textproduct: Indianapolis

KEY MESSAGES

- River and stream flooding continues across southern portions of Central Indiana.

- Cooler today with a brief break from rain chances, before showers and storms return to the forecast Friday into the holiday weekend, along with a return to warmer temperatures.

DISCUSSION (This evening through Thursday)

Issued at 303 PM EDT Thu May 21 2026

Current surface analysis depicts surface high pressure centered across the northern Great Lakes stretching down into parts of the Ohio Valley while a subtle wave moves across Ohio. Mostly cloudy skies have lingered primarily near the I-70 corridor and south due to weaker subsidence being further away from the surface high. Some breaks in the clouds are occurring though thanks to daytime heating despite the weaker subsidence. Look for quiet weather conditions to continue through tonight under the influence of surface high pressure to the north.

A more active pattern develops Friday through the weekend with multiple disturbances moving across the region. Model guidance depicts a mid-level shortwave and associated surface low lifting a warm front northward on Friday leading to increasing rain chances. Residual subsidence induced dry air will limit rain chances to mainly south-central IN Friday morning. Moisture surging northward should then allow for precipitation to overspread the northern half of central IN during the afternoon hours. Far northwestern counties may struggle to see more than a few hundredths of QPF due to the dry air. Weak instability may promote isolated embedded thunderstorms.

Sufficient moisture combined with forcing from the departing first impulse and another disturbance moving in Saturday will keep precipitation chances elevated. The highest precipitation chances on Saturday are focused across the eastern half of the CWA where the strongest forcing is expected. Instability appears to be weak again on Saturday, but isolated thunderstorms are possible.

Look for subtle ridging to build in late Saturday into Saturday night providing quiet weather before yet another shortwave moves in on Sunday. Sunday morning should start off mostly quiet as ridging shifts eastward. A shortwave and associated weak surface low will then move in Sunday afternoon supporting increasing precipitation chances. Model disagreement regarding the evolution of this relatively weak system leads to lower confidence in convective coverage during the afternoon hours. However, most guidance depicts modest forcing and moisture advection promoting scattered convection as the PBL heats up ahead of a weak frontal boundary.

An unsettled pattern is likely to continue through next week with daily chances for showers and storms. Long range guidance depicts multiple impulses aloft traversing the region while gulf moisture continues to gradually advect northward. Look for temperatures to moderate Friday through the weekend. Highs are expected to reach the low 80s by Sunday with highs in the 80s for much of next week.

AVIATION (00Z TAF Issuance)

Issued at 542 PM EDT Thu May 21 2026

Impacts:

- Mainly Low VFR Cigs overnight.

- MVFR ceilings likely developing Friday with showers aft 18-19Z.

Discussion:

GOES19 shows stratocu over IL, Western IN and southern Indiana. Easterly surface flow in place was trying to decay these clouds. However as cooling continues this evening, a warm front will begin to approach Central Indiana from the south. Forecast soundings and time heights keep mainly low VFR or MVFR cigs across the area overnight as this occurs.

Low pressure and an approaching cold front will push across Central Indiana on Friday. This will bring MVFR CIGS and rain showers to most of the TAF sites. HRRR remains on board with this, showing a shield of rain arriving on Friday afternoon before exiting late Friday evening.

IND WATCHES/WARNINGS/ADVISORIES

None.