textproduct: Indianapolis

KEY MESSAGES

- Scattered thunderstorms expected to continue through Saturday night

- Localized heavy rain and minor flooding being the primary threats

- Drier and increasingly warm conditions late Sunday through the middle of next week as high pressure builds

DISCUSSION (Today through Friday)

Issued at 131 AM EDT Sat Jul 11 2026

Overview.

A quasi-stationary frontal boundary will keep thunderstorms in the area through Saturday night. Because these storms will move slowly and may repeat over the same areas, localized flooding will be the primary weather hazard. Rain chances afterwards look low with temperatures will be slightly above normal, averaging in the mid to upper 80s, but dew points are expected to remain in the upper 60s to low 70s which will limit the more extreme heat threat.

Rest of Tonight.

Low stratus and patchy fog are likely into the morning hours due to weak low-level wind fields and high residual low-level humidity. The 00Z HREF/REFS are honing in on an area mainly across Illinois, but stretching into southwestern Indiana where flood probabilities will be high with rainfall rates of 1-2 inches per hour at times. Some spotty 3 to 4+ inch rainfall totals will be possible given the slow storm motions. Will continue to monitor the radar trends and issue flood products accordingly.

Saturday Through Sunday.

The near-term synoptic pattern will be characterized by a quasi- stationary frontal boundary draped across the region, held in place by a flat sub-tropical ridge centered over the Gulf Coast states. Within this weak steering regime, successive low-amplitude mid-level shortwaves will track along the frontal zone and interact with a deeply saturated atmospheric profile with PWAT values near 1.5 to 1.8 inches. Mesoscale model guidance, including the HREF and its component members, show modest mid-level lapse rates and weak deep- layer vertical wind shear under 20 knots, which will limit overall storm organization and keep the severe weather risk low.

However, high precipitation efficiency within a deeply saturated profile raises the potential for localized heavy rainfall and training cells, especially towards south central Indiana. By Saturday afternoon, the front is forecast to be in the southern portions of the forecast area, shifting the primary convective focus to central and southern Indiana while the northern counties experience a gradual drying trend from north to south. By Sunday morning, rain chances will be limited to just the far southern counties with little to no rain chance towards I-70 and points to the north.

Monday through Friday.

Global ensembles, including the GEFS and EPS, are in good agreement in a broader synoptic pattern shift beginning Sunday. The departing upper trough will move eastward, allowing broad mid-level ridging over the central United States to expand into the Great Lakes and Ohio Valley. From Monday through Wednesday, strong large-scale subsidence beneath the core of the building ridge will suppress convective development entirely, keeping conditions dry across central Indiana. As the ridge axis centers over the area, low-level thermal profiles warm significantly, with 850 mb temperatures progged to reach 18-20C. This will translate to surface high temperatures rising from the upper 80s on Monday to near 90 by Tuesday and Wednesday. Surface dewpoints in the upper 60s to lower 70s will yield heat indices climbing into the mid-90s.

Toward Thursday, ensemble guidance hints at the ridge retrograding slightly toward the western United States, placing the Great Lakes into northwest flow aloft, which could introduce a weak northern stream shortwave and a return of convective chances late in the period. Confidence is low on details, but somewhere in the Ohio Valley will likely end up being impacted by convective clusters riding the ridge to the southeast.

AVIATION (06Z TAF Issuance)

Issued at 131 AM EDT Sat Jul 11 2026

Impacts:

- MVFR to IFR cigs/vsbys through 10Z due to convection - Additional MVFR to IFR cigs/vsbys due to low stratus/fog 10Z through 13Z

Discussion:

Showers and storms are expected to continue through daybreak, mainly at HUF and BMG with lower chances at LAF and IND. Lowered vsbys will be the main threat with brief periods of IFR in the heavier showers. Outside of convection, low stratus and fog is expected again this morning starting around 10Z and continuing through 13Z with periods of MVFR to IFR. Some brief LIFR fog is possible, but confidence is too low at this time to add to the TAF. Winds will generally be out of the north to northeast through the TAF period at 5-10kts outside of near calm conditions towards daybreak today.

IND WATCHES/WARNINGS/ADVISORIES

None.