textproduct: Indianapolis

KEY MESSAGES

- Wet pattern through the week and into the weekend, with multiple rounds of showers and storms expected, which may produce occasionally heavy rainfall and renewed flooding along area waterways

- Potential for strong to severe storms at times, primarily late Thursday and again Saturday

- Strong non-thunderstorm winds expected Thursday and potentially Saturday, with frequent gusts of 35-40 MPH possible

- Drier and cooler weather for early next week

SHORT TERM (Today through Friday night)

Issued at 328 AM EDT Wed Apr 1 2026

An active pattern remains the expectation for the remainder of the week, with multiple opportunities for showers and thunderstorms, with one or more at least low chances for a strong storm or two.

A frontal zone continues to sag into the region this morning, currently draped from near St. Louis to Indianapolis/Muncie and Columbus, Ohio. This boundary, in part reinforced by a rain cooled airmass to its north, will continue to sag southward during the day and should stall near the southern border of the forecast area later today before lifting back northward as a warm front tonight into Thursday.

Relatively weak elevated instability north of the boundary will put a cap on embedded thunder chances today, though modest surface based instability should develop south of the front, wherever it happens to stall, and this, combined with the frontal forcing, will likely produce at least some scattered thunderstorm activity. Deep layer shear is strong enough to support some storm organization, so an isolated strong storm is not out of the question, though this limited threat will likely be slightly more likely to our east.

The primary concern will be at least a minor hydrologic threat as flow is aligned to a significant degree, though not perfectly, boundary parallel, which could produce areas of training in a background setting featuring precipitable water values near or above climatological max.

A bit of a lull in rain chances can be expected late tonight into early Thursday as the area reemerges into the open warm sector with the warm front pushing rapidly northward in response to a strong surface low and upper level wave moving northeastward out of the central Plains into the upper Great Lakes.

The shower and thunderstorm threat will ramp back up again on Thursday afternoon into Thursday night as one or more rounds of prefrontal convection associated with the aforementioned system move through the region. Deep layer shear will remain plentiful, and low level shear will be substantial as well owing to strong low level flow and some veering in the warm advection regime. The degree of destabilization is in question giving the threat a somewhat conditional nature, but even modest instability in such a flow environment would pose at least a decent wind threat with minimal trouble mixing down 50+KT flow within a few thousand feet of the surface, as well as concern for a tornado or two.

Outside of thunderstorms, Thursday will again be quite windy, with PBL mixing and steep low level lapse rates likely able to mix down frequent gusts of 35-40 MPH with isolated higher gusts possible. Similar gusts may be possible on Saturday as well depending upon the depth of mixing.

This low will be followed in quick succession by another similarly strong system Friday into Saturday, which will hold up the front from fully pushing through the area until this second low passes Saturday. Despite continued strong deep layer shear, instability is an even larger question during this time frame, though at least an isolated strong to severe storm threat would appear possible then as well.

Throughout this period, deep moisture and the potential for repeated rounds of moderate to at times heavy rainfall will gradually increase the hydrologic concern across the region, and a localized flash flood threat may grow with time, and hydrologic ensembles show a fairly high likelihood of portions of the main stem rivers returning to at least minor flood, particularly along the Wabash, and portions of the lower White and East Fork White.

Temperatures will be well throughout the vast majority of the week, though a strong cross-boundary temperature gradient will exist today and tonight across central Indiana. Temperatures will frequently be 15-25 degrees above average until frontal passage this weekend.

LONG TERM (Saturday through Tuesday)

Issued at 328 AM EDT Wed Apr 1 2026

Saturday and Saturday Night...

Active weather looks to finally come to an end on Saturday and Saturday Night. As we being the day, models suggest ridging aloft over the eastern Great lakes departing, but a cut off low will be found over the upper midwest. This will place Central Indiana still within the SW flow aloft. The cut off low and an associated moderate upper trough will push toward and across Central Indiana, allowing plenty of upper support to arrive in Indiana through the day. Within the lower levels Central Indiana will start the day within the warm sector, and a cold front will push across the state through the afternoon and into the evening. Forecast soundings at this early stage suggest a deeply saturated column passing, with little CAPE, through the afternoon. Subsidence and drying is shown to arrive on Saturday night after 00Z. Thus confidence will be high along with high pops for Saturday at this time. Pops will need to be tapered off on Sunday night as the moisture exits and drying, subsidence and cold air advection arrives.

Sunday through Tuesday...

Quiet and cooler weather is expected on Sunday through Tuesday, as strong ridging is expected to take shape over the western CONUS. This will result lee side northwest flow to spill from Central Canada into the Ohio Valley on Sunday through Tuesday. Meanwhile at the surface strong high pressure is suggested to settle across the plains, resulting in a continued flow of cool and dry Canadian air across Central Indiana. On Monday, there is a caveat. Models show a weaker short wave within the NW flow aloft streaming across the Great Lakes. While this will provide some upper support, precipitation chances appear minimal as moisture sources are limited. Lower levels are suggested to remain dry as mid level clouds pass with this feature. Thus will keep a dry forecast at this time, but it will be something to watch over the next few runs to see if enough forcing could be present to squeeze out some very light precipitation. Otherwise, we will expect a few more clouds on Monday as these features pass.

More sunshine and cooler weather should arrive on Tuesday as ridging is expected to re-establish itself over the upper midwest, providing subsidence and dry air flowing into Indiana. Temperatures on Sunday through Tuesday will be at or below seasonal normals, thus highs mainly in the 50s.

AVIATION (06Z TAF Issuance)

Issued at 118 AM EDT Wed Apr 1 2026

Impacts:

- Showers with some embedded thunder, particularly at LAF

- Ceilings deteriorating through MVFR to IFR at all but BMG through daybreak

Discussion:

A boundary continues to slowly sag into the area, with winds shifting to the north and then northeast behind it. The majority of precipitation and thunderstorm activity are elevated north of the boundary, and this will largely remain the case, though more shower activity will overspread the sites as the boundary pushes south.

A stout frontal inversion north of the boundary will promote deteriorating ceilings and perhaps visibilities, with IFR likely to dominate most of the sites by daybreak and through much of the rest of the period. BMG may remain MVFR once it falls to that level but the gradient between IFR and VFR may be tight, so uncertainty is high there.

Will only mention thunder at LAF, though a low chance for embedded thunder cannot be ruled out at the other sites. Uncertainty is too high for too long to narrow down a particular time frame at this point for a PROB30.

Winds will gradually shift to the north and northeast through the period, becoming easterly this evening. This boundary will begin to push back northward as a warm front beyond the TAF period.

IND WATCHES/WARNINGS/ADVISORIES

None.