textproduct: Indianapolis

KEY MESSAGES

- Showers and thunderstorms likely late tonight

- Record temperatures in the lower 80s are possible on Thursday

- Showers and thunderstorms expected late Thursday into Thursday night with severe storms possible

- Cooler on Friday, with a warming trend resuming over the weekend

FORECAST UPDATE

Issued at 955 AM EDT Wed Mar 25 2026

Main focus for today's forecast will be the potential for an elevated fire weather threat this afternoon due to dry and breezy conditions. A broad area of low pressure over the Northern Plains shifts east through the upper Great Lakes region today, placing Indiana firmly within the warm sector with an increasing southwesterly low level jet. Strong boundary layer heating and warm air advection will lead to steep low level lapse rates and a deep mixing layer into a modest 20-25 kt LLJ. Expect stronger gusts aloft to mix down to the surface beginning late morning and persisting through around sunset with gusts upwards of 30 mph at times. IND ACARs soundings show a very dry profile in the lowest 3km, indicating the likelihood of dry air mixing down to the surface later today, working to drop RH values into the 20-25% range where mixing is deeper than what short term guidance depicts. While this should allow for a significant diurnal range today as highs make a run for 70 degrees, this pattern is also supportive of elevated fire weather conditions. Winds should decrease around and after sunset with both RH and dew points quickly rising overnight ahead of a shortwave and associated precipitation.

SHORT TERM (This afternoon through Thursday)

Issued at 630 AM EDT Wed Mar 25 2026

Expect quiet weather today under the influence of surface high pressure centered east of the region. Warm air advection aided by return flow and partly cloudy skies should quickly warm temperatures through the day. Look for highs in the upper 60s to low 70s. Deep diurnal mixing favors low minimum RH values around 25-30% this afternoon. Occasional gusts between 15 to 25 mph are also expected.

Increasing coverage of clouds appears likely into tonight as a subtle mid-upper level wave moves through. This feature along with increasing isentropic ascent and a strengthening nocturnal LLJ will also promote elevated convection, mainly late overnight. Severe weather is not expected at this time due to relatively weak instability. That said, loose storm organization from increasing deep-layer shear and the elevated nature of this convection could still support small hail.

Continued warm S/SW flow and clouds will help keep temperatures very mild overnight. Look for lows to range from the mid 50s to near 60F.

LONG TERM (Thursday through Tuesday)

Issued at 314 AM EDT Wed Mar 25 2026

Anomalous ridging continues to dominate the synoptic pattern over the CONUS. Low-amplitude troughing persists over the northeastern US and eastern Canada. Wedged between these two dominant features, Indiana's weather will be influenced strongly by progressive northwesterly flow aloft. This pattern has been in place for a while, and has been defined by warmer-than-average temperatures interrupted by brief but potent cold fronts.

We are currently in a warming trend which continues today with surface flow becoming southwesterly. Warm air advection intensifies as a SWrly low-level jet develops ahead of an approaching shortwave trough. After a round of showers and thunderstorms (see short term section for details), warm air advection peaks during the day Thursday. High temperatures sore into record territory with highs in the low to mid 80s. Additionally, moisture advection will help it feel muggy with dew points into the 60s.

Fast-moving, relatively weak surface low pressure zips by well to our north during the day Thursday. While this feature is helping drive the potent low-level jet leading to our warm air advection, it will also drive a strong cold front southward after it passes by. This front should act as a focal point for convective development later Thursday evening into Thursday night.

THURSDAY SEVERE WEATHER POTENTIAL

Guidance is in very good agreement now showing widespread convective development after about 8pm Thursday. Wind shear is abundant due to a strong jet stream just to our north. Shear vectors are roughly, but not quite, parallel to the aforementioned cold front. This should allow initial development to be somewhat discrete. However, strong frontal forcing combined with the nearly parallel flow should cause activity to grow upscale rather quickly.

Model soundings show deep layer CAPE of around 1500 J/Kg with an equilibrium level (EL) near 12km. Long curved hodographs support supercell development especially with initial discrete convection. Given very steep mid and upper-level lapse rates between 7-8 C/Km, high ELs, strong shear...large to very large hail is possible with initial development. A damaging wind threat may then emerge as storms grow upscale.

The curved nature of the hodograph as well as rich low-level moisture may allow for a tornado risk, but this could be mitigated by fast upscale growth and the strength of the front. Guidance shows the cold front surging south quickly, which may undercut convection causing storms to become elevated. Unlike the previous system, this does not appear as clear cut, and certainly bears watching.

Lastly, a flooding risk is also present as storm motions allow for training along the west-east oriented front. A few pockets of 1 to 2 inches of rainfall is likely, with locally higher amounts possible.

FRIDAY ONWARD

Another significant cool-down is likely by Friday with highs back into the 40s/50s. As with previous iterations of this pattern, the cool-down is short-lived and a warming trend begins again over the weekend. Temperatures may once again push into the 70s early next week. Furthermore, ensemble guidance is hinting at an active weather pattern taking shape during the first week of April.

AVIATION (12Z TAF Issuance)

Issued at 630 AM EDT Wed Mar 25 2026

Impacts:

- Southwest wind gusts up to 20-25 kts Wednesday and Thursday afternoon

- Showers and thunderstorms possible between 05-12Z Thursday

Discussion:

VFR conditions continue as the Ohio Valley will remain under the influence of high pressure through today. Mid and high level clouds will drift across the region at times. Light E/SE winds are expected this morning with an increase in speeds through the day. Winds gradually become southwesterly later this morning. Periodic gusts up to 20kts are possible during the afternoon.

Thunderstorms are also possible between 03-11Z Thursday, but confidence remains limited at this time. Confidence was high enough to include a PROB30 for storms at most sites though and this will be refined in future updates. Thunderstorm activity ends early Thursday morning. Gusty SW winds return Thursday afternoon.

IND WATCHES/WARNINGS/ADVISORIES

None.