textproduct: Indianapolis

KEY MESSAGES

- Active pattern this week with near daily chances for showers and storms. Friday likely to be the driest day of the week.

- Scattered storms possible this afternoon and evening for Central and North Central Indiana, a few of which may be strong to severe.

- Near record warm temperatures expected through Saturday with multiple days in the 80s and lows in the 60s.

DISCUSSION (Today through Monday)

Issued at 319 AM EDT Tue Apr 14 2026

Through Tonight...

Central Indiana remains firmly within the warm sector of an elongated area of low pressure stretching from Minnesota into the Central Plains. Southwesterly flow remains in place aloft with numerous waves of energy within the mid and upper levels bringing renewed chances for convection in Indiana. While the main storm track over the next 24 hours remains to the west and northwest, closer to the surface fronts and area of low pressure, this pattern does support scattered convection developing or tracking near Central Indiana. A very warm and humid environment with modest shear aloft will support at least a marginal threat for severe weather for the next several days as this same pattern persists.

Current satelitte imagery and observations show an overnight MCS along a warm front in Wisconsin and Michigan while a dying area of showers and storms is located near St. Louis. CAMs guidance has a poor handle on the evolution of mesoscale features within this broad southwesterly flow regime within the warm sector; therefore forecast confidence on timing and placement of thunderstorm chances the next several days is fairly low. The greatest storm threat and timing will is all dependent on mesoscale and microscale boundaries which develop as these dying complexes of storms enter Central Indiana. This is a typical warm season set up where the forecast for the next 12 hours all depends on such small minute details which even CAMs struggle to resolve. Therefore, numerous forecast updates will likely occur as the convective set up for each day evolves.

Based on current trends early this morning, it appears the southern end of the MCS pushing into Northern Illinois may clip portions of North Central Indiana within the 6am to 9am timeframe as the MCS backbuilds to the southwest under a strong southwesterly LLJ aloft. Elsewhere across Central Indiana, higher clouds will continue to overspread the region from dying storms to the west and the approaching storms to the northwest. Not concerned with severe storms this morning; however based on current soundings showing steep low level lapse rates, any shower has the capability to bring down higher gusts aloft in the 40-55 mph range.

A lull in the precipitation chances is likely late morning through early afternoon across Central Indiana; however this is where there is lower confidence in the forecast. Will have to watch where leftover boundaries from this morning's convection set up as this will be where evening storms likely develop. Since Central Indiana is well within the warm sector away from synoptic level fronts, forcing along any leftover boundary will be fairly weak, keeping overall coverage of evening storms widely scattered. However, any storm does have the threat to be severe with all hazards on the table. 2000-3000 J/kg CAPE and 20-35 kts of shear will be enough to support a supercell threat along any of these boundaries. Current thinking is that along and north of I-70 will have the threat for these widely scattered storms 4PM to around 10PM. Will monitor how everything evolves through the day and provide forecast updates as confidence increases on exact locations of potential storm development and associated threats.

Outside of storms, deep low level mixing within a warm and humid environment with continued warm air advection will result in near record high temperatures in the 80s today for Central Indiana.

Wednesday through Saturday...

The overall pattern remains relatively the same going into midweek as the elongated area of low pressure and fronts slowly shift closer to Indiana. With southwest flow continuing aloft, any upper impulse moving through the flow will have the potential to generate scattered convection in an unstable atmosphere. Convection generated by the front to the north could also impact North Central Indiana at times. Isolated strong to severe convection is possible given expected parameters.

Temperatures on Wednesday depends on sky cover and rain coverage, but for now will go with upper 70s north to middle 80s south. No matter where convection forms, it will likely feel more like July than Mid April in this type of pattern with such high humidity levels.

Wednesday night into Thursday, an upper trough moves into the area, providing better forcing for more widespread storms. The surface front could move into the area, but there is a good amount of uncertainty on timing of greatest coverage for storms Wednesday night into Thursday depending on when the front moves through and also associated smaller shortwaves, which guidance likely can't resolve at this time. While confidence is high in more widespread rain and storm chances, timing and overall extent of the severe threat is still uncertain.

Brief upper ridging looks to move in on Friday, providing a dry and warm to hot day. A larger upper trough moves in on Saturday bringing a strong cold front through the area. This will result in another round of showers and thunderstorms, some possibly strong to severe once again.

