textproduct: Indianapolis

KEY MESSAGES

- Flood Watch in effect through 8AM Thursday across the northern half of central IN with localized flash flooding possible

- Scattered to numerous showers and storms are expected this afternoon into tonight, isolated severe storms are possible

- Generally drier late this week through early next week, but there is a chance for showers and storms late Friday into Saturday

FORECAST UPDATE

Issued at 1004 PM EDT Wed Aug 19 2026

Showers and thunderstorms continue across the northern half of central Indiana this evening. Additional convection has developed in central and northern Illinois, with isolated cells even developing in northern Indiana.

These were forming in a moist atmosphere along a slow moving surface front as well as numerous outflow boundaries across the region. Some upper energy and mid level jet dynamics is also helping generate the convection, especially over Illinois.

Convection across central Indiana will continue to slowly move south. The slow movement will keep the threat for heavy rain and flash flooding around. With the upper influence, the convection across central Illinois should move southeast into the area into the overnight (as the surface front slowly sinks south).

Some instability and shear exist, and KILX's radar has been showing strong to near severe winds not far off the surface with the central Illinois convection. Given these, isolated severe storms will remain possible tonight. The best parameters may develop south of the forecast area, per the latest Storm Prediction Center Mesoscale Discussion.

Have slowed the progression of higher PoPs based on these trends. Will likely have to make further adjustments depending as convection evolves.

DISCUSSION (This evening through Wednesday)

Issued at 332 PM EDT Wed Aug 19 2026

As of this afternoon, scattered thunderstorms have popped up across north-central Indiana. There is a marginal severe threat this afternoon through the evening with isolated damaging winds possible and some hail as well. With how saturated the ground is, trees could more easily be knocked over.

Flooding continues to be the main threat for the forecast area unfortunately. Some of these afternoon storms are already producing rain rate of over 2 in/hr, across northern portion of the forecast area. A flood watch is in effect through the morning. Rivers and creeks are likely to rise again from this rain. Where exact impacts occur will depend on which river basin the highest amounts of rainfall fall. Models have been largely highlighting that some of these highest amounts will fall over the White River basin, which could lead to river points along the White within Indianapolis to return to action stage by the weekend and can't rule out a chance of brief return to Minor flooding too.

Rivers remain high across the area, continue avoiding flood waters and stay out of rivers.

Behind the wave, northwest flow will become more dominate aloft as upper high pressure builds over the desert SW and upper troughing builds to the NE of the forecast area. Meanwhile at the surface, weak high pressure will generally be in the region leading to a mostly dry rest of the forecast period outside of periodic chances for showers and storms. Saturday seems to be the next best chance of precipitation but again, those are still low chances. Temperatures throughout the forecast period will see highs in the upper 70s to low/mid 80s and lows from the upper 50s to mid 60s.

AVIATION (06Z TAF Issuance)

Issued at 1252 AM EDT Thu Aug 20 2026

Impacts:

- Scattered SHRA/isolated TSRA ending north to south through 10Z. - FG/low stratus likely overnight for most terminals.

Discussion:

Weak cold front located from near Terre Haute to north of Cincinnati will continue to push south through 12Z. Near this boundary, scattered SHRA will persist through 08Z to 10Z, with embedded TSRA possible near KIND/KBMG/KHUF. Low stratus and/or BR/FG resulting in MVFR to IFR conditions are likely after 08Z to 10Z, with CIGs below 500ft AGL possible, especially near areas that received the heaviest rainfall Wednesday evening. Additional visibility reductions and MVFR/IFR conditions are possible Thursday night. Winds behind the front will remain northerly (010-040 degrees true) through the TAF period, with speeds generally remaining 7 knots or less.

IND WATCHES/WARNINGS/ADVISORIES

Flood Watch until 8 AM EDT Thursday for INZ021-028>031-035>049- 054>057.