textproduct: Indianapolis

KEY MESSAGES

- Generally dry today with temperatures in the mid to upper 80s, low chance for rain in southern Indiana

- Strong to severe storms and flash flooding possible late Thursday into Thursday night

- Additional rain Friday through the weekend with pockets of flooding

FORECAST UPDATE

Issued at 937 AM EDT Wed Jul 8 2026

The forecast remains in good shape with only minor adjustments needed. Current KIND Radar imagery depicts isolated showers and storms south of the forecast area with quiet weather conditions across central Indiana. The isolated convection is associated with a weak mid-upper level disturbance which will crawl northward during the day. This may support isolated showers or storms over far southern counties by the afternoon. Otherwise, expect weak surface high pressure to remain the dominant weather feature promoting quiet weather for most areas. Look for another warm, but near seasonal day in the mid 80s.

DISCUSSION (Today through Tuesday)

Issued at 123 AM EDT Wed Jul 8 2026

Overview.

Dry and pleasant weather is expected for today with highs topping out in the mid to upper 80s. On Thursday, a strong cold front will move into the region, bringing a risk for severe thunderstorms and heavy rainfall that could cause flash flooding Thursday night. This front will then stall over the area, keeping chances for showers and storms in the forecast from Friday through the weekend and into early next week, leading to the potential for flooding with total rainfall amounts of 2 to 4 inches.

Today through Thursday.

The broader synoptic pattern today features mid-level ridging centered over the Ohio Valley that will gradually suppress southward as a northern stream shortwave trough digs across the upper Great Lakes. At the surface, high pressure positioned over the eastern Great Lakes will maintain a dry easterly to southeasterly low-level flow across central Indiana. Forecast soundings exhibit a notable mid-level subsidence inversion along with deep dry air. This dry airmass and large-scale subsidence will inhibit convective development today, keeping the entire forecast area dry with afternoon high temperatures rising into the mid-80s.

The synoptic pattern transitions rapidly on Thursday as a northern stream shortwave trough deepens over Ontario, driving a surface cold front south-southwestward toward the area. Ahead of this boundary, a robust low-level jet will advect an anomalously moist, tropical airmass northward. PWAT values are modeled to surge toward 2.00 to 2.25 inches, which sits well above the 90th percentile for early July. HREF and ensemble guidance indicates rapid destabilization Thursday afternoon ahead of the front, with MLCAPE expanding to 1500- 2500 J/kg. Convective initiation is expected along and ahead of the front by late Thursday afternoon and evening. While deep-layer shear remains modest at 25-35 knots, linear forcing along the front will support organized multicell clusters and transient supercell structures. Damaging downburst winds and isolated severe hail represent the primary convective hazards.

A flash flooding threat will develop Thursday night. As the surface front slows down and aligns parallel to the mid-level westerly flow, Corfidi vectors indicate a high potential for cell training. Warm-cloud depths exceeding 12,000 feet will optimize warm-rain processes, yielding exceptionally high precipitation efficiency. Localized rainfall rates exceeding 2 inches per hour are anticipated, capable of producing widespread flash flooding and areal flooding across central Indiana overnight.

Friday Through Tuesday.

From Friday through the weekend, the surface frontal zone is forecast to become quasi-stationary across the Ohio Valley as it encounters a flat sub-tropical ridge anchored over the Gulf Coast states, blocking its southward progression. Within this weak steering regime, successive low-amplitude mid-level shortwaves will track along the frontal zone, interacting with the lingering tropical moisture reservoir where PWATs remain elevated between 1.75 and 2.00 inches. This setup will support daily rounds of convective clusters and multi-cell arrays through Sunday.

Medium-range ensemble guidance (GEFS and EPS) exhibits high consensus regarding a prolonged, heavy rainfall footprint across the Ohio Valley due to this stalled boundary. Probabilistic guidance indicates a 60-80% chance of widespread total rainfall exceeding 2.00 inches across central Indiana through Sunday evening. Within corridors experiencing persistent convective training or repeated cell tracking, probabilistic clusters indicate a 30-40% chance of localized totals exceeding 4.00 inches. Given the saturated antecedent conditions expected from Thursday night's convection, this additional rainfall will sustain and exacerbate risks for river flooding and ongoing areal flooding through the weekend.

The unsettled pattern will gradually transition into early next week as the main upper-level trough shifts into eastern Canada, allowing northwest flow aloft to develop over the Midwest. While the primary stalled frontal boundary will diffuse or push slightly south of the state, embedded shortwaves within the northwest flow will maintain daily chance-level probabilities (30-50%) for showers and thunderstorms. Temperatures throughout the period will remain near or slightly below seasonal normals in the low to mid-80s due to widespread cloud cover and precipitation, though high ambient dewpoints in the lower 70s will maintain elevated humidity levels.

AVIATION (12Z TAF Issuance)

Issued at 542 AM EDT Wed Jul 8 2026

Impacts:

- None

Discussion:

VFR conditions expected through the TAF period outside of brief MVFR vsbys at BMG through 13Z. Diurnal cu is expected to develop towards 15Z with coverage expected to remain FEW to SCT. This cu will dissipate towards 00Z with high cloud coverage increasing through the night tonight. Winds will generally be light and variable through the TAF period, predominately out of the north through daybreak, then west to southwest during the day.

IND WATCHES/WARNINGS/ADVISORIES

None.