129
FXUS63 KIND 311854
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
254 PM EDT Sun Aug 31 2025

.KEY MESSAGES...

- Quiet and dry weather through Monday Night

- Below average temperatures to continue for much of the
upcoming week

- Next chance for rain arrives Tuesday and continues into early
Thursday followed by another round of cooler/drier air late week

&&

.SHORT TERM (This evening through Monday)...
Issued at 254 PM EDT Sun Aug 31 2025

Broad north-nw mid level flow on the backside of a longwave trough
centered over the eastern U.S will continue. At the surface, a
moderately strong 1025 mb high pressure will remain centered over
the Great Lakes with a ridge axis extending into east coast. Except
for some high clouds moving into the area from the west thanks to
weak upper level divergence, the weather will remain benign through
the period.

PWAT values will remain from 0.60 to 0.70 inch overnight (lowest
quartile of climo) sustaining mostly clear skies, except for the
occasional aforementioned high clouds. Another night of decent
radiational conditions will exist especially in the NE half of
Central Indiana where less high clouds are expected. Light winds and
dewpoints in the 40s will help temperatures to bottom out again from
the upper 40s to the lower 50s for the majority of Central Indiana.
The exceptions to this will be in portions of the Indianapolis
Metro, where the heat island effect will keep lows in the mid-upper
50s and in the coldest drainage locations of northern portions of
central Indiana which will have lows fall the mid 40s.

Although PWAT values will gradually increase tomorrow (up to 0.80
inch) as low level winds begin to advect slightly higher
dewpoints, forecast soundings suggest not enough moistening to
support any cumulus clouds during the afternoon. So other than high
clouds which are expected to gradually diminish through the day
as the upper divergence fields weaken and move SE, skies will be
mostly sunny. The airmass will continue to gradually warm, thanks to
large scale subsidence, however high temperatures are again expected
to be below normal (3-5 degrees) from the upper 70s to lower 80s.

&&

.LONG TERM (Monday night through Sunday)...
Issued at 252 PM EDT Sun Aug 31 2025

Cyclonic flow will dominate the eastern half of the country through
the period, producing continued below normal temperatures.

A modest closed low will spin to our east early in the week, as it
begins to weaken and gradually be absorbed into a much stronger and
larger closed low poised to drop into the region later in the week.
The forcing for ascent associated with this low will largely skirt
the area, keeping the early portion of the week dry, before some low
chances for showers and perhaps a storm sneak into the area as early
as late Tuesday.

More substantial rain chances will come Wednesday into early
Thursday as a much stronger upper low drops into the region out of
the Canadian prairies, bringing with it a substantial cold front and
a reinforcing shot of cooler air for late in the week, which may see
highs fail to get out of the 60s on Thursday and Friday for some
parts of central Indiana, and lows dropping well into the 40s if not
perhaps the upper 30s in spots.

The core of the coolest air with the upper low will only be briefly
in the region before retreating northward again, allowing some
moderation of temperatures to occur, though below normal
temperatures are likely to continue into next weekend and beyond.

Dry conditions will also return for the next weekend as surface high
pressure builds into the area post frontal passage.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 120 PM EDT Sun Aug 31 2025

Impacts:

- VFR conditions through the forecast period

Discussion:

Quiet for the terminals through the period. There will be an
increase in high clouds from the west over the next 12 hrs ahead of
broadly divergent area at 300mb over the mid MS/MO valleys. E-NE
winds will occasionally gust to near 12 kts this afternoon at KLAF
and KIND thanks to a deep mixed boundary layer and winds from 10-15
kts in the 2-5 kft layer. However, the only substantial impact for
these conditions will be some low level turbulence.

Winds will decrease and back 10-20 degrees in the evening owing to
diurnal tendencies. Overnight, ceilings will increase to scattered
in the north with a broken deck of cirrus expected later in the
night at KBMG and KHUF. By tomorrow morning the upper level
divergence fields tend to weaken and the cirrus deck is expected to
gradually diminish from the NW, while E-NE surface winds will
increase by late morning.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...Crosbie
LONG TERM...Melo
AVIATION...Crosbie