textproduct: Indianapolis

KEY MESSAGES

- Highs in the 50s today with a warming trend through Thursday.

- Showers and thunderstorms possible Thursday and Thursday Night, some of which may be severe.

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

FORECAST UPDATE

Issued at 910 AM EDT Tue Mar 24 2026

Forecast is in good shape this morning, so only made some tweaks to match current trends seen on satellite and in hourly observations.

High pressure will continue to provide quiet and seasonable weather today.

SHORT TERM (Today and tonight)

Issued at 304 AM EDT Tue Mar 24 2026

Expect quiet weather conditions through the period as surface high pressure remains in control. Relatively favorable radiational cooling aided by weakening winds and scattered high clouds has allowed for temperatures to steadily fall overnight. Current temperatures in the upper 20s to mid 30s have cooled slightly quicker than anticipated so slight adjustments were made. High resolution guidance was incorporated to drop lows a few degrees. Expect lows to generally range from the mid 20s to low 30s this morning.

The surface high will progressively shift eastward today into tonight leading to winds becoming more S/SE compared to ENE flow at this time. Wind speeds are likely going to remain light under 10 kts across central Indiana. Northwest flow remains aloft, but subtle warm air advection beneath this and partly cloudy skies is expected to promote warming temperatures. Look for highs to warm well into the 50s.

Diurnal mixing into a very dry airmass just above the surface should also support min RH values around 25 to 30 percent this afternoon. Light winds and recent rainfall will tend to limit fire weather concerns for the moment though. Some increase in clouds appears likely towards the early evening and overnight hours as a weak upper wave moves through. No precipitation is expected from the disturbance due to a dry airmass still in place in the lower levels.

LONG TERM (Wednesday through Monday)

Issued at 304 AM EDT Tue Mar 24 2026

Anomalous ridging out west combined with low-amplitude troughing over the northeast will promote progressive northwesterly flow aloft across the Midwest. This pattern has allowed for variable conditions with periods of above-normal warmth interrupted by brief but potent cold fronts. This is expected to continue, as the cold air mass behind Sunday's strong front will already be in the process of moderating as of this writing.

High pressure slides east of the region today, allowing winds to become southerly with gradual warm air advection taking hold. By Wednesday, guidance shows a subtle vort max approaching from the west. This feature causes surface MSLP gradient to tighten as well as allowing a potent low-level jet to begin forming. Winds also become more southwesterly in nature which allows warm air advection to accelerate. Highs may climb into the upper 60s/low 70s Wednesday afternoon.

MIDWEEK THUNDERSTORM POTENTIAL

The low-level jet reaches peak intensity late Wednesday night into Thursday. The aforementioned vort max, combined with isentropic lift from warm air advection, and surface convergence at the nose of the LLJ...all point towards an area of broad lift arriving late Wednesday night. Guidance has come into better agreement showing isolated convection developing before sunrise Thursday. Instability appears low, which would limit updraft intensity...but shear is plentiful and long straight hodographs suggest a non-zero hail risk.

The pattern then repeats again with another strong cold front modeled to drop south late Thursday. Temperatures may once again approach record levels with highs pushing into the 80s across the region before the front arrives. The synoptic set up is actually very similar to yesterday. Strong warm/moist advection, broad synoptic-scale forcing, with moderate to high levels of shear and instability. This all points towards another round of showers and thunderstorms, with the potential for severe weather, late Thursday.

Guidance is already trending towards anafrontal convective development, with elevated storms intensifying behind a shallow but strong cold front surging southward. Details still need to be ironed out, including timing and how steep mid/upper-level lapse rates are which will determine storm intensity behind the front. Shear is plentiful, and given the elevated nature of modeled convection it would appear large hail is again the primary hazard.

THIS WEEKEND 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 60s/70s early next week.

AVIATION (12Z TAF Issuance)

Issued at 546 AM EDT Tue Mar 24 2026

Impacts:

- Winds shifting from easterly to S/SE today

Discussion:

VFR conditions are expected through the period with high clouds passing overhead at times. Winds are expected to veer today from easterly to S/SE. Sustained winds will remain below 10kt during the period.

IND WATCHES/WARNINGS/ADVISORIES

None.