452
FXUS63 KIND 010705
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
305 AM EDT Wed Oct 1 2025

.KEY MESSAGES...

- Dry with unseasonably warm afternoons through early next week

- Drought is expected to persist and worsen across central Indiana
  into October

&&

.SHORT TERM (Today and tonight)...
Issued at 304 AM EDT Wed Oct 1 2025

There will be a similar synoptic scale set up for today with surface
high pressure to the northeast and broad scale subsidence across the
Ohio Valley. This will keep winds out of the NE with dry air
advection remaining over the region. Aloft, weak meridional flow
beneath the broader upper level ridge will aid in the increase of
upper level cirrus late today through tonight. This may dampen the
diurnal curve some, but overall conditions should remain rather
unchanged.

The NE flow along with steep lapse rates in the PBL should allow for
the near surface layer to dry out once again this afternoon. That
said, weaker flow in the 950-850mb layer will inhibit mixing some,
and we likely will not see the RH extremes we witnessed yesterday.
Still, went below guidance for afternoon with dewpoints in the
upper 40s. This will push afternoon RH values towards critical
fire weather thresholds, however winds at or below 10 kts should
keep the fire threat relatively low.

Overnight, another pocket of dry air will arrive from the northeast
essentially eliminating our succession of nightly nocturnal fog
development. This push of dry air may also allow for a few outlying
areas to fall into the upper 40s over NE central Indiana, however
there is some uncertainty due to the potential increase in upper
level cloud cover.

&&
High confidence in the long term forecast as a hot and dry weather
pattern continues for the region into early October. Surface high
pressure and ridging aloft will be the dominant weather influences
for Indiana`s weather in the next 7-14 days, keeping the summertime
heat locked in place with little to no chances for rain.

Little change in the day to day weather in the coming week as high
pressure slowly shifts from the Great Lakes to the Northeast to the
Mid Atlantic. A weakening moisture starved upper trough passes
overhead Wednesday and Thursday resulting in an increase in high
level clouds, but the only surface impacts will be slightly "cooler"
high temperatures in the lower 80s. Ample sunshine returns late week
into next weekend with highs reaching at least into the mid 80s..and
possibly upper 80s. Expect large diurnal temperature ranges in this
type of pattern with relief from the heat each night as lows drop
into the mid 50s to low 60s.

The main concern each day through next weekend are low afternoon RH
values dropping into the 15-30 percent range and the worsening
drought conditions. Model guidance struggles with drier air mixing
down to the surface and typically keeps dew points and RH too high
in patterns like this. Afternoon RH and Dew Points will likely be
closer to the NBM 5th percentile or lower each day. Watching the
possibility for an increased fire weather risk this week due to such
dry and hot conditions. Winds remain under any critical thresholds,
but the prolonged stretch of heat and dry weather may still lead to
an elevated fire weather risk.

High confidence exists in a weather pattern supportive of well above
normal temperatures and below normal rainfall continuing into Mid
October. Guidance struggles to break down these strong blocking
patterns in the long term, typically bringing in chances for rain
and storm systems too fast. While there are 20 PoPs around October
7th, this is a low confidence forecast that will likely change in
the coming days. While some longer range models and ensembles show a
few chances for rain by Mid October, low confidence exists in any
one solution. For now, keeping the extended forecast hot and dry.
.LONG TERM (Thursday through Tuesday)...
Issued at 304 AM EDT Wed Oct 1 2025

Dry and unseasonably warm pattern to continue over the Midwest into
early next week.  The long period period will begin with a staunch
subtropical H500 ridge centered over Indiana, while a corresponding
very broad area of surface high pressure centered over southern
Quebec occupies the eastern half of North America.  Weaknesses over
the northern Plains/Upper Midwest will lift into Canada while the
next noteworthy upper trough plunges through the western CONUS...
allowing the eastern upper ridge to expand northward over the
central US by this weekend.  These features will continue to shift
early next week, with the large surface high`s axis realigning along
eastern North America while the upper ridge suppresses slightly to
the southeast courtesy of strong low pressure crossing southern
Canada.

This will equate to rain-free conditions through next Monday under
an overall dry column...although southerly return flow around the
surface high positioning to our east may bring precipitable water up
to near 1.00 inch over the western Midwest at times into the
weekend.  Both dewpoints and early morning low temperatures will be
maintained in the 50s...with drying ground and ample sun promoting
more large diurnal spreads with afternoons effortlessly reaching the
80s.  Fire weather concerns should nevertheless be mitigated by
minimum RH values generally above 30 percent and markedly lighter
winds.

Better return of Gulf moisture starting on Sunday will be followed
by the Canadian system`s attempt to bring its cold front into
Indiana early next week...although the boundary may stall and slide
to our north around the massive stacked ridge.  However, these
features are expected to return higher dewpoints, clouds, and yes
probably a few rain showers by the end of the period.  So far low
confidence with chances and amounts of any rainfall next week with
these features possibly not combining over the CWA.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 1243 AM EDT Wed Oct 1 2025

Impacts:

- None

Discussion:

VFR cigs and vis are expected for the next 24-36+ hours at all sites
thanks to a broad surface high pressure ridge axis extending from
the Great Lakes into the MS valley. As the center of the surface
high continues to move east through the eastern Canadian provinces,
prevailing northeast winds will gradually become easterly. Wind
speeds will continue to follow a diurnal curve, increasing during
the day and diminishing at night. Similar to this afternoon, there
will likely be a brief period where wind gusts exceed 15 kts during
the mid-late afternoon hours /19-22z/ thanks to relative dry/deeply
mixed boundary layer. The only other sensible weather condition
worth noting will be gradually increasing scattered high clouds
spilling over the upper level ridge centered over the MS valley.

&&

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

$$

SHORT TERM...Updike
LONG TERM...AGM
AVIATION...Updike