textproduct: Indianapolis

KEY MESSAGES

- Wind chills in the teens tonight, Thursday night, and Friday night

- Threat continues for accumulating snow Saturday before a gradual changeover to rain by early Sunday

- Much colder air to open December with additional opportunities for wintry weather

FORECAST UPDATE

Issued at 857 PM EST Wed Nov 26 2025

The forecast remains in good shape with only slight adjustments needed. Latest surface analysis depicts a large broad low pressure system over the Great Lakes Region. This system will continue to gradually depart resulting in a weakening MSLP gradient. This along with a slowly stabilizing PBL should help strong winds taper off late overnight. Current observations suggest winds have relaxed slightly from earlier today, but wind gusts are still around 25-35 mph. These winds have helped to limit diurnal cooling. Look for lows in the 20s tonight.

Satellite imagery shows much of central Indiana has cleared out due to drier air filtering in. However, guidance suggest additional low clouds may develop late tonight. Forecast soundings depict strengthening subsidence aloft which will likely be the main factor aiding in the development of some low clouds.

SHORT TERM (This evening through Thursday)

Issued at 154 PM EST Wed Nov 26 2025

Observational data and satellite imagery show a strengthening surface low over northern Lake Michigan as of 1pm. A very tight MSLP gradient has developed around the low, and especially to its southwest. This has lead to strong winds with frequent gusts between 40 to 50 mph. Frequent wind gusts over 40 mph continue into this evening as boundary layer (PBL) mixing deepens allowing for greater downward momentum transfer of faster flow aloft. A Wind Advisory for gusts between 40-50mph remains in effect until 7pm.

Lapse rates within the PBL are also steepening, which has lead to enough shallow convective instability for flurries and light snow or graupel showers. With broad cyclonic flow in place, we expect precipitation to expand in coverage this afternoon. Surface temperatures are in the mid to upper 30s as of 1pm. Despite this, snow and graupel will be the primary precip type today. The reasons include the aforementioned steep lapse rates. Shallow convective forcing should allow for riming at times, which leads to graupel. It's also quite cold just above the surface so any snow/graupel will not need to fall through a significantly deep warm surface layer. Additionally, soundings and observations show the surface layer to be rather dry as well. This will help reduce the effects of melting through evaporational cooling.

Snow flurry/shower activity is expected to diminish quickly around sunset as instability is lost. Winds will likewise begin to die down as the PBL becomes more stable. However, a tight MSLP gradient remains in place and winds should continue to be on the breezy side through the night. Cold air advection continues through the night as well with temperatures falling into the low to mid 20s. Combined with the wind, wind chills may drop to as low as 10-15 degrees.

Thanksgiving

By tomorrow morning, the low over Lake Michigan will have moved eastward allowing the MSLP gradient to relax. Even with the downward trend, winds should remain elevated through the day. Frequent wind gusts between 20-30 mph appear likely. As mentioned above, wind chills are expected to be quite cold. Values as low as 10 degrees are possible through the morning hours. High temps top out around freezing for the northern half of our CWA, with mid to upper 30s further south.

Cloud cover looks to be less compared to today, with stratocumulus lifting northward overnight. Clouds may temporarily drop southward again during the day tomorrow before slowly dissipating overnight into Friday morning. Flurries are still possible Thursday but mainly downwind of Lake Michigan. This places only our far northeastern counties under any chance to see flurries on Thanksgiving.

LONG TERM (Thursday night through Wednesday)

Issued at 154 PM EST Wed Nov 26 2025

Thursday Night Through Saturday.

The main focus for the long term period will be tracking the potential for an accumulating snow Saturday. Ahead of the snow, the breezy winds Thursday will gradually relax during the overnight with winds generally in the 10-15 mph range, but as temperatures fall wind chills will remain in the teens through the day on Friday.

While many of the finer details remain uncertain on the Saturday system, the broader details are becoming a bit more clear. Synoptically, an upper level shortwave will push southeast out of the Northern Rockies with weak southeasterly surface flow just ahead of the arrival of the low. Confidence is increasing in the surface low track with broad model agreement in central Indiana remaining in the "warm" sector of the system as the low tracks from Missouri through Northern Illinois and Lake Michigan.

Where details are still more uncertain and impactful will be surface temperatures ahead of the arrival of precipitation and the impacts on precipitation type. Latest trends over the last 12 hours have trended back southward concerning the rain/snow line with generally cooler antecedent conditions. The GFS continues to look a bit unmeteorological with snow well into the warm sector and weaker WAA near precipitation onset and continuing until the early overnight. Confidence remains fairly high in snow being the initial precipitation type before stronger southerly flow advects warmer air into central Indiana through the night. This non-diurnal temperature curve will help to transition the snow to rain at some point during the night.

That being said, at least some travel impacts look likely during portions of the afternoon and evening hours Saturday with surface temperatures in the upper 20s to low 30s ahead of onset and no expected issues for the snow to stick as temperatures will be well below freezing in the days leading up to Saturday. It remains very uncertain on specific snowfall totals, but a reasonable expectation at this time looks to be 2-4 inches across north central Indiana with 1-2 towards I-70 and 0-1 in points to the south. There remains the potential for both higher amounts up to as much as 6 inches in the worst-case scenario, especially towards Lafayette. With the latest trends, the potential for the event being all rain looks increasingly unlikely. Much of the impacts will be over a 6-8 hour window beginning sometime in the late morning/early afternoon hours with impacts lessening towards midnight.

Sunday Through Wednesday.

Going into Sunday much cooler temperatures will quickly move in as the low moves into the Great Lakes and much colder air pushes in on the backside of the system. There will be at least some mid-level forcing on the backside of the system which will bring the potential for additional rain/snow chances through the day Sunday with some signs of lingering flurries into Monday. Temperatures will then remain below normal through Wednesday with another low-end chance for additional snow Monday night into Tuesday while areas to the south of central Indiana may see potential heavy rain.

AVIATION (06Z TAF Issuance)

Issued at 1236 AM EST Thu Nov 27 2025

Impacts:

- West-northwest winds sustained at 10-16KT, gusting to 20-27KT through late today

- Low chance for MVFR ceilings at KIND/KLAF 09Z-14Z this morning

Discussion:

Mainly VFR conditions expected to prevail over central Indiana terminals into early Friday...with generally lower-VFR stratus dragging down and east of the I-65 corridor early this morning, which may briefly drop to high-MVFR over KLAF/KIND through 14Z. No obstructions to visibility are anticipated through the period.

Winds will continue to be greatest impact, although flow overnight into Thanksgiving Day to be noticeably lower than yesterday. Headings will overall veer slightly within 270-300 degrees through the TAF period...at 10-16KT and gusting as high as 20-27KT...with overall lighter winds to the south/west. Winds to diminish significantly through late day, with lighter winds sustained under 10KT at most terminals after 00Z Friday.

IND WATCHES/WARNINGS/ADVISORIES

None.