textproduct: Indianapolis

KEY MESSAGES

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

- Strong to severe storms possible late today into tonight, as well as Friday afternoon and evening into Saturday; all hazards possible, though damaging winds will be the primary concern

- Drier and cooler weather for early next week. Potential for lows in the low to mid 30s Monday through Wednesday mornings; Frost or freeze conditions possible

FORECAST UPDATE

Issued at 956 PM EDT Thu Apr 2 2026

Severe storms across central Indiana have come to an end for the moment as the instability essentially dropped off. An unorganized line of lighter rain continues eastward from a line near Muncie down to Bedford. As for the forecast, updated the temps and PoPs to match current observations. Temperatures behind the line have dropped into the 60s while it remains in the 70s ahead of the front. Overnight lows are expected to remain in the 60s, potentially dropping into the upper 50s in the far NE.

Currently, there is another broken line of showers and thunderstorms stretching from Illinois to Missouri that could reach the area later tonight. As of now, thinking that these should weaken as they approach central Indiana but we will continue to monitor these storms to see how they trend in the coming hours.

MESOSCALE UPDATE

Issued at 557 PM EDT Thu Apr 2 2026

Surface mesoanalysis shows an instability axis extending across the MS river valley, which much lower instability located over central Indiana, (MLCAPE around 500 j/kg). ACARs soundings from IND and the 18Z sounding from Lincoln, IL show a pronounced inversion centered around 500 mb, which is substantially limiting mid level lapse rates to less than 6 deg C/KM. However there are steep lapse rates between the surface and 3 km. DCAPE values measuring downdraft potential run between 500-800 j/kg extending along and just east of the Wabash valley. The threat for severe hail looks extremely minimal given the weak mid level lapse rates and overall instability. In addition given cloud bases around 5kft the and meager low level shear, the threat for any isolated tornado is very low.

Given the organized nature of the convective line in Illinois, cell mergers and cold pool generation will foster some threat for damaging wind gusts as the activity moves eastward into central Indiana. The leading edge of the threat for severe winds will reach the US 31 corridor around 8 PM EDT.

SHORT TERM (This evening through Friday)

Issued at 302 PM EDT Thu Apr 2 2026

An active next 24 hours expected for Central Indiana with strong winds and a few rounds of potentially strong storms.

Soundings from around the region show a mixed boundary layer resulting in strong winds within the low level jet mixing down to the surface. The Wind Advisory remains in effect through 7PM for sporadic gusts to 45 mph. Winds remain elevated overnight; however gusts should drop off after sunset and remain under 30 mph through Friday.

Satellite imagery and observations show Central Indiana firmly within the warm sector of a 1000mb low near Des Moines, IA. The overall system shifts to the northeast tonight into the Great Lakes while weakening, taking the best forcing for ascent and wind shear with it. A trailing surface front stalls out tonight over North Central Indiana as the entire system pulls away. While this isn't the best scenario for strong to severe storms, there is still a marginal threat for severe weather this evening and tonight.

Latest IND ACARs sounding shows a moist boundary layer with dew points around 60F and CAPE nearing 500 j/kg. CAPE isn't overly impressive and is expected to wane some going into this evening as mixing dries out the boundary layer some. Also noting weak mid to upper level lapse rates which could limit the overall severity and coverage of storms as they track east into Central Indiana. CAMs have been consistent in showing plentiful shear to support strong to severe storms, however the overall profile including instability and upper level lapse rates are only marginal. And with the best dynamics and forcing closer to the parent system, confidence is increase in the best severe threat remaining closer to the IL/IN border and in NW portions of Central Indiana. 18z ILX special sounding confirms the marginal environment for severe weather this afternoon. In fact, the environment over Central Illinois is a little more supportive for supercells this afternoon with more instability and higher shear. Latest Hi-res guidance does show storm initiation within the 19-21z timeframe in South Central Illinois and near the MO border , however hi-res ensemble probs depict storms struggling to vertically grow above 30kft. Based on the current environment and hi-res guidance trends, thinking the best chance at any severe storm will likely remain in Western Indiana before sunset with damaging winds being the main threat. But as mentioned above, the limiting factors to severe weather should prevent the high wind or tornado threat from being widespread in Indiana. Nonetheless, best timing for storms to approach the IL/IN border is around 22z- 23z, pushing east/ northeast 00z-02z into Central Indiana. Do think discrete cells will begin to merge into a mixed mode line with embedded lower topped supercells and bowing segments. There is a strong signal that storms fall apart during their eastward progression as the entire mid latitude system and supportive dynamics pull away. Lower confidence exists in any severe threat this evening and tonight east of the I-65 corridor.

