751
FXUS63 KIND 061336
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
936 AM EDT Mon Oct 6 2025

.KEY MESSAGES...

- Increasing clouds today with isolated to scattered showers,
  mainly across southern Indiana

- Widespread rain with some thunderstorms Monday night into
  Tuesday

- Dry and seasonable weather Wednesday through Friday, warmer into
  early next week

&&

.FORECAST UPDATE...
Issued at 934 AM EDT Mon Oct 6 2025

No major changes needed to the ongoing forecast but have brought up
the onset time for POPs across the southern counties as isentropic
lift is bringing isolated to scattered rain to the southeastern
portions of the forecast area. Total rain amounts so far have been
minimal as much of this lift is rooted in the mid-levels which
should be the case through much of the rest of the day today. Rain
coverage will increase towards the late afternoon and early evening
as the LLJ gradually begins to ramp up, but continue to expect to
see the heaviest rain during the overnight hours into Tuesday.

Temperatures will be highly variable across the forecast area with
more thick cloud cover across the southern counties keeping
temperatures in the upper 70s while areas to the northwest which
should see little to no clouds for much of the day will rise into
the low to mid 80s.

&&

.SHORT TERM (Today and tonight)...
Issued at 302 AM EDT Mon Oct 6 2025

Surface analysis early this morning shows strong high pressure in
place over the middle Atlantic States, extending east into the
Atlantic. This broad high continued to influence the weather across
Indiana, providing warm but light southerly winds, subsidence and
clear skies. A cold front was found stretching from eastern WI,
across IA to eastern KS.  Water Vapor imagery shows subsidence in
place across Central Indiana with southwest flow in place aloft. An
area of moisture was found near the previously mentioned cold
frontal boundary, and additional moisture was found over the deep
south and gulf coast. Dew points remained quite moist, in the upper
50s and lower 60s.

Today...

A changeable weather day is in store today. The day will begin
similarly to how the past few days have, sunny and warm. However, by
the end of day clouds will have invaded along with scattered to
isolated showers, with more widespread rain tonight.

Two weather features will be approaching Central Indiana today.
Models show moisture and forcing advecting northward from the deep
south, amid the southwest flow aloft and southerly surface flow.
Additional moisture and forcing will approach from the northwest,
associated with an approaching upper trough and its previously
mentioned cold front. As these features come together today,
forecast soundings show gradual saturation, with deep saturation
achieved by late afternoon and early evening. Pwats have consistently
shown favorable moisture with values near 1.7 inches. HRRR shows
scattered shower development arriving in Central Indiana from the
south this afternoon...associated with the mid level moisture
advection from the deep south. Coverage should become more
widespread toward 00Z. Confidence is high for rain late today and
tonight.

Thus will start out with dry pops today and begin ramping pops
upward from south to north through the afternoon hours. Cloud cover
will also have a similar trend. Given the warm start to the day and
plentiful morning sunshine,  highs at or just below persistence, in
the lower 80s will be expected.

Tonight...

Confidence for rain tonight is quite high as all the previously
mentioned rain making ingredients are suggested to converge over
Indiana. Again, these ingredients being the moisture surge from the
south and the approaching upper trough and cold front. Forecast
soundings through the overnight hours remain saturation from nearly
00Z-09Z as these feature arrive. Again pwats show plentiful moisture
with values near 1.6 inches.  Some top down subsidence appears to
arrive after 09Z as the upper trough pushes some of its moisture and
forcing farther east. Still, plenty of saturation appears to remain
within the mid and lower levels. Thus will continue with very high
pops this evening and overnight, ever so slightly backing off after
09Z as some subsidence arrives.

&&

.LONG TERM (Tuesday through Sunday)...
Issued at 302 AM EDT Mon Oct 6 2025

A brief break in the abnormally dry conditions expected on Tuesday
as a frontal system brings widespread rain and a few storms to
Central and South Central Indiana. More seasonable October weather
arrives midweek with a warming trend back to the 70s for next
weekend. Watching for the possibility of patchy frost in North
Central Indiana and Wabash River Valley late Wednesday and Thursday
night.

A frontal boundary pushes through the state Tuesday bringing rain
and thunderstorms to much of Central and South Central Indiana. The
heaviest rain is expected across southern Indiana during the early
morning hours as a surge of Gulf air moves northward associated with
a strengthening low level jet aloft. Forcing from the surface front
lags behind the stronger lift associated with the LLJ, keeping
precipitation chances into the daytime hours on Tuesday as the front
passes through. Not expecting a complete washout of a day for
Central and North Central Indiana as precipitation is expected to be
more scattered in nature, ending from NW to SE in the afternoon.
Most widespread rain and storms should be south of the I-70
corridor, shifting toward the Ohio River through the day. The
heaviest rain will be confined to the southern portions of the
state, but expect much of the area to see amounts of 0.5 to 1.0
inches with some locally higher amounts of around 1.5 inches. A
sharp QPE gradient likely will exist north of I-70, with amounts
diminishing further north.

Much cooler weather will move in behind the frontal passage with the
potential for lows in the upper 30s and low 40s Wednesday and
Thursday night and highs in the upper 60s to low 70s through Friday.
Surface high pressure will dominate the weather pattern through the
second half of the week with dry weather expected. Coolest night
should be Thursday night as lighter winds and clear skies make for
better radiational cooling. Patchy frost may occur outside of urban
areas in Central and North Central Indiana by Friday morning.

Next Weekend...

A similar pattern will persist Friday into the weekend with a broad
and weak upper low across the Eastern US and surface high pressure
being the dominant weather influence locally. Long term guidance has
been consistent in showing a gradual warming trend back to the 70s
by the weekend as the cooler Canadian airmass shifts east and
southerly flow brings a warmer airmass northward. Despite a warning
trend, temperatures do not look as anomalously warm as things have
been to start the month. The pattern continues to favor drier than
normal conditions with little to no signs for additional appreciable
rainfall.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 656 AM EDT Mon Oct 6 2025

Impacts:

- Deterioration to MVFR conditions late this afternoon and tonight.
- Scattered showers developing this afternoon, continuing Tonight

Discussion:

Satellite imagery shows clear skies across Central Indiana early
this morning. Mid and upper level moisture over the south will
continue to surge northward leading to an increase in mid and upper
level clouds through the day. While VFR cigs and vis should prevail
through the rest of the day, expect scattered showers to begin
developing from south to north later this afternoon and evening.
Conditions then deteriorate overnight tonight into tomorrow morning
as rain and a few storms become more widespread, especially south of
I-70. Have all sites with MVFR conditions overnight, but possibility
is there for periods of IFR cigs and vis under heavier showers and
storms.

Winds remain southerly through the period increasing to around 10
kts this afternoon.


&&

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

$$

UPDATE...White
SHORT TERM...Puma
LONG TERM...CM
AVIATION...CM