Georgetown, Indiana Weather Forecast Discussion

427
FXUS63 KLMK 211042
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
642 AM EDT Sun Sep 21 2025
...Updated Aviation Discussion and Forecast Update...
.KEY MESSAGES...
*  Rain chances increase today with scattered showers and
   thunderstorms expected in the afternoon. Some storms may become
   strong to severe, with gusty winds, brief heavy rainfall, and
   hail possible.
*  Another round of showers and storms are expected Monday afternoon
   and evening. These storms may also become strong to severe,
   bringing a chance for gusty winds, hail, and brief heavy rainfall.
*  Daily chances for showers and storms will last through next week.
   Beneficial rain ranging from 2" to 4" possible today through the
   end of next week. We will also see a return of normal
   temperatures next week.
&&
.UPDATE...
Issued at 641 AM EDT Sun Sep 21 2025
A cluster of showers and embedded thunder developed over the
Mississippi River and is moving ENE into central Kentucky this
morning. Increased PoPs slightly to account for the expanding
cluster of showers. Not expecting any strong storms with this
cluster, instead, it will likely begin to dissipate along I-65.
Another round of showers and storms will develop this afternoon,
which will bring few strong storms. High-res guidance is
initializing much better, so we are beginning to see model
convergence on timing for today.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 329 AM EDT Sun Sep 21 2025
Today...
A remnant outflow boundary is currently located along the Ohio
River, which has spawned a few isolated showers over southern
Indiana. The remainder of the region is dry and under mostly clear
skies.
Around sunrise, some high-res guidance brings some showers in from
the west. This is possible, though larger thinking is we will see
showers and storms develop to the west and approach central Kentucky
mid-to-late morning. Southerly/southwesterly flow will set up over
the region and help to usher in better moisture. We will see PWATs
around 1.6-1.7 inches in the afternoon. This moisture, coupled with
broad troughing just touching the region and a continuous stream of
vorticity, we will see scattered showers and storms push through the
region in the afternoon and into the evening hours. About 1500 J/kg
of SBCAPE, little to no capping, and modest low-level lapse rates
will help to promote a few stronger storms. Shear is weak, so not
expecting a lot of organized severe weather, but a few storms may
become severe. Main hazards are gusty winds, hail, and lightning.
Otherwise, looking to see temperatures in the mid-to-upper 80s for
highs and winds gusting up to 20-25mph in the afternoon.
Tonight...
The main trough axis will approach the region in the overnight
hours. Some vorticity shedding out ahead of the main trough, coupled
with a 25-30kt LLJ that overspreads the Ohio Valley will help to
promote isolated to scattered showers in the early morning over
southern Indiana and along the Ohio River. Due to elevated
instability, a few isolated storms will be possible. Temperatures
will be in the low-to-mid 60s, with some cooler spots in the upper
50s.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 329 AM EDT Sun Sep 21 2025
Monday - Tuesday...
The main trough axis will swing through the region on Monday
afternoon, bringing another round of showers and storms. SBCAPE will
be about 1300 J/kg in the afternoon, accompanied by 25-30kts of deep-
layer shear, ample moisture, and modest low-level lapse rates. We
could see some storms become strong to severe. Main threats would be
gusty winds, hail, and lightning. Best timing is late Monday
afternoon through the evening.
Monday night, upper flow remains with weak troughing, mid-level flow
becomes more zonal with continued vorticity streaming over the
region. A 25-30kt LLJ will overspread the lower Ohio Valley, which
will help to promote showers in the overnight. Elevated instability
and enough deep-layer shear will keep some storms overnight as well.
Mid and Upper level flow becomes more zonal on Tuesday, but
continued vorticity will stream overhead as it sheds from a closed
low over the high Plains. This vorticity and continued moisture will
bring another round of scattered showers and storms on Tuesday.
Wednesday - Next Weekend...
Troughing over the northeastern CONUS will slowly move off to the
northeast, which will drag the closed low over the high Plains
eastward and into the mid-Mississippi Valley closer to the end of
the work week. Wednesday and Thursday, continued vorticity and moist
air will keep scattered showers and storms in the forecast. By
Friday and into the weekend, we could see surface cyclogenesis from
the upper closed low. This will keep general troughiness over the
region through the weekend and chances for showers and storms will
remain. Otherwise, temperatures during this time look to be near
normal.
Rainfall Through The Week...
Over the last several days, the QPF forecast has increased each day.
Through the 7 days, we are looking at a widespread 2.5-3.5 inches of
rain, with totals around 4 inches in some areas. Given the
convective nature of this QPF forecast, locally higher and lower
amounts are possible. LREF probabilities of exceedance continue to
support this QPF forecast, with the probability of exceeding 3.0
inches around 30-40%.
&&
.AVIATION /12Z TAFS THROUGH 18Z MONDAY/...
Issued at 641 AM EDT Sun Sep 21 2025
A 25-30kt LLJ has developed over the lower Ohio Valley and has
developed a cluster of showers and embedded thunder over western
Kentucky. These showers have been expanding in coverage. At this
time, they will impact BWG, but have lower confidence on impacts at
other terminals.
By late morning/early afternoon, showers and storms will move into
the region from the west. These showers and storms will move through
the terminals between 17-00Z. Few storms could become strong to
severe. In the afternoon, winds will gust up to 20kts from the
southwest.
In the overnight, another LLJ will set up over the region and help
to keep isolated to scattered showers over the northern terminals in
the early morning hours.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
UPDATE...SRW
SHORT TERM...SRW
LONG TERM...SRW
AVIATION...SRW

NWS LMK Office Area Forecast Discussion