textproduct: Indianapolis

KEY MESSAGES

- Isolated thunderstorms this morning, localized large hail threat

- Scattered strong to severe storms likely this afternoon into the evening

- Primary threats damaging winds/isolated tornadoes with afternoon storms

- Colder for the weekend, with scattered light snow possible Sunday

SHORT TERM (Today and tonight)

Issued at 315 AM EST Thu Feb 19 2026

A trough over the western US will eject eastward into the Plains this morning, amplifying as it does so. Surface cyclogenesis is occurring in the lee of the Rockies over western Kansas. The resulting low is expected to intensify as it moves east-northeast, ending up roughly over Chicago by 00z.

Strong southwesterly flow extends from New Mexico northeast into the Great Lakes, as evidenced by fast-moving cirrus streaming over the region. These clouds also signal broad lift arriving ahead of the western trough. Low-level flow has once again become southerly in response to the developing low to our west. Dew points have crept upwards through the night, hovering in the 40s to near 50 at IND.

MORNING CONVECTION

ACARS soundings out of IND show steep mid-level lapse rates through about 450mb. With low-level moisture increasing, this has lead to elevated instability between 300-500 J/Kg. Guidance shows overall instability increasing through the morning hours as warm moist air continues to advect northward. ACARS soundings also show long straight hodographs with nearly 50kt of effective shear.

Convection has already begun firing up over eastern IL and into Warren County as of 07z. Radar imagery shows cells splitting, indicative of the influence of strong unidirectional shear. As such, the primary hazard through the morning hours will be large hail. However, ACARS soundings show substantial dry air in the low/mid- levels, and combined with the steep lapse rates, a few marginally severe wind gusts cannot be ruled out.

Convective activity will likely focus on a developing warm front, which extends across central IL and into northern IN. Cells that fire up along this front may take on a deviant rightward motion, which may allow activity to persist over our northern counties through the morning hours.

AFTERNOON SEVERE POTENTIAL

Our attention then turns to the next round of convective potential associated with the developing low. Guidance continues to hone in on convective development over Missouri later this morning, coincident with strong mid-level vorticity advection and surface convergence ahead of the low center. This convection then races northeastward into Illinois and eventually Indiana, strengthening as surface heating increases available instability. Overall instability may level off, however, as strong mid-level warming causes lapse rates to relax.

In terms of potential hazards, a developing low-level jet beneath the strong southwesterly flow aloft should enhance curvature within the low-level hodograph (resulting in strong 0-1km shear between 15- 30kt / 150-250 m2/s2 SRH). Ongoing warm moist advection will bring T/Td into the 60s/50s respectively, allowing for steep low-level lapse rates and rich boundary layer instability. As such, the potential for tornadoes exists, especially with any right-deviant supercell. A possible mitigating factor is residual low/mid-level dry air, which may cause storms to become cold pool dominant. Southerly surface winds are not expected to be particularly strong, which may limit how effectively this process can be overcome.

The aforementioned low/mid-level dry air may allow for severe wind gusts, especially as the low-level jet intensifies and low- level lapse rates steepen. This may become the primary hazard during the afternoon hours. The hail threat likely decreases with time as mid-level warming lowers ELs causing storms to become shallow in nature. Initial cells, especially supercells, will pose the greatest hail threat.

TONIGHT

Once the system's cold front / dry line passes through, the convective threat comes to an end. FROPA occurs between 03z-06z from west to east. Rapid clearing is anticipated with clear to partly cloudy skies expected for a time overnight tonight.

Guidance is beginning to consolidate around the idea of strong synoptic-scale winds on the back side of the low as it passes to our north. CAMs in particular are quite aggressive, with gusts between 40- 45 knots. Winds likely increase from 06z onward, especially further north closer to the low itself. A Wind Advisory may need to be issued at some point, depending on the strength of the low and the MSLP gradient surrounding it.

LONG TERM (Friday through Wednesday)

Issued at 315 AM EST Thu Feb 19 2026

Friday Through Sunday.

The synoptic pattern transitions sharply on Friday as the primary upper-level low translates toward the Eastern Great Lakes. Central Indiana will be positioned within a zone of strong CAA as 850mb temperatures plummet below zero. A tight surface pressure gradient will persist through Friday evening, maintaining brisk westerly winds with gusts frequently reaching the 30-40 mph range with the boundary layer around 4kft deep. This mixing will limit high temperatures to the mid-40s, a significant departure from the record- challenging warmth experienced earlier in the week.

Focus then shifts to a quick moving upper level low over the Great Lakes that is expected to dive to the southeast, putting central Indiana in a favorable position for cyclonic flow and steepening low- level lapse rates. While deep-layer moisture is progged to be meager, the cold air over the relatively warmer waters of Lake Michigan could support a period of lake-enhanced snow showers. Current ensemble probabilities favor the northeastern forecast area for the highest frequency of these showers, with the potential for a dusting to half an inch of accumulation.

Monday Through Wednesday.

By early next week, aforementioned low will transition into a more traditional Nor'easter, allowing for a gradual transition to a more zonal flow across the Ohio Valley. High pressure at the surface will slide through the area, leading to a brief period of airmass recovery and dry conditions. However, the pattern remains progressive as a weaker, fast-moving shortwave approaches by Wednesday. Forecast uncertainty for the mid-week period centers on the depth of the return flow and whether enough moisture will recover before the arrival of the next cold front. Current projections suggest a return to high temperatures near 50 degrees with low-end chances for rain.

AVIATION (12Z TAF Issuance)

Issued at 628 AM EST Thu Feb 19 2026

Impacts:

- IFR, or worse, conditions this morning with fog - Scattered thunderstorms from the mid afternoon to early evening - Gusty SW winds possible Thursday night, gusts between 20-30kt.

Discussion:

Moist southerly flow has brought fog to most of central Indiana as of 11z, with some locally dense fog at times. Fog may continue well into the morning hours since it is driven by advection. IFR conditions, or worse, are likely this morning. Conditions will improve late morning into the early afternoon as stronger S/SE surface flow develops.

The approach of strong low pressure from the west with the warm front in the area will set the stage for convective development over Illinois during the first half of Thursday afternoon...spreading east into central Indiana mid afternoon into the evening. IFR and lower restrictions will accompany the heaviest convection.

The aforementioned system's cold front passes through around 02z- 04z, ending the threat of convection. Clearing skies with a return to VFR conditions is expected. Guidance shows strengthening winds, potentially gusty, in the post-front environment. We've included gusts up to 30kt for now, but winds could potentially be higher especially further north and west.

IND WATCHES/WARNINGS/ADVISORIES

None.