Cottagegrove, Indiana Weather Forecast Discussion

921
FXUS61 KILN 231425
AFDILN
Area Forecast Discussion
National Weather Service Wilmington OH
1025 AM EDT Tue Sep 23 2025
.SYNOPSIS...
Periods of showers and thunderstorms are expected through midweek,
with daily chances for rain lingering through the remainder of the
workweek. Drier conditions are favored this weekend into early next
week. Near normal temperatures will prevail through the week, with a
gradual warmup late weekend into early next week once again.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Updated to remove the dense fog advisory for this morning as
visibilities have improved.
Although the bulk of the SHRA/TSRA activity has
departed, a trailing boundary back to the SW across the srn third of
the local area is providing a focus for renewed ISO/SCT activity
(primarily near/SE of I-71). S/W energy is still lingering back to
the W of the local area in srn IN and the maintenance of better jet
energy across the srn part of the region should be enough to keep at
least SCT activity going across the Tri-State/SW OH into s-central OH
and N/NE KY for several more hours before decreasing in coverage
toward daybreak into mid- morning. With above normal PWs and
relatively weak steering- layer flow, additional isolated heavy
downpours will be possible through sunrise across the SE third of the
ILN FA.
A narrow WSW-to-ENE axis of ISO convection will be maintained from
N/NE KY through south-central OH through the daytime. However, today
is looking drier than was the case yesterday, even with ISO/SCT
activity across the E/SE quarter of the local area at times through
early evening.
Temps bottom out in the lower to mid 60s by sunrise before
rebounding to the upper 70s to around 80 by late this afternoon.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Midlevel flow will become zonal late today through tonight as a
positively-tilted longwave trof pivots SE from the Great Lakes
through the south-central plains. S/W energy embedded within this
zonal flow will translate E into the OH Vly tonight through
Wednesday, promoting a reintroduction of widespread SHRA/TSRA into
the fcst locally, particularly by daybreak (and beyond) Wednesday.
Large-scale forcing and ascent will be on the increase late tonight
as better jet dynamics again overspread a sufficiently-saturated
profile. An enhanced LLJ will pivot to the NE into the srn OH Vly,
promoting a focused corridor of mass/moisture convergence into the
srn half of the local area late tonight. This will allow for heavier
pockets of SHRA/TSRA to develop/overspread near/S of the OH Rvr for
the latter part of the overnight through late morning Wednesday, with
continued SCT activity expected through the daytime as the
broad/deep trough trudges eastward through the region.
The combination of large-scale ascent amidst PWs >150% of seasonal
norms suggest that pockets of heavy rain will again be possible late
tonight through Wednesday, with the best chance for an additional
inch+ of rain through the short term period likely to focus near/S
of I-70 and especially near/S of the OH Rvr.
Temps tonight dip into the low/mid 60s before rebounding into the
mid/upper 70s Wednesday amidst expansive cloud cover and several
bands of SHRA/TSRA pivoting through the region.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
PVA continues to pivot through the Ohio Valley Wednesday night. As
this upper level energy interacts with a humid air mass, widespread
showers and a few thunderstorms can be expected Wednesday night.
Hydro concerns should be very limited, but any locations that
receive training thunderstorms could have some localized flooding.
The orientation of the H5 trough becomes modified on Thursday,
remaining positively tilted but far less steep compared to previous
days. This will aid in the eastward propagation of the trough, which
will influence how long PoPs remain in the forecast. Dry air
advection will begin to occur late Thursday into Friday as a
northwesterly flow regime develops. Coverage in rain will gradually
decrease throughout the day on Thursday, with rain chances becoming
far less likely on Friday (although a stray shower still cannot be
ruled out).
Global models still showing differences in how the synoptic pattern
resolves this upcoming weekend. More than likely, dry conditions
return for our CWA, with temperatures trending just above seasonal
normals. A cut off low may develop in portions of the southeastern
CONUS, which if this occurs, will have to monitor exact placement of
this low. A subtle northward shift could modify the forecast in our
southern counties.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
Several ISO pockets of SHRA continue to progress to the NE along a
boundary focused from near KCVG/KLUK to KILN to just S of KCMH/KLCK.
Activity should remain spotty in nature, with any potential impacts
of reduced VSBY due to SHRA (favored at KCVG/KLUK) being brief. In
fact, this narrow axis of ISO activity may remain fairly persistent
through the daytime, but the bulk of coverage should be just S of the
terminals during this time, with dry conditions favored at the local
sites.
The main item of interest for the TAF period is going to be the
timing of the lifting/scattering of IFR/LIFR CIGs and improvements
of MVFR/IFR VSBY to VFR through this morning into early afternoon.
VSBY should return to VFR area-wide by 15z, with MVFR/VFR Cu slowly
scattering out between 18z-21z. Thickening mid/high clouds will
overspread the region once again past 00z, with a reintroduction of
widespread SHRA with embedded ISO TS once again from SW to NE after
06z Wednesday, with greatest coverage likely to evolve toward 12z and
beyond. VFR CIGs will trend back to MVFR toward daybreak Wednesday.
OUTLOOK...MVFR/IFR CIGs are possible Wednesday through Thursday
night, with MVFR VSBY also possible. Thunderstorms are possible
Wednesday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...KC
NEAR TERM...
SHORT TERM...KC
LONG TERM...Clark
AVIATION...KC

NWS ILN Office Area Forecast Discussion