textproduct: Indianapolis

KEY MESSAGES

- Quiet weather with near normal temperatures today and tonight

- Showers and thunderstorms return late on Friday and continue through the weekend. There is an excessive rainfall threat Friday night through Saturday for most of central Indiana.

- Warming trend likely for the first week of August

DISCUSSION (This evening through Thursday)

Issued at 116 PM EDT Thu Jul 30 2026

Surface high pressure has built into the region and a cool and a dry air mass is in place. Temperatures have risen into the low-mid 80s and dew points have dropped into the mid 50s in a few places. Efficient boundary layer mixing has allowed dew points to fall below guidance (as low as the 5th percentile). Additionally, high temperatures may run a few degrees above guidance. Still, near average readings are expected this afternoon.

Surface high pressure along with light and variable winds may allow for patchy fog tonight like previous nights. However, increasing high cloud cover tonight may limit coverage in comparison. Fog is most probable along rivers and in rural/agricultural areas.

Aloft, troughing over the northeastern US will promote northwesterly flow across the Midwest. Ensemble guidance is in good agreement showing a shortwave trough diving southeast within this flow, arriving later Friday evening. Showers and thunderstorms are possible as early as Friday night. Guidance then slows the shortwave down as western ridging amplifies. This should bring higher rain probabilities into the day Saturday, potentially into early Sunday. Locally heavy rainfall amounts are possible owing to the slow system motion.

Looking into next week, the weekend shortwave departs eastward while the polar jet lifts north. Though there is no strong signal for either troughing or ridging, the jet stream residing well to our north should allow temperatures to creep upwards. A warming trend is therefore favored next week with highs potentially reaching into the upper 80s / near 90 at times. Some guidance keeps the jet stream active, with frequent storm systems embedded within the broader flow. This may act to keep daily precipitation chances above average through next week as well. However, the signal regarding precipitation is less clear than for temperatures.

AVIATION (18Z TAF Issuance)

Issued at 116 PM EDT Thu Jul 30 2026

Impacts:

- Low probability ground fog tonight

Discussion:

VFR conditions expected through the TAF period.

Surface high pressure directly over central Indiana will provide quiet weather through tonight. Diurnal cumulus around 5000 ft agl should dissipate around 00z. High cirrus begins to arrive overnight ahead of an upper-level low pressure approaching from the west. Mid and high-level cloud cover thickens late in the TAF period as the upper-low arrives Friday evening.

Winds should remain light and variable today into tonight, becoming southerly on Friday as high pressure slides eastward. Patchy fog is possible tonight but less coverage compared to recent nights owing to increasing high clouds.

IND WATCHES/WARNINGS/ADVISORIES

None.