660
FXUS63 KIND 091859
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
259 PM EDT Tue Sep 9 2025

.KEY MESSAGES...

- Gradually climbing temperatures through the week with near 90
  degree highs by Saturday

- Dry weather outside of low rain chances this weekend may lead to
  continued expansion of drought conditions into next week

- Dry fuels and low RH values each afternoon may lead to an elevated
  fire threat, but light winds should limit the overall threat

&&

.SHORT TERM (This evening through Wednesday)...
Issued at 252 PM EDT Tue Sep 9 2025

Quiet weather conditions are expected through the period as surface
ridging and a dry airmass remains in place. The center of the
surface high pressure has shifted well northeast of the Ohio Valley
which has allowed for winds to become more south or southeasterly.
This along with plentiful sunshine helped temperatures warm well
into the 70s today. Some locations could reach or briefly exceed the
80F mark over the next few hours. Deep mixing into an anomalously
dry airmass aloft is promoting low dewpoints in the 40s though,
making it feel comfortable.

A few upper waves moving through during the short term period will
provide an increase in mid-high clouds at times. Expect very dry air
in the lower levels to prevent any precipitation. High resolution
guidance was blended into the forecast for dewpoints during peak
heating as they more accurately simulate diurnal mixing. Low RH
values each afternoon and dry fuels supports an elevated fire
threat. The one caveat is winds remain light which should greatly
limit the threat for fires to spread. More details on this threat
can be found below in the fire weather discussion. Mostly sunny
skies on Wednesday will continue the warming trend. Look for highs
to reach the low-mid 80s.

&&

.LONG TERM (Wednesday night through Tuesday)...
Issued at 252 PM EDT Tue Sep 9 2025

Wednesday Night and Thursday...

Models suggest strong ridging in place aloft over the plains while a
quick moving short wave on the lee side of the ridge is expected to
push across Indiana on Wednesday Night. Best forcing looks to pass
during the evening hours. This system appears to be somewhat
moisture starved. Time heights show some low and mid level
saturation as a weak surface boundary passes, but subsidence remains
in play aloft and the majority of the column appears to remain dry.
Thus will expect some passing clouds on Wednesday Night into
Thursday as this wave passes. Overall, there appears to be a non-
zero chance for rain but confidence for any rain remains too low to
be significant.

Thursday Night through Tuesday...

A warm and dry pattern will continue across Central Indiana through
this time. The upper flow will remain highly amplified with the
previously mentioned strong upper ridge over the plains building
east to the Ohio Valley on Friday. This upper ridge is expected to
persist across Indiana through Tuesday, gradually shifting from
north-south orientation to a southwest-northeast orientation. The
impact of this will allow for a strong surface high to set up over
Quebec by Friday...shifting south to the east coast by late in the
weekend, warmer and more humid air will begin to arrive across
Central Indiana. Forecast soundings through the period suggest a dry
column, with convective temperatures in the upper 90s along with
minimal CAPE. Thus precipitation is not expected through the period
due to a lack of forcing and moisture. Thus partly cloudy days and
mostly clear nights along with above normal high temperatures will
expected. Look for high temperatures mainly in the middle to upper
80s through Monday.

As mentioned in earlier discussions, this dry weather may leading
more threatening fire weather and drought conditions in the weeks
ahead.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 117 PM EDT Tue Sep 9 2025

Impacts:

- None

Discussion:

VFR conditions are expected through the TAF period.

Some cirrus will pass through at times, and perhaps a few cumulus
may pop this afternoon. Winds will increase some and shift as the
day goes on to be more south or southeasterly at 10 kts or less.
Overnight winds should become light and more easterly again,
possibly calm at times. A weak upper wave moving in will keep mid-
high clouds around. Dry air should keep any fog at bay overnight.


&&

.FIRE WEATHER...
Issued at 259 PM EDT Tue Sep 9 2025

The lack of any significant rainfall over the last several weeks has
resulted in abnormally dry and minor drought conditions to develop
across Indiana. With little to no rain in the forecast for the next
7 days, confidence is increasing in an elevated fire weather threat
each afternoon as daily min RH values fall into the 20% range.
Lowered afternoon dew points each day through next Saturday to the
NBM10th percentile to account for such dry conditions and afternoon
mixing bringing down even drier air to the surface. The one factor
keeping the fire weather threat lower is the lack of wind. Despite
deep mixing, very weak low level flow should keep winds under 10 kts
through the period. It is worth noting that CPC has placed the
majority of the Midwest and Mid Mississippi Valley in a slight risk
for extreme heat for Sept 15-18th. If no appreciable rainfall is
observed this weekend, the fire weather threat may continue to
increase and persist into mid month. Will continue to monitor the
extended forecast for increasing fire weather concerns.

&&

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

$$

SHORT TERM...Melo
LONG TERM...Puma
AVIATION...Melo
FIRE WEATHER...Melo