textproduct: Indianapolis

KEY MESSAGES

- Quiet pattern continues through Wednesday amid light winds and near normal temperatures, patchy fog early today 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

FORECAST UPDATE

Issued at 923 PM EDT Tue Aug 4 2026

No major changes needed to the ongoing forecast with conditions generally evolving as expected. The cu field continues to dissipate across the area, leaving clear to mostly clear skies for most of central Indiana with only a few high clouds. With loss of heating and high pressure nearby, winds have diminished and remain variable. Fog coverage looks fairly minimal across the area with another well-mixed day today, but favored areas such as river valleys will likely see at least some patchy fog along with shallow corn field fog.

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 (06Z TAF Issuance)

Issued at 115 AM EDT Wed Aug 5 2026

Impacts:

- Patchy fog possible towards daybreak

Discussion:

VFR conditions expected through the TAF period outside of very brief fog towards daybreak. Confidence in fog is highest at LAF, but chances are too low for a mention in the TAF at this time. Any fog will dissipate quickly after sunrise with diurnal cu returning later in the morning. Winds will be light and variable at less than 5kts through the night before becoming predominately southwesterly at 5- 8kts towards the late morning hours.

IND WATCHES/WARNINGS/ADVISORIES

None.