textproduct: Indianapolis

KEY MESSAGES

- A mix of snow and sleet is expected tonight into tomorrow morning.

- Highest snow accumulations of up to 2 inches are expected south of the I-70 corridor, with all areas south of a Crawfordsville to New Castle line expected to get at least 0.5 inches.

- A light glaze of freezing rain is possible over southern portions of the area, but confidence in ice accumulation is low at this time.

- Warming trend and daily rain chances for much of the week into the weekend. Heavy rainfall potential at times may lead to flooding concerns.

FORECAST UPDATE

Issued at 921 AM EST Sun Mar 1 2026

Chilly start this morning with cool northerly flow across the region as a frontal boundary has settled across the Tennessee Valley. Skies were mainly sunny south of I-70 with a broad stratus deck further north. 14Z temperatures ranged form the upper 20s to the mid 30s.

The presence of the stratus deck will be the primary focus for the update and the impacts that may have on temperatures into the afternoon. With N/NE flow present through the boundary layer...the stratus has been making slow but steady progress southward and has just about encompassed the Indy metro. Anticipate further expansion southward across the area through midday with a gradual mixing out of the deck into the afternoon as the low level inversion weakens and drier air filter down into the near surface layer. As the lower clouds mix out however...mid and high level clouds will be arriving from the west in advance of a disturbance that will bring a wintry mix of precipitation tonight into early Monday.

Have left high temperatures alone for now but there is potential that highs may need to be nudged down a couple degrees across the northern half of the forecast depending on how long the stratus lingers. Highs will range from the upper 30s in northeast counties to the upper 40s in the lower Wabash Valley.

SHORT TERM (Today and tonight)

Issued at 307 AM EST Sun Mar 1 2026

Central Indiana will begin a rather active weather pattern late Sunday through a majority of next week, with a succession of weak to moderate waves and strong moisture return.

The first of which will arrive tonight. This initial disturbance will be much different that the rest, with a majority of the dynamics situated in the lowest 5km of the atmosphere, and a very dry antecedent airmass that will likely push wetbulb temperatures below freezing across most of central Indiana during precipitation onset. The rest of the systems will largely have upper level support and much greater moisture attached leading to greater QPF, but wetbulb temperatures consistently well above freezing (talked about further in the long term section).

Currently, we have a lingering quasi-stationary boundary along the Ohio River valley that is leading to modest deformation and keeping a defined baroclinic zone over the region as well. This is creating isolated to scattered showers early this morning, but as low level pressure depletion increases upstream throughout the day, this stationary front will strengthen leading to greater lift and widespread precipitation.

Counteracting this is a rather strong surface high over the Great Lakes region, and the subsidence on its periphery is creating very dry near surface conditions. Initially this should lead to near seasonal temperatures prior to precipitation, with the dry low levels allowing for fairly efficient warming, but a consistent cloud layer curtailing afternoon highs, topping out in the low to mid 40s.

By this evening, the strengthening of the LLJ ahead of the aforementioned pressure depletion will create a layer of strong lift between 850-600mb with mid level precipitation processes beginning by 02-04Z. With the lower 3km in the atmosphere initially having 15-25 degree dew point depressions, any precipitation should initially fall as flurries or sprinkles for the first few hours until the lower level saturates enough for accumulation to occur.

While this is happening, a warm nose will develop within the LLJ upstream, reaching southern portions of central Indiana after 06Z. Wet bulb temperatures over a majority of central Indiana (all but far SW portions) will likely be low enough for all precipitation types to be frozen, but within the warm nose a corridor of sleet and potentially freezing rain will be likely. This warm nose will quickly advance eastward, with precipitation types transitioning to all snow in the pre-dawn hours before rates drop significantly near and after dawn. Temperatures will increase slightly after dawn as well, with any lingering precipitation along the remnant stationary boundary likely falling as all rain the rest of Monday

As far as totals, this system will be VERY tricky given the variety of precipitation types, and therefore SLRs, a very strong high to the north, and a narrow corridor of forcing. 00Z High resolution ensemble guidance is also still varied in QPF axis by around 50 miles leading to even further uncertainty as of this forecast issuance. That said, there seems to be two consistencies: There will be a corridor of mixed precipitation within the warm nose, and there will be a sharp cutoff in accumulation north of I-70. The specifics of this are still being unraveled, and therefor any location specific snowfall or ice accumulation forecasts may change quite a bit over the next 24 hours. For now the forecast is for 0.5-2.0" of snow between a southern line of Vincennes to Salem and a northern Line of Crawfordsville to New Castle. Southern portions of this corridor are likely to see higher overall QPF, but much lower SLRs and a wintry mix (primarily sleet). Depending on the depth of the warm nose these is also a chance for a light glaze of ice accumulation as well, but confidence in this is low at this time.

LONG TERM (Monday through Saturday)

Issued at 307 AM EST Sun Mar 1 2026

The long term period will be active as a large troughing pattern sets up over the west with high pressure over the Atlantic and placing our region mostly under SW flow.

The pattern change will bring ample moisture and warm air advection to the region. Expect a warming trend with high maxing out near 70 late week. A generally west-east boundary will set up across or near the area, along which multiple passing systems bringing daily chances for rain that could be heavy at times. The first system will be a low tracking from the central plains to the Ohio Valley/ Great Lakes mid to late week. Another system or two should bring even more rain to central Indiana this weekend. There remain discrepancies between models on the timing, location, and details of each of these systems yet there is agreement in the signal for impactful rainfall totals for the period. By the end of next weekend, we could see widespread multiple inches of rainfall totals as anomalously high PWATs for this time of year are expected. This will likely lead to at least river flooding but can't rule out more general flooding concerns for central Indiana. Now is the time to prepare for floods: make sure storm drains and gutters are clear, check that sump pumps are working properly, and remember to never drive into flood waters.

AVIATION (18Z TAF Issuance)

Issued at 1202 PM EST Sun Mar 1 2026

Impacts:

- MVFR stratus early this afternoon then gradually mixing out - Wintry precipitation impacting KBMG/KHUF/KIND after 05-06Z with visibility restrictions - Primarily light snow briefly mixing with sleet at KHUF and KIND with more mixed precipitation at KBMG - MVFR stratus returning predawn into the day Monday at all but KLAF

Discussion:

Stratus remains fairly prevalent over the terminals early this afternoon but recent satellite trends suggest the deck is beginning to mix out as drier air is drawn into the boundary layer. The stratus will largely diminish by mid afternoon with a predominant mid level deck settling up through the evening.

A disturbance will move across the region late tonight and Monday morning bringing a brief period of light wintry precipitation. At this point...KBMG and KHUF will be impacted the most with lesser impacts at KIND. Low level thermal analysis suggest primarily light snow at KHUF and KIND with the potential for some sleet mixing in...while there could be a mixture of rain...sleet and snow at KBMG. Visibilities will drop to 2-4SM particularly within any heavier precipitation bands. Precipitation will depart quickly Monday morning but MVFR stratus will settle back in across all bu north central Indiana.

Northeast winds at 10-15kts through this evening will veer to easterly by Monday morning.

IND WATCHES/WARNINGS/ADVISORIES

None.