textproduct: Indianapolis

KEY MESSAGES

-Dry conditions persist through the early evening with high temperatures in the mid to upper 70s

-Rain arrives tonight into Sunday as tropical remnants move into the Ohio Valley with a potential sharp cutoff in rainfall on the western edge

-Another round of rain likely mid to late week as another low pressure moves through

DISCUSSION (Today through Friday)

Issued at 135 AM EDT Sat Oct 10 2026

Today Through Sunday.

Surface high pressure migrating exiting the Mid-Atlantic coast will maintain dry conditions and southeasterly flow across central Indiana on through the day today with increasing cloud cover. These clouds will keep temperatures cooler across the southeastern counties with highs in the mid 70s while areas towards Lafayette may get close to 80 as the thicker clouds don't arrive until mid to late afternoon.

Primary focus remains in the overnight through Sunday timeframe as the remnants of Isaias move into the Ohio Valley. There remains considerable spread among deterministic and ensemble guidance regarding the western extent of the associated precipitation shield. The latest GFS and GEFS solutions continue to favor an eastward track, keeping the primary moisture axis and associated heavier rain focused over Ohio and eastern Kentucky. In this scenario, rainfall amounts will be fairly minimal with the potential that rain amounts remain a quarter inch or less for much of the areas west of I-69.

Conversely, the NAM and a few higher resolution models support a slightly deeper phasing of the northern and southern streams, pulling the remnant low and associated mid-level deformation zone further west. This solution brings a broad shield of light to moderate rain as far west as the Illinois border, yielding 0.25 to 0.75 inches of rainfall for the western half of the CWA and amounts greater than an inch towards the southeast. High-resolution guidance from the HREF highlights a remarkably sharp precipitation gradient on the western periphery of the system. Strong easterly flow aloft will encounter a persistent dry airmass over the mid-Mississippi Valley which leans more towards the lower-end precipitation solution, especially for the western and northwestern portions of the forecast area.

Regarding timing, isentropic ascent and saturation will gradually overcome the dry antecedent airmass after 21Z Saturday, with peak precipitation rates occurring between 00Z and 06Z. Forcing will quickly exit to the east by Sunday morning as the primary trough axis pivots eastward with any precipitation remaining closer to the Ohio border. High temperatures will range from the upper 70s in the west where clouds will clear early to around 70 in the east where clouds will stick around through the day.

Monday Through Friday.

Mid-level ridging and surface high pressure will build across the region on Monday, initiating a period of stronger WAA and bringing near record temperatures to Illinois and portions of western Indiana. These much warmer than normal temperatures will continue into Tuesday before the pattern begins to shift towards mid to late week.

Medium-range guidance show a more significant pattern amplification for the middle and end of next week. A deep longwave trough will eject out of the Rockies on Wednesday, driving rapid cyclogenesis over the Upper Midwest. Strong CVA and favorable upper-level jet coupling will provide robust dynamic forcing across the Ohio Valley. A sweeping cold front will cross central Indiana late Wednesday into Wednesday night, accompanied by widespread precipitation.

Post-frontal CAA will bring temperatures back to near normal by Friday with high pressure building across the Ohio Valley. Looking towards the weekend, this cooler pattern along with a drier airmass may bring the first potential for frost Saturday night into Sunday.

AVIATION (06Z TAF Issuance)

Issued at 135 AM EDT Sat Oct 10 2026

Impacts:

-Easterly wind gusts to 20kt at IND and BMG after 00Z -MVFR cigs and rain after 00Z, mainly between 00Z and 06Z

Discussion:

VFR conditions expected through much of the day today before remnants from Isaias bring wind gusts, rain, and lowered cigs after 00Z. Rain coverage will be greatest at IND and BMG along with stronger winds with the potential for little to no impacts towards HUF and LAF beyond brief light rain. The thunder potential is too low for a mention in the TAF, but can't rule out a brief rumble. The heaviest showers will also bring brief reduced vsbys, but those should be infrequent.

IND WATCHES/WARNINGS/ADVISORIES

None.