textproduct: Indianapolis

KEY MESSAGES

- Above normal temperatures through the weekend, with near record highs on Sunday

- Showers and thunderstorms possible on Sunday, a few strong to severe storms cannot be ruled out.

- Mostly dry and warmer than average conditions expected next week.

SHORT TERM (This evening through Saturday)

Issued at 221 PM EDT Fri Mar 20 2026

Surface analysis early this afternoon shows broad but weak low pressure over SE MI while much stronger high pressure was found over the southeastern states. This was resulting in westerly surface flow across central Indiana along with a moderate pressure gradient. A cold front trailed from the low, stretching across southern MI, southern WI to IA. Aloft, strong high pressure and ridging was found over the western CONUS, and this was resulting in lee side NW flow spilling across the northern plains and into the Ohio Valley. Ridge riding clouds were streaming across Indiana within this northwest flow aloft. These high clouds were found in the water vapor imagery as Pacific moisture. Temperatures were in the upper 60s early this afternoon and should reach the lower and middle 70s by late afternoon.

Tonight and Saturday...

The strong ridging over the western CONUS found in the upper pattern is expected to flatten tonight and on Saturday, however the quick flow over this ridge will keep any cold air intrusions away, along with keeping a flow of mild, Pacific air flowing across the northern parts of the United States and spilling SE toward the Ohio Valley. Meanwhile within the lower levels the cold front to our northwest is suggested to push across our area this evening as the low pressure system to the NE Pushes toward New England. Forecast soundings while this front passes shows limited lower and mid level moisture, and no precipitation is found along the front. Thus will trend toward a dry frontal passage with just some passing high clouds through the night. As winds become northerly thus evening cold air advection is minimal as only a glancing blwo of cold air passes mainly across the Great Lakes. Thus expect lows mainly in the 40s.

On Saturday, high pressure will quickly arrive in the eastern Great Lakes, once again allowing for the return of warm southerly lower level flow. Again, forecast soundings remain dry, with subsidence as the predominate feature. Thus only some high passing clouds within the quick flow aloft will be expected. Highs should once again reach the lower 70s.

LONG TERM (Saturday night through Friday)

Issued at 221 PM EDT Fri Mar 20 2026

Primary focus for the long term is on Sunday's potential for near record high temperatures, gusty winds, and thunderstorms ahead of an approaching cold front - including a fairly conditional threat for severe storms.

Blended guidance continues to suggest high temperatures will make the 80s across a significant portion of central Indiana on Sunday. 82 is the record for the date at Indianapolis, set in 1907. Potential for afternoon convection and slightly earlier arrival of the front introduces uncertainty here.

Additionally, steep low level lapse rates and a fairly deeply mixed boundary layer will promote momentum transfer from stronger flow aloft. Wind gusts midday into Sunday afternoon outside of any storm activity will likely approach or even exceed 30 MPH at times.

Though upper level support will be modest, good convergence and some low level moisture pooling along the approaching boundary may allow for thunderstorm development in the afternoon and evening. A midlevel inversion at the base of an elevated mixed layer, as well as PBL mixing promoting some near surface drying with time, call into question whether deep, moist convection will occur, or if it does, the degree of coverage, but any storms that form and persist will have access to plentiful deep layer shear, and would likely become severe. Instability profiles are likely to be concentrated in the midlevels in an environment with midlevel lapse rates approaching 8 C/km, tending toward a large and locally very large hail threat, particularly early prior to any upscale growth occurring. A damaging wind threat would be present as well given significant midlevel dry air, especially as storms coalesce with time.

Dry and substantially cooler conditions will return for the early to mid portion of the work week in the wake of the front, though temperatures would likely only return back to near to a bit above seasonal normals.

The next opportunity for precipitation looks to hold off until late in the week as a stronger area of low pressure organizes to the northwest, though significant guidance differences exist here.

AVIATION (18Z TAF Issuance)

Issued at 1233 PM EDT Fri Mar 20 2026

Impacts:

- VFR Conditions this TAF period.

Discussion:

VFR conditions will continue through the TAF period. Low pressure will drag a cold front across Central Indiana this evening, allowing winds to shift from the southwest to north. Wind gusts this afternoon to around 25-30 knts will be possible ahead of the front due to mixing and a moderate pressure gradient across Central Indiana.

Forecast soundings through the period remain dry within the mid and lower levels. Thus only high passing clouds will be expected this TAF period due to the northwest flow aloft. Winds will subside to around 5 knts in the wake of the front.

IND WATCHES/WARNINGS/ADVISORIES

None.