textproduct: Indianapolis

KEY MESSAGES

- Showers and thunderstorms likely tonight into Sunday with a marginal risk of severe weather.

- Much cooler temperatures Sunday night through Monday night with highs in the low to mid 70s and lows in the 50s.

- Tuesday-Thursday: overall seasonable warmth/humidity...with potential for multiple rounds of unsettled weather.

DISCUSSION (This evening through Saturday)

Issued at 326 PM EDT Sat Jun 13 2026

Rest of Today...

Several MCV's over IL will shift eastward into IN late this afternoon. Mesoanalysis a narrow axis of SBCAPE from 1500-2000 J/KG associated with return moisture (dewpoints in the mid to upper 60s) across eastern IL. A few thunderstorms currently over IL associated with the lead zone of WAA may make it into western IN before weakening. Have carried showers with chances TS across western zones this afternoon to account for this activity. There is a narrow zone of stronger flow and potential for strong to marginally severe TS in far SW zones. However in this area recent satellite and radar imagery shows extensive cloud cover and light elevated showers, so threat appears to be fairly marginal.

Thunderstorms over the Central Plains forming along a cold front will shift eastward towards central Indiana. Forecast soundings show little in the way of instability (MUCAPE less than 1000 J/KG). As a result, convection is expected to be primarily showers with some widely scattered thunderstorms. Marginal instability should limit any severe threat, despite all of central Indiana remaining in a marginal risk overnight.

Tonight....

Thunderstorms over the Central Plains forming along a cold front will shift eastward towards central Indiana. Forecast soundings show little in the way of instabilty (MUCAPE less than 1000 J/KG). As a result, convection is expected to be primarily showers with some widely scattered thunderstorms. Marginal instability should limit any severe threat, despite all of central Indiana remaining in a marginal risk overnight.

Sunday....

Surface front will push through central Indiana during the late morning and Tonight into mid-afternoon period. Copious amounts of clouds and light precip to start the day with remnants of overnight convection will limit destabilization. There does appear some sweet spot with convective redevelopment potential in SE zones. Some of the RRFS cam guidance has showed this area as a region of strong convection between 18-20Z. Day 2 SPC outlook keeps IN out of any severe risk, but given the aforementioned potential, there does appear to be some severe risk, albeit marginal. In the wake of the cold front, temperatures and humidity will slowly fall.

Sunday Night through Monday Night...

In the wake of a cold front, pleasant late Spring weather will move into the region associated with high pressure. Highs in the 70-75 F range and lows in the 50s will be 5-10 degrees below normal.

Tuesday through Saturday...

Late spring upper-level cut-off low will continue to spin near northern Ontario, promoting a broad zonal trough off lowered heights across the CONUS' north-central quadrant. Indiana should be a battle ground of sorts with corresponding warm/stationary frontal boundary established near Midwest...focusing gradient between strong deep moisture near Ohio Valley and any short wave energy sliding eastward within the zonal flow. Lower confidence in conditions for any particular 12-hr period, yet potential certainly exists for at least occasional moderate to very heavy rainfall, at least scattered severe weather, and flash flooding.

Tuesday will begin the transition back to a more active pattern, albeit still pleasant for mid-June with only upper 70s and 50s dewpoints expected...ahead of a wave from the northwest that will bring likely showers and possible thunder, especially into Tuesday night. Peak storm/severe potential to follow Wednesday into early Thursday as strengthening low pressure to our west increases frontal gradient near the area and pumps precipitable water aloft to 1.50 to 2.20 inches. Lower certainty on how upper forcing will swing over the local area, but heavy rain / flash flooding and at least isolated strong/severe winds are on the table...with potential for greater coverage of severe storms if mid-level vort better targets central Indiana.

Canadian cut-off should shift its lobed structure going into late work week...pushing the mid-week system to the Northeast, allowing at least modest surface high pressure to descend across much of the eastern two-thirds of the US. A return to at least a couple periods of WNW flow should bring more reasonable warmth/lower humidity to end the forecast period.

AVIATION (18Z TAF Issuance)

Issued at 141 PM EDT Sat Jun 13 2026

Impacts:

- Low chance for -SHRA/isolated TSRA late this afternoon - SHRA/TSRA increase in coverage after 06Z Sunday - MVFR ceilings likely after 06Z Sunday, IFR possible by 12Z - Wind shift to northwesterly within 10Z-16Z Sunday

Discussion:

VFR conditions are expected near central Indiana terminals today, with low chances of -SHRA after 21Z through this evening amid approaching mid-level system/cold front. Convective chances increase late tonight...as corresponding low-level moisture advection will promote ceilings deteriorating to MVFR around 08Z-10Z...with brief IFR possible at KBMG/KIND. Expect improvement Sunday morning...first as -SHRA taper off from west to east...and then as stratus lifts to VFR from KLAF to KBMG around 15Z-19Z.

SSW/SW winds slightly increasing within a 5-12KT range this afternoon will include a few gusts up to 15-20KT...before diminishing slightly after 00Z, to under 7KT at all terminals except KIND. Cold frontal passage Sunday morning will veer winds to NW, quickly at KLAF around 11Z...and more gradually at KBMG during 12Z- 18Z.

IND WATCHES/WARNINGS/ADVISORIES

None.