Jasper, Indiana Weather Forecast Discussion

549
FXUS63 KLMK 202028
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
428 PM EDT Sat Sep 20 2025
.KEY MESSAGES...
*  Mainly dry and unseasonably warm today with highs in the upper
   80s and low 90s. Very isolated showers and storms possible
   through this evening.
*  Rain chances increase during the day Sunday with scattered
   showers and thunderstorms. Some storms may become strong, with
   gusty winds, brief heavy rainfall, and hail.
*  Daily rain chances through next week. Beneficial rain ranging
   from 2" to 4" possible tonight through next Friday night.
&&
.SHORT TERM /THROUGH SUNDAY/...
Issued at 428 PM EDT Sat Sep 20 2025
The lead upper level shortwave trough is lifting northeast over the
Midwest and Ohio Valley this afternoon, which has helped initiate
scattered strong convection across portions of MO/IL in a more
favorable thermodynamic environment. Locally, activity has been weak
and very isolated thus far, as expected. Moisture advection into the
region has been pretty weak up to this point, but shorter range/hi-
res models continue to point to richer low-level moisture (and
higher PoPs) on Sunday. However, very spotty showers and even a
storm or two will remain possible through the evening hours.
Temperatures are topping out in the upper 80s and lower 90s.
The lead upper level trough continues to lift northeast of the
region tonight into Sunday, while a subtle mid-level disturbance
follows quickly on its heels. A modest 25 kt SW LLJ develops over
the Ozarks tonight before streaming northeast across the Lower Ohio
Valley on Sunday. The low-level jet noses into western KY by 12Z
Sunday and could help spark isolated to scattered showers in south-
central and west-central KY as early as 10-13Z. Otherwise,
rain/thunderstorm chances will gradually increase into the 30-50%
range area-wide from late morning through mid-afternoon as the lower
levels warm and moisten.
Destabilization will be modest, as sfc heating will be limited
somewhat by mid and upper sky cover. Around 1000+ J/kg MLCAPE will
be possible during the afternoon hours when showers/storms are
expected to increase in coverage. Effective deep shear is pretty
weak, only up to 15-20 kts. Storm mode looks like a combo of single
cells and multicells, with only loose organization. A few stronger
storms will be possible, which could produce brief heavy rainfall,
locally gusty winds, and lightning. Afternoon highs in the mid/upper
80s will be common, with a few sites approaching 90 in the Bluegrass
if the clouds hold off long enough.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Issued at 428 PM EDT Sat Sep 20 2025
Sunday Night - Tuesday...
Isolated to scattered showers and elevated storms will remain
possible Sunday night in a moist environment. Another upper level
shortwave trough upstream is forecast to swing east from the central
Plains over the Mid MS Valley. This wave will approach and move
across central KY and southern IN Monday and Monday night. This will
keep a wetter, unsettled pattern in place into next week. Lows
Sunday night will be in the low to mid 60s.
Forecast soundings continue to show modest CAPE and quite a bit of
moisture/cloud cover on Monday. Showers and storms are likely, and
some strong storms are possible. Highs will reach the low to mid
80s.
On Tuesday, upper flow becomes messy and mostly zonal with a
continued vorticity stream from a developing cut-off low over the
High Plains. Scattered showers and storms will be possible on
Tuesday.
Wednesday - Friday...
Medium range guidance continues to point to the idea of a deepening,
closed upper low slowly traversing the central CONUS during the mid
to late week time frame. The upper low could perhaps reach the Ohio
Valley by Friday or Friday night toward the the end of the forecast
period. Some degree of sfc cyclogenesis looks possible over the
Lower Ohio Valley ahead of the upper low during this time frame. The
end result looks like a pretty wet pattern, and as a whole, the
upcoming week looks like the drought-busting weather pattern that
many are hoping for. Total 7-day QPF of 2-4 inches of rain is
expected across the region, and locally higher amounts will be
possible due to convection.
&&
.AVIATION /18Z TAFS THROUGH 00Z MONDAY/...
Issued at 155 PM EDT Sat Sep 20 2025
Winds are light and somewhat variable this afternoon, but prevailing
winds will be out of the SSE around 4-7 kts between 18-00Z. VFR
conditions are likely with SCT clouds at 7-9 kft this afternoon and
SCT high cirrus streaming in from the west. High clouds will thicken
somewhat later this evening and overnight.
Mainly dry conditions continue this afternoon and evening, though
there is a 10% chance for an isolated shower/storm. For example, an
isolated small shower will begin the period near RGA. There is also
a low chance for isolated precip overnight, but the higher
rain/storm chances will be on Sunday (especially in the
afternoon/evening).
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Air Quality Alert until midnight EDT tonight for KYZ029>031.
IN...Air Quality Alert until midnight EDT tonight for INZ077>079-
     090>092.
&&
$$
SHORT TERM...EBW
LONG TERM...EBW
AVIATION...EBW

NWS LMK Office Area Forecast Discussion