Sunday and Monday...

A brief cool down expected for the region latter half of the weekend and into early next week. Longer range guidance continues to hint at upper troughing developing over SE Canada and the NE CONUS going into early next week, allowing for cooler airmasses from Canada to drop southward behind Saturday's front. Still uncertainty on the overall location and track of the incoming high pressure, but confidence remains high in a few days of much cooler weather and the potential for a few frosty mornings in the 30s. Highs will be below normal, with the coldest readings Sunday in the 50s. Lows in the middle to upper 30s may occur Saturday night and Sunday night. Frost potnetial is certainly there but confidence is only marginal at this time as the placement of the high pressure will ultimately determine if optimal conditions for radiational cooling and frost occur over Central Indiana or elsewhere within the Ohio Valley.

AVIATION (12Z TAF Issuance)

Issued at 638 AM EDT Tue Apr 14 2026

Impacts:

- Wind gusts up to 25 to 35 kts likely through the period - Scattered convection may impact sites 13-16z then again 21z-02z.

Discussion:

Satellite imagery and observations show Central Indiana firmly within the warm sector of an elongated area of low pressure in the Central Plains. Low level south-southwesterly flow will continue through the period with gusts of 25-35 kts to continue. Latest IND ACARs sounding still shows a well mixed boundary layer under an inversion at almost 2km agl. This is a fairly deep mixed layer for the early morning hours. With a strong nocturnal low level jet overhead, expect these stronger gusts at or above 35 kts to persist into the mid to late morning hours, diminishing some into the 20-25 kt range by the afternoon as the LLJ weakens.

Lower confidence forecast regarding convection in this type of pattern as short term hi-res guidance struggles to handle these early morning storm complexes. Watching two complexes of storms in Illinois with which could impact Central Indiana in the 12-16z timeframe. The northern complex which moved into Northern Illinois has a gust front pushing southward into Central Illinois with convection developing on the backside of the boundary. This gust front moving south in addition to a subtle MCV has enhanced convection in Central Illinois as well. As these complexes essentially merge and continue east, these storms should enter portions of north Central Indiana within the next couple hours. Expect the best chance for storms in the 13-15z timeframe before the low level jet weakens. There isn't much forcing to sustain these storms further east other than the LLJ, so as the LLJ weakens after 15z, these storms should quickly dissipate. KLAF has the best chance at seeing a storm, while KIND may get clipped as the storms are weakening. Kept a Prob30 group in for -TSRA. Brief periods of heavy rain, MVFR or worse cigs and vis likely under any shower or storm.

Leftover boundaries later this afternoon within a very unstable and moist airmass should result in some afternoon convective development within Central Indiana, mostly likely along and north of I-70 in the 20z-02z timeframe. These storms would have the potential to be severe if they get going. Low confidence in finer details in this pattern. Will be able to determine where the highest threat is later this afternoon once boundaries for storms actually develop. Even when storms do develop, they may be widely scattered, but still think the threat is high enough to include a Prob30 group for storms this evening for the sites along and north of I-70.

Cigs and vis should be largely VFR for the most part today, with brief periods of MVFR or worse conditions under any shower or thunderstorm. Brief periods of MVFR cigs this morning as a BKN025- BKN030 deck has developed within such a moist low level environment. Expect cigs to bounce between MVFR and low VFR this morning with convection in the vicinity.

CLIMATE

Issued at 300 AM EDT Mon Apr 13 2026

Within the setup described in the discussion above, near record temperatures are possible at times this week, mainly Tuesday, and Friday. Whether readings get close depends on sky cover and any rain staying away, which keeps confidence lower at this time.

Current deterministic model runs are cooler than the records, but the potential exists to get within a few degrees if everything lines up. On Tuesday April 14, Indy's record high is 85, set in 1883. On Friday April 17, Indy's record high is 87, set in 1896.

Record high minimum temperatures are also in play at times given the warm and relatively humid air mass. The first opportunity for this comes Monday, when the record high minimum at Indy is 63, set in 2014 and tied in 2018. At the moment, the forecast is for tying that number.

IND WATCHES/WARNINGS/ADVISORIES

None.