999 FXUS63 KIND 221506 AFDINDArea Forecast Discussion National Weather Service Indianapolis IN 1106 AM EDT Mon Sep 22 2025
.KEY MESSAGES...
- Showers and some thunderstorms will move through the area today, with highest chances of moderate to heavy rainfall rates over southern portions of the area.
- Milder with daily chances for showers and a few thunderstorms through much of the work week.
&&
.FORECAST UPDATE... Issued at 1106 AM EDT Mon Sep 22 2025
Radar imagery as of 11am is showing a large area of stratiform rain with embedded convective elements over the southern half of our CWA. Further north, generally north of a line from Terre Haute to Kokomo, dry conditions persist. Precipitation is moving to the northeast and has gradually been intensifying. Of note is an apparent mesoscale circulation just west of Vincennes. Convection has been most intense near this feature with heavier rainfall rates. Little in the way of lightning is noted, however. Given the current setup, the heaviest rain is expected to remain south of the Terre Haute to Kokomo line, with the most intense rates across our southern counties ... associated with the mesoscale circulation. We lowered high temperatures due to the ongoing steady rainfall which will persist into the afternoon hours. The bulk of the rain should exit our area later in the afternoon, leaving us with a dry overnight. Abundant rainfall today may allow for increased fog potential tonight.
&&
.SHORT TERM (Today and tonight)... Issued at 300 AM EDT Mon Sep 22 2025
An upper level trough will bring rain to much of central Indiana today, with rain chances lingering into tonight.
Early this morning, radar shows some light rain across eastern Illinois and western Indiana associated with some upper energy ahead of the main trough. Meanwhile, showers and thunderstorms were across Missouri and southern Illinois, associated with an MCV and the main energy in the upper trough.
As the upper trough moves east, forcing and moisture will continue to move northeast into central Indiana this morning. Showers and some thunderstorms will overspread much of the area, so will go with likely or higher PoPs most areas at some point during the morning.
Another shot of forcing with the upper trough will impact mainly the southeastern half of the area this afternoon. Increasing 850mb winds (30-35kt) will aid in this forcing as well as keep the flow of moisture into the area. Will continue high PoPs this afternoon across the southeast half, with lower PoPs to the northwest.
HREF Probability Matched Mean QPF shows the potential for localized 2 inch amounts in the far south through today, and this looks reasonable given the amount of moisture available and the increasing 850mb winds this afternoon.
Instability doesn`t look impressive today given the expected rain and cloud cover, so feel odds of any severe storms remain low even with the increased wind fields this afternoon. If breaks in the clouds appear and instability builds, an isolated strong storm couldn`t be ruled out in the south.
Clouds and rain will keep highs in the 70s today.
Forcing will diminish from northwest to southeast tonight, allowing PoPs to diminish during the night. Light winds and a moist boundary layer could lead to some patchy fog, especially if breaks in the cloud cover appear. Will add a mention overnight. Lows will be in the 60s.
&&
.LONG TERM (Tuesday through Sunday)... Issued at 300 AM EDT Mon Sep 22 2025
A much different week is expected this week than last, with near constant chances for showers and a few thunderstorms, and significantly milder temperatures.
A large closed low will gradually drop into the region this week, bringing relatively widespread cloud cover, near constant rain chances (particularly during the work week) and significantly milder temperatures.
Differences in placement and movement of the upper low with time result in greater uncertainty and thus lower rain chances later in the week, but suffice to say rain chances will be present basically every period through at least Saturday. Total rainfall through the week may be enough to put a substantial dent in longer term rainfall deficits, though perhaps not enough to erase them completely. Dry weather looks to return during the weekend into next week as the upper level disturbances depart.
Temperatures will be substantially cooler this week, particularly mid to late week, as a result of the closed low and associated cloud cover/precipitation, with max/min temperatures much nearer climatological normals in the mid 50s and mid 70s.
&&
.AVIATION (12Z TAF Issuance)... Issued at 645 AM EDT Mon Sep 22 2025
Impacts:
- MVFR/IFR conditions expected throughout much of the period - Showers and some thunderstorms at times today
Discussion:
Showers and some thunderstorms will continue to overspread the sites this morning, with MVFR conditions developing. Widespread showers will diminish from the north and west this afternoon, with predominant MVFR/IFR ceilings becoming widespread (KLAF may be an exception).
Overnight tonight, conditions will deteriorate in stratus and fog, with IFR ceilings and MVFR visibility likely. Visibility may become IFR as well, but will see how things develop before putting that in.
&&
.IND WATCHES/WARNINGS/ADVISORIES... None. &&
$$
UPDATE...Eckhoff SHORT TERM...50 LONG TERM...Nield AVIATION...50
NWS IND Office Area Forecast Discussion