LMK issues Area Forecast Discussion (AFD) at Apr 24, 6:24 AM EDT ...Updated Aviation Discussion...800
FXUS63 KLMK 241024
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
624 AM EDT Thu Apr 24 2025
...Updated Aviation Discussion...
.KEY MESSAGES...
* Showers and thunderstorms are in the forecast today through
Friday night. Severe storms are not expected, although 1 to 1.5
inches of rain is expected across southern KY.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 314 AM EDT Thu Apr 24 2025
Our area will be within a warm sector today due to a weak warm front
pushing north through the Ohio Valley. This will support slightly
more favorable moisture to advect up into our region from the south,
which will lead to isolated to scattered showers and storm chances
today, especially in the afternoon. Model soundings continue to
indicate marginal instability, with the HREF suggesting a 60-80%
chance for SBCAPE to exceed 1000 J/kg this afternoon. With
relatively weak flow in the column, wind shear parameters will be
quite weak, so organized convection will be hard to come by. No
severe storms are expected today. However, storm motions could be
somewhat slow, and with some heavier downpours possible due to
slightly elevated PWATs, some minor nuisance ponding issues could be
possible for poor drainage areas. Overall flooding threat will be
low though given the isolated-scattered nature of the precip today.
Temps will be warm again today thanks to WAA regime and southerly
flow, with highs peaking around 80 this afternoon.
For tonight, precip coverage should be much less as we lose daytime
heating, but a few showers may be possible late. Will hold on to a
roughly 20% chance for the overnight, but most of the area could be
mostly dry besides a few isolate light showers. Temps will be mild,
with lows remaining in the 60s.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 314 AM EDT Thu Apr 24 2025
Friday - Friday Night...
Looking at a hybrid setup to the end the week as multiple moisture
sources associated with differing features will pool around our
region. A stalled frontal boundary to our south will begin to lift
northward ahead of an approaching shortwave trough axis, bringing an
increase in Gulf moisture as the two features converge. In addition,
surface cyclogenesis will also be occurring over the Great Lakes
region ahead of a northern shortwave, which will drag a trailing
cold front into our area.
The end result will be several triggering mechanisms combining with
high PWAT values peaking in the 1.5 to 1.6" range later Friday into
Friday night. The end result will be periods of showers and
thunderstorms through that period, which will be capable of locally
heavy rainfall and perhaps some gusty winds. Forecast soundings take
on a tall/skinny profile in the high PWAT airmass, with overall deep
layer shear fairly weak. There may be just enough shear for some
loosely organized updrafts and a local severe threat, but the main
concern will probably end up being locally heavy rainfall thanks to
slow storm movement (20-25 mph), and efficient rainfall processes.
Will be watching the HREF PMM/LPMM products to look for some locally
heavy rainfall potential in the data as overall basin average QPF
values aren't overly impressive.
Cold front pushes through Friday night, with a gradual drying trend
from W to E toward dawn on Saturday. Lows on Friday night drop into
the 50s for most.
Saturday - Sunday Night...
Surface high pressure builds in behind the departing cold front and
will keep us dry through the remainder of the weekend. Notably
cooler temps will be observed, with highs only in the upper 60s and
low 70s on Saturday, and then recovering to the low and mid 70s by
Sunday. Chilly overnight lows mostly in the 40s will also be
expected for Saturday night.
Monday - Monday Night...
Surface high pressure retreats to the east by early next week,
meanwhile ridging will briefly be in place aloft. This should result
in a mostly dry and warmer period. Highs are expected to be back
mostly in the low 80s by this time. Can't rule out a stray shower or
two, but most precip chances should be held in check by a subsidence
inversion beneath the upper ridge. Sometimes models will spit out
some light QPF for vertical development between the LFC and
subsidence inversion, and that is likely what we are seeing here.
Expect a mostly dry forecast.
Tuesday - Wednesday...
We'll have to watch the mid week timeframe as a potential severe
weather setup could develop. Deeper SW flow aloft looks to set up
over our area between a trough west/ridge SE pattern. Meanwhile, an
eastern Canada surface low will drag a cold front toward our region.
This looks to be a fairly unstable setup ahead of the approaching
front, and with increasing deep layer shear in the deep SW flow
aloft. For the moment, the bulk of the activity looks to be to our
NW, with perhaps some favorable timing of arrival into our area in
the overnight hours (diurnal minimum). This could bring showers and
storms in a weakened state. Regardless, we'll have to keep an eye on
the potential severe threat for the later Tuesday into Wednesday
timeframe.
&&
.AVIATION /12Z TAFS THROUGH 18Z FRIDAY/...
Issued at 622 AM EDT Thu Apr 24 2025
VFR conditions are expected for the TAF period, but increasing mid-
level clouds will accompany rain chances for today. Isolated to
scattered showers and storms are most likely this afternoon, but
confidence on exact timing and placement is nearly impossible, so
PROB30 groups were utilized to highlight windows of best chances for
-SHRA or -TSRA. Some brief impacts to the terminals will be possible
if a TSRA moves over the airfield. Otherwise, look for winds to be
from the south today. VFR continues tonight, with additional rain
chances in the 30-hour extended forecast for SDF Friday morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
SHORT TERM...CJP
LONG TERM...BJS
AVIATION...CJP
Source:
LMK issues Area Forecast Discussion (AFD) at Apr 24, 6:24 AM EDT ...Updated Aviation Discussion...---------------
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