textproduct: Indianapolis

KEY MESSAGES

- Showers and a few t-storms tonight, gusty winds possible

- Dry and seasonable Wednesday through Friday

- Warming trend this weekend and into next week with daily storm chances. Potential for first 90 degree day of the year next week.

DISCUSSION (This evening through Tuesday)

Issued at 258 PM EDT Tue May 12 2026

Tonight through Thursday Morning.

Dry and warmer weather this afternoon and evening across Central Indiana ahead of an approaching cold front for tonight. Satellite and radar imagery show a line of showers and a few thunderstorms storms along a front extending from the UP of Michigan southwestward into Iowa. The environment ahead of this front is very dry with surface dew point depressions of 25-30 degrees due to afternoon mixing. This dry air will significantly limit the overall severe and heavy rainfall threat tonight; however CAMs do show modest moisture advection into the region as the low level jet ramps up after sunset and mixing wanes. Due to such dry air in the lower levels and stepper 0-3km lapse rates,suggests a marginal wind threat may exist with storms as they approach NW portions of Central Indiana in the 10-11pm timeframe. Instability is marginal at best with most CAMs showing 200-400 J/kg of CAPE for storms to tap into. Best chance for a strong storm or wind gust above 50 mph will likely be in the NW quadrant of Central Indiana, with the severe and thunder threat waning as convection encounters drier and more stable air to the southeast.

Dry air quickly advects in behind the cold front as high pressure drops southeast into the Plains. Lingering low clouds may persist into the early to mid morning hours before lifting during the afternoon and breaking up. The NW pressure gradient behind the front remains tight enough to support gusty winds into tomorrow especially with steeper low level lapse rates and mixing during the afternoon. Some hi-res guidance suggests wind gusts of 25-30 mph during peak heating of the day tomorrow, a little over what the NBM depicts, which seems very reasonable. Temperatures may struggle to get into the lower 60s tomorrow north of I-70 as a fairly cold airmass for this time of year advects in aloft. Deeper mixing should help temperatures recover during the afternoon, yet still remain below normal for mid May with winds making it feel even colder. Expect a good N-S temperature gradient across the state tomorrow afternoon with upper 50s to low 60s across the north and low 70s in SW and Southern Indiana.

High pressure becomes centered overhead late Wednesday night into Thursday, setting the stage for another cold night across Central Indiana due to radiational cooling. With such a cool and dry airmass in place (dew points in the mid 30s), some locations in North Central Indiana may dip down into the mid to upper 30s. For now the forecast keeps lows at or above 39 degrees, but may need to be adjusted down a few degrees in more rural locations. Widespread frost is not expected, but still possible in rural locations north of I-70.

Thursday through Early Next Week.

A prolonged period of increasingly warm weather is expected late this week and through the early weekend, but with an increase in daily storm chances as well. Surface high pressure will firmly establish itself over the Ohio Valley on Thursday and Friday, promoting mostly sunny skies, light winds, and highly favorable outdoor conditions.

By the weekend, a significant shift in the upper-level atmospheric pattern takes place with high confidence as both deterministic models and ensemble clusters exhibit strong consensus regarding the amplification of a prominent upper-level ridge of high pressure across the eastern half of the United States. Strong warm air advection on the backside of the departing surface high will draw seasonably warm air into Indiana. High temperatures are projected to climb from the low 70s on Friday into the mid to upper 80s by Saturday through Monday, which is well above normal for the middle of May.

Daily storm chances will exist Friday into early next week as individual disturbances set up along a quasi-warm frontal feature stretching across the Plains and Great Lakes. While low confidence exists in exact timing of placement of each wave, this type of warm/hot and humid pattern does support daily storm chances with a few severe storms not out of the question. Keeping PoPs at or under 50% for now and will adjust them accordingly as confidence increases in the finer details. Not expecting a washout of a weekend, but confidence is increasing in storms being in the vicinity .

AVIATION (18Z TAF Issuance)

Issued at 227 PM EDT Tue May 12 2026

Impacts:

- Wind shift from SW to NW through the period - SHRA late evening to overnight for most sites - Southwesterly gusts up to 25kts through early morning

Discussion:

VFR conditions expected through much of the TAF period. Brief lowered ceilings and visibilities to MVFR are possible as rain moves through, but not enough to include in TAFs. Earliest chances for rainfall look to be around 01Z at LAF with chances increasing through 04Z. There may also be a few rumbles of thunder, but confidence is too low to mention in the TAF. In addition to the rain, can't rule out a chance for sporadic LLWS as a strengthening LLJ moves overhead. More so expecting gusts to 25 kt through the early overnight hours. Rain chances then look to end towards 09Z. Additional gusts to 25 kt likely tomorrow afternoon as well, this time from the NW.

IND WATCHES/WARNINGS/ADVISORIES

None.