textproduct: Indianapolis

KEY MESSAGES

- Quiet pattern continues through Wednesday amid light winds and near normal temperatures, patchy fog tonight in rural areas

- Rain and storm chances return Wednesday night and persist through early next week, greatest chances Thursday and Friday

- Localized flooding will be possible at times from repeated rounds of convection

- The setup this weekend into early next week could support a few strong to severe storms, confidence on exact details remains low

DISCUSSION (This evening through Tuesday)

Issued at 300 PM EDT Tue Aug 4 2026

Today through Wednesday...

Expect mostly quiet weather conditions with surface high pressure pushing east across the region. Diurnal cumulus has developed across much of central Indiana as convective temperatures have been reached. The greatest coverage is across western portions of central Indiana where there is slightly deeper moisture present. Look for the diurnal cumulus to dissipate during the evening hours. Mostly clear skies and very light winds could promote additional patchy fog development late tonight. Drying soils the past few afternoons will keep coverage more limited, but cannot rule out fog in rural areas or near rivers. Any fog that develops will mix out in typical diurnal fashion Wednesday morning.

Expect surface high pressure to continue shifting east on Wednesday while a shortwave aloft and associated weak surface low approach very late in the day. Residual subsidence induced dry air will keep weather conditions dry through the day, but a stray light shower appears possible near far northwestern counties during the evening. Expect temperatures to gradually warm thanks to modest warm air advection. Highs are generally going to be near normal.

Wednesday night through early next week...

Guidance depicts a longwave trough across the north-central CONUS during the remainder of the forecast period with multiple embedded shortwaves traversing the region. These impulses will promote additional convective chances at times as deeper moisture surges back into central Indiana. The greatest precipitation chances are on Thursday and Friday when the strongest forcing overlaps with the deeper moisture surging northward. A frontal boundary associated with a weak disturbance will likely stall near the region by Thursday. Additional shortwaves tracking along the boundary supports daily precipitation chances through early next week.

Some guidance suggest low amplitude upper ridging builds in Sunday into Monday with an EML advecting towards the region. This leads to lower confidence in convective coverage and precipitation chances both days. Varying model solutions also results in higher uncertainty regarding specific details on timing or evolution of each subsequent shortwave pushing into central Indiana.

In general, models depict strong destabilization most days and enhancement of mid-upper level flow from the passing waves. This could potentially support isolated severe thunderstorms somewhere near the region, but expect confidence to remain low until models become better aligned. Some guidance is already hinting at MCSs or storm clusters developing upstream and potentially propagating towards central Indiana at times this weekend into early next week. Localized flooding from repeated rounds of convection and isolated damaging wind gusts would be the primary threats if this scenario occurs.

AVIATION (00Z TAF Issuance)

Issued at 615 PM EDT Tue Aug 4 2026

Impacts:

- Patchy fog possible towards daybreak.

Discussion:

VFR conditions expected through the TAF period. Any diurnal cu will quickly dissipate over the next two hours with the only impactful weather being patchy fog towards daybreak, mainly at LAF. Any fog will dissipate quickly after sunrise with diurnal ci returning later in the morning. Winds should become southwesterly, remaining under 10kt, as a cold front approaches from the west.

IND WATCHES/WARNINGS/ADVISORIES

None.