In addition to the marginal severe threat, any thunderstorm has the potential to produce heavy rain and flash flooding, especially in areas that get repeated rounds of storms tonight where 1-2" of rain could fall locally. Outside of those localized areas, widespread rainfall amounts through tonight should remain around or below a half inch.

Later tonight, The cold front won't make it fully into the area before pushing back northward in response to development and northeastward movement of another low pressure system tonight into Friday. This set up keeps the area within the warm sector and continuing thunderstorm potential into the day on Friday. With the increase in the LLJ ahead of the front overnight, CAMs has been consistent in showing additional storms developing in the 04-08z timeframe within Central Indiana. Weak, yet positive theta-e and moisture advection right along the front may increase instability enough to support a few storms overnight. With a marginally unstable and humid environment and sufficient shear still present for organized storms, would not be surprised to see a strong to severe storm or two behind the main line of storms. This secondary round likely will not be as widespread as the first round, remaining more isolated to scattered in nature. A marginal damaging wind and hail threat exist with this second round but not expecting anything significant.

For Friday, Soundings indicate early day capping eroding eventually being overcome by diurnal heating, with much better instability in a modest shear environment supporting potential for strong to severe storms Friday afternoon into evening as the front remains draped over North Central Indiana. Overall, Friday should not be a washout of a day. Expect cloudy, warm, and humid conditions the first half of the day with storms developing along the front within Central Indiana during the afternoon. Highs once again will be above average in the 70s to near 80.

LONG TERM (Friday night through Thursday)

Issued at 302 PM EDT Thu Apr 2 2026

A progressive and modestly amplified upper-level flow pattern currently exists across the CONUS. Broad troughing is found over the western US with ridging over the east. Low-level flow has largely been out of the southwest across the Mississippi and Ohio River valleys, which has lead to generally warmer-than-average temperatures over the past week. Additionally, occasionally shortwaves have been ejecting from the deeper trough over the west. These features have provided us with periodic chances for showers and storms as well.

Things change as we head into the long range, however, as the western trough begins to drift eastward. By late Sunday into early Monday, the trough axis is modeled to be over the Great Lakes. Northwesterly flow aloft returns to the Midwest, with colder air streaming southward. Ensemble guidance is in good agreement showing a trend towards cooler temperature through much of next week. Near to slightly below normal readings are favored, with daily highs in the 50s to near 60 and lows in the 30s. Multiple nights next week have the potential to be near or even below freezing. As such, the probability of frost and freeze conditions is increasing.

Days 8 - 14: Longer range ensembles hint at a return to the current pattern, featuring troughing out west with ridging to the east. A trend towards warmer-than-average temperatures and a more active storm track is favored around mid-month.

AVIATION (00Z TAF Issuance)

Issued at 656 PM EDT Thu Apr 2 2026

Impacts:

- Line of convection will move through the sites from west to east through about 04Z

- Gusty winds will continue early, but speeds will gradually diminish

- MVFR ceilings return overnight and will persist into Friday

Discussion:

A line of convection will move east through the sites this evening. Strong to severe convection is possible. Otherwise, gusts over 40kt and IFR conditions are possible in any storm.

After the line passes, VFR conditions will persist for a time. Additional scattered convection will be around, but confidence is not high enough to include any mention of thunder.

MVFR ceilings will move in overnight and persist into Friday, potentially until mid-afternoon. Additional showers and some storms may develop Friday afternoon.

IND WATCHES/WARNINGS/ADVISORIES

None.