Bloomington, Indiana Weather Forecast Discussion

617
FXUS63 KIND 210707
AFDIND
Area Forecast Discussion
National Weather Service Indianapolis IN
307 AM EDT Sun Sep 21 2025
.KEY MESSAGES...
- Scattered showers and thunderstorms today becoming numerous tonight
- Isolated severe storms with damaging winds possible this afternoon
  into early evening
- Milder with daily chances for showers and a few t-storms next week
&&
.SHORT TERM (Today and tonight)...
Issued at 306 AM EDT Sun Sep 21 2025
Central Indiana will remain under the influence of a large upper
trough throughout the short term period. This will keep chances for
showers and thunderstorms around.
Early This Morning...
An initial piece of upper energy is aiding scattered to numerous
showers and a few thunderstorms moving northeast across the area
this morning. These will continue to move northeast through the
predawn hours and could bring some brief heavy rain to parts of the
area.
Additional convection across western Kentucky is weakening, but will
have to watch to see if any holds together to reach the southwest
forecast area before 12Z.
Will generally have up to likely PoPs across the area to cover the
above.
Today...
Will keep some lower PoPs around this morning in case weak forcing
manages to spark some convection, but higher coverage of convection
should occur this afternoon as additional weak forcing moves in
during the peak of instability.
The weak forcing should keep coverage below the numerous (likely)
category. Instability is decent but shear looks weak. Low level
lapse rates will steepen up this afternoon. Soundings show dry low
levels, and this has the potential to enhance downdrafts. Thus, feel
an isolated severe storm with damaging winds is possible this
afternoon.
Thanks to increased cloud cover, highs today will be a little cooler
than previous days, with readings in the lower and middle 80s
expected.
Tonight...
The afternoon`s convection may linger into the early evening before
weakening/moving east of the area.
Forcing will ramp up overnight as an upper level jet moves to the
northwest of the area, and upper heights fall as the upper trough
moves closer. Moisture will be plentiful, with southwest winds
bringing a flow of moisture into the area through the night.
Loss of heating will lower the lapse rates and should keep the
isolated severe storm threat confined to early evening.
With the expected forcing and moisture, will go with likely category
or higher PoPs most areas overnight.
Clouds/rain will keep temperatures in the 60s for lows.
&&
.LONG TERM (Monday through Saturday)...
Issued at 306 AM EDT Sun Sep 21 2025
A much different week is expected this week than last, with near
constant chances for showers and a few thunderstorms, and
significantly milder temperatures.
Early in the week, a frontal zone will gradually sink into the
region as multiple upper level disturbances move through the area,
while a large upper closed low gradually develops and persists
somewhere in the eastern half of the CONUS later in the week and
into the weekend.
Differences in placement and movement of the upper low with time
result in greater uncertainty and thus lower rain chances later in
the week, but suffice to say rain chances will be present basically
every period through at least Saturday. Total rainfall through the
week may be enough to put a substantial dent in longer term rainfall
deficits, though perhaps not enough to erase them completely.
Temperatures will be substantially cooler this week, particularly
mid to late week, as a result of the closed low and associated cloud
cover/precipitation, with max/min temperatures much nearer
climatological normals in the mid 50s and mid 70s.
&&
.AVIATION (06Z TAF Issuance)...
Issued at 1252 AM EDT Sun Sep 21 2025
Impacts:
- Scattered convection continues at times through the day
- More numerous showers and some storms tonight
Discussion:
Outside of convection, VFR conditions are expected through 06Z
Monday.
Showers and a few thunderstorms are possible during the entire
period as rounds of forcing move through, but confidence in specific
timing is low. Will use generic VCSH, and then use PROB30s to
indicate times when coverage should be higher.
One round of more coverage is expected in the predawn hours, with
another round probably developing this afternoon. More widespread
showers will move in tonight.
Drier low levels will keep ceilings outside of convection VFR
through 06Z Monday. Winds may vary with boundaries from convection.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...50
LONG TERM...Nield
AVIATION...50

NWS IND Office Area Forecast Discussion