215 
FXUS63 KIND 200135
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
935 PM EDT Fri Sep 19 2025

.KEY MESSAGES...

- Very warm temperatures persist into Saturday

- Chances for showers and a few thunderstorms arrive as early as 
  late tonight into Saturday

- Milder conditions Sunday onward with daily potential for showers 
  and storms next week

&&

.FORECAST UPDATE...
Issued at 935 PM EDT Fri Sep 19 2025

Only minor changes to the forecast with this update. First, added 
more weight to short-term high-resolution guidance to better capture 
the rapid post-sunset drop in temperatures that observations are 
showing. Second, trimmed back PoPs a bit since recent radar 
presentation has not been impressive and various CAMs are less 
enthusiastic about precipitation overnight. Kept at least slight 
PoPs across our western and northwestern counties, however, as weak 
large-scale forcing arrives overnight. Some shower/storm 
redevelopment is possible but should remain isolated in nature.

&&

.SHORT TERM (This evening through Saturday)...
Issued at 317 PM EDT Fri Sep 19 2025

The first rainfall chances in several days will move into the area 
later tonight as an upper level low that has been blocked to our 
west finally progresses eastward toward the region.

A few showers and perhaps a thunderstorm will be possible after 
about midnight tonight, and chances will linger into Saturday as the 
trough axis sits overhead and modest instability develops, though 
coverage and intensity should be limited. Better precipitation 
chances will hold off until the long term as moisture transport into 
the region will be fairly weak until at least early Sunday.

Low level temperatures and thicknesses suggest one more quite warm 
day on Saturday despite the increasing cloud cover and precipitation 
chances, with highs climbing into the mid to upper 80s across the 
area.

&&

.LONG TERM (Saturday night through Friday)...
Issued at 317 PM EDT Fri Sep 19 2025

A fairly dramatic pattern shift will continue into the long term as 
the blocking ridge that brought dry and hot weather this week will 
be replaced by two upper level waves that look to merge into a large 
closed low that will persist somewhere across the region into the 
eastern CONUS throughout much of next week.

This will lead to significantly milder temperatures and and an 
unsettled forecast with daily chances for showers and a few 
thunderstorms.

Model differences in the handling of this upper low do result in 
lower precipitation chances with time due to increasing uncertainty, 
but chances will be necessary most basically every period during the 
long term, with thunder probabilities largely diurnally driven.

Probability matched mean progs and model precipitable water values 
suggest a couple of periods, especially Sunday into Monday, when 
some more widespread showers will be possible, along with brief 
heavy downpours as PWAT values exceed climatological 90th 
percentile. Total rainfall through the period may be enough to put a 
dent in recently intensified drought conditions locally, though 
likely not quite enough to completely erase long term moisture 
deficits that now run as high as 5 or more inches in spots over the 
past 60-90 days.

Temperatures will be as much as 10 to 15 degrees cooler next week, 
depending upon the position of the low, as the exact position will 
determine degree of cloud cover and precipitation, which will 
significantly impact the resultant insolation.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 733 PM EDT Fri Sep 19 2025

Impacts: 

- Scattered showers and thunderstorms after 19z Saturday.

Discussion:

VFR conditions expected through tonight.

Clouds have increased over the past few hours and will continue to 
do so. Most terminals have a BKN to OVC deck at 25k ft. Expect 
ceilings to lower through the course of the night. A few showers are 
possible by LAF overnight as well.

Shower and eventually thunderstorm probabilities increase during the 
day on Saturday, especially after 19z. Most terminals will have a 
chance of seeing a storm, with the best probabilities (40 percent) 
near LAF...lower probabilities elsewhere.

Winds will remain light and variable tonight, becoming southerly 
during the day Saturday and remaining under 10kt.


&&

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

$$

UPDATE...Eckhoff
SHORT TERM...Nield
LONG TERM...Nield
AVIATION...Eckhoff