Still have a healthy amount of dry
air to overcome in the lower levels (sfc dewpoints remain in the
20s/30s), so the lightest initial echoes on radar are virga.
The northwestern CWA that is seeing higher reflectivities aloft will
of course see the lower levels saturate faster this morning. Areas
further south and east will remain dry until this afternoon, when
low-level moisture advection increases as the warm front lifts
through the area.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 315 AM EDT Sun Mar 23 2025
It's a dry start to our Sunday, though showers and storms are
expected for later today as a shortwave trough pivots to a negative
tilt and deepens as it approaches the Great Lakes region. A Marginal
Risk for severe weather is on the table for a portion of our
area today, so let's get into the details.
The primary sfc low pressure system driven by the shortwave is
crossing the Northern Plains this morning, and will continue to spin
and deepen as it moves across the Great Lakes region today. A
trailing cold front will extend into the Midwest today, which is
expected to eventually arrive in our forecast area by late this
afternoon or evening hours. Elevated convection over Missouri early
this morning will weaken as it tracks across Illinois and Indiana,
and should have some radar returns later this morning.
Before the cold front arrives, a warm front will be swinging
northward and through our area, which will support increasing WAA
and isentropic ascent. Our airmass is fairly dry in the low levels,
so any initial radar echoes will likely be virga until the lower
levels become better saturated. As a 50kt LLJ works over the region,
our southerly flow will increase, resulting in strengthening sfc
winds, WAA, and moisture transport. Our sfc dewpoints are expected
to gradually rise from the 30s and 40s this morning into the 50s by
the afternoon. We continue to look quite stable and dry for most of
the morning hours, but as the warm front lifts through the area by
the afternoon, warm advective rain showers will spread across the
region. It's possible that some portions of the area could remain
mostly dry from any warm advective showers, with the Bluegrass and
perhaps the south-central KY counties the most likely areas.
Forcing and moisture increase throughout the afternoon when the cold
front pushes east of the Mississippi River. Rain should become more
widespread by then, with some embedded thunderstorms scattered
throughout possible. With a tight pressure gradient across the area,
and the LLJ mixing down higher momentum winds with any showers, wind
gusts will become gusty this afternoon. Wind gusts in the 30s most
likely, though some gusts near 40 mph are possible this afternoon
too.
Guidance has been consistent on a narrow line of stronger
convection forming just out ahead of the front, which could pass
through the area by the late afternoon and evening. With sfc
dewpoints maybe reaching the mid 50s, and sfc temps ranging in the
60s, we should be able to realize some very limited instability in
an already highly-sheared environment. Slightly warmer temps are
expected across south-central KY, possibly reaching the lower 70s,
which will further enhance any destabilization. The Marginal Risk
captures this well, but some tweaks to the outlook through the day
are possible, especially if we overachieve temps/dewpoints due to
WAA regime. A few damaging wind gusts will be the primary concern
with the line. Shear just ahead of the line will be mostly
unidirectional speed shear, though soundings in our southwest
forecast area do show a bit more directional shear possibly at play,
which do enhance hodographs some. This aligns well with a 2% tornado
risk drawn by SPC, which includes Bowling Green. Overall severe
potential does remain low, and any strong to severe storms would be
pretty isolated if they can even get developed in the first place.
Total rainfall from this event is still expected to be between 0.5-
1.0", though some isolated higher amounts could be possible with any
stronger storms.
The cold front will sweep through quickly by late this evening,
which will also push all precip out of the area. Cold air advection
will take over in the wake of the front, which will also usher in
drier air. Skycover will gradually clear overnight as high pressure
takes over to our west.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 315 AM EDT Sun Mar 23 2025
Broad eastern CONUS trof, with mainly NW flow aloft over the Ohio
Valley, will dominate the pattern Monday through Thursday. Temps
will run near normal through the period in the absence of any
intrusion of polar air.
Deep mixing and fast westerlies will make for a breezy Monday, with
sustained 15-20 mph sfc winds and gusts around 30 mph. This pattern
supports overachieving temps, so will work on the higher end of
guidance for afternoon highs. Naturally this leaves some potential
for a dry air mixdown, but fire wx concerns will be mitigated
somewhat after Sunday's rain.
A couple of weak ripples in the upper flow will round the base of
the trof both Tuesday and Wednesday, resulting in rain chances
across the Ohio Valley. Moisture supply is lacking without a real
Gulf moisture tap, so it's a low-probability (20-30 percent) and low-
QPF (less than a tenth of an inch) event.
By Friday upper heights build across the region and the faster NW
flow remains solidly to our north, while the southern stream becomes
a bit more active. Overall unsettled pattern is expected to develop
heading into next weekend, but timing and intensity of any wave of
precip will depend on the degree of phasing between the northern and
southern streams. Broad low-level southerly flow will draw milder
air and more moisture into the Ohio Valley, supporting chances for
thunder, but at this point will hold off any more widespread precip
beyond Day 7 Saturday. Temps will run well above normal Friday and
Saturday with highs solidly in the 70s and lows in the 50s.
&&
.AVIATION /18Z TAFS THROUGH 00Z TUESDAY/...
Issued at 200 PM EDT Sun Mar 23 2025
Rain showers continue to push through the area this afternoon.
Flight categories have mainly been VFR with moderate rainfall
bringing VIS to MVFR flight categories. These light rain showers
should continue off and on through the rest of the afternoon. Winds
have been struggling to reach the forecast levels but are still
possible if we can get some clearing. Strong LLJ will also work over
the area so some LLWS is also possible for SDF to LEX. The area
where confidence has dropped some is for the chance of thunder later
this afternoon and evening as a cold front works across the area.
The best chance for thunderstorms appears to be around BWG/RGA with
less likely chances to the north. Skies will clear and winds will
shift out of the west before returning to the WSW tomorrow. Winds
will once again increase in the afternoon.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
UPDATE...EBW
SHORT TERM...CJP
LONG TERM...RAS
AVIATION...BTN
Source:
LMK issues Area Forecast Discussion (AFD) at Mar 23, 2:01 PM EDT---------------
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