textproduct: Indianapolis

KEY MESSAGES

- Generally dry Thursday and Friday with isolated rain chances this afternoon. Thunderstorm chances Friday night, but confidence is low at this time.

- Near record warm temperatures expected through Saturday with multiple days in the 80s and lows in the 60s

- Much cooler Sunday into Monday with the potential for frost early Monday morning

DISCUSSION (This evening through Thursday)

Issued at 301 PM EDT Thu Apr 16 2026

Central Indiana is currently in the wake of a prior MCS with the parent surface low still to the NW. Remnant mid-level moisture is aiding in cu development as the atmosphere destabilizes, but there still is currently not enough forcing across central Indiana for these to grow into showers/storms. That said, there is a weak confluence boundary over NW Indiana that is allowing for isolated convection to occur, and a brief shower/storm cannot be ruled out through 22Z over NW central Indiana. Now that the cu-field is starting to expand, temperatures are likely to plateau, with the expected high only a few degrees above current temperatures.

Tonight, high pressure will move into the area, clearing skies and calming winds. This will lead to very efficient diurnal cooling with temperatures quickly dropping to near the expected dew point temperature and lows in the mid 50s. River valleys may drop even further, potentially into the upper 40s.

During the day on Friday, warm and dry air advection will arrive, pushing 850mb temperatures toward the 90th percentile of climatology. This will likely lead to temperatures slightly above guidance; highs are expected to be in the mid 80s. Upstream, prefrontal boundaries will ignite explosive convection across the mid to upper Mississippi Valley, of which should quickly grow upscale and develop strong cold pools. Model guidance is suggesting this will reach central Indiana between 06-09Z Saturday morning, but given the magnitude of the expected cold pools, these solutions may be slightly too slow. The earlier the MCS reaches central Indiana, the greater likelihood the cold pool will be strong enough to create damaging wind gusts for our area, and will be something to watch closely throughout tomorrow.

Due to the strong cold pool, there will be a corridor behind the aforementioned MCS and the frontal boundary, likely to be within central Indiana between 11-16Z. Within this corridor, modest mid level moisture, but weaker lapse rates should lead to sub-severe scattered showers and thunderstorms. Once frontal passage occurs, CAA induced pressure gains should lead to drying conditions and end the rain threat fairly quickly. The morning frontal passage will lead to a non-diurnal temperature curve with morning temperatures likely to be warmer than afternoon temperatures on Saturday.

Below normal temperatures will start off the new week in the wake of the exiting cold front and as a surface high slides south from Central Canada. Highs Sunday and Monday are expected to only reach the 50s to low 60s with the threat of frost early Monday morning.

Temperatures will quickly warm again for Tuesday and on as the Canadian high pushes east. Models also show the potential for a boundary setting up somewhere in the region by midweek, which could provide enough lift for some precipitation chances. For now keeping with the low PoPs during that time that guidance has provided as confidence in low in the long range solutions at this time.

Central Indiana will continue to often sit between systems with tight pressure gradients, so a few breezy days are expected for next week. Main concerns for now are Sunday, behind the exiting low, and Tuesday, ahead of the boundary setting up in the area. Both of these days could see gusts near 25-30 mph, mainly during the afternoon hours.

AVIATION (18Z TAF Issuance)

Issued at 109 PM EDT Thu Apr 16 2026

Impacts:

- Wind gusts to 25 kts this afternoon

Discussion:

VFR conditions are expected through the TAF period. Initially, broken to scattered cloud cover will remain, but high pressure building in from the west will lead to mostly clear skies by this evening. Mixing within the boundary layer has led to intermittent wind gusts between 20-25kt this afternoon. This should subside quickly near and after dusk with sustained winds dropping below 10kt by 01Z. Winds will calm overnight; periods of variable winds at 3- 4kt are possible, but predominantly winds should be below 3kt after 07Z. Winds will remain light and shift to out of the south tomorrow.

IND WATCHES/WARNINGS/ADVISORIES

None.