textproduct: Indianapolis

KEY MESSAGES

- Thunderstorms, some possibly severe across far southern portions of central Indiana late this afternoon/early evening.

- Storm chances return Monday along with much warmer than normal temperatures Sunday through Tuesday with highs in the 80s.

- A frontal passage Tuesday into early Wednesday will bring additional chances of severe storms along with cooler and drier weather for the later part of next week.

DISCUSSION (This evening through Saturday)

Issued at 355 PM EDT Sat May 16 2026

Tonight....

Convection tied to the MCV will continue to move eastward before gradually diminish late evening. Threat for isolated severe winds/hail will be possible through 02Z /10 PM EDT/. Overnight, a slowly NE moving warm front combined with a 30-40 kt low level jet will likely support renewed elevated convective development after 05Z. PoPs have been raised a category to account for this increasing potential.

Sunday/Sunday Night...

Scattered TS will come to an end early Sunday (before 15Z) as the warm front lifts northward. Gusty S-SW winds will develop by late morning lasting into the afternoon owing to an increasing surface pressure gradient and modest low level flow in the boundary layer. High temps are expected to easily rise in the 80s area wide by afternoon with 850 temps around 17-18C. Combined with dewpoints in the lwo-mid 60s, heat indices are expected to be in the mid-upper 80s, close to the warmest apparent temps since late March. Skies are expected to be mostly clear Sunday and Sunday night with just afternoon cumulus and increasing cirrus overnight from Plains thunderstorm activity.

Monday/Monday Night...

Model consensus is that a relatively innocuous mid level vort max/lead shortwave trough associated with the southern jetstream /per sat off of Baja CA coast/ will move NE across Mexico and TX and into the Ozarks/Mid MS valley by Monday afternoon. With weak inhibition and moderate instability /MLCAPE around 2000 J/KG/ noted on forecast soundings, scattered TS are expected for form just west of central IN during the mid-late afternoon. Weak 0-6 km shear will limit threat for more significant severe threat, but moderate anvil venting and low level flow may support a low end hail/damaging wind threat if activity can become organized linearly. This activity is expected to weaken overnight Monday night with loss of heating amidst weak forcing. High temps on Monday are once again expected to be well above normal, despite some increase in clouds cover with 80s areawide.

Tuesday/Tuesday Night...

A cold front will push southward across the plains and upper Midwest, however timing of the front is somewhat uncertain 3 days out. Thunderstorm activity is expected to be numerous along the front with deep layer forcing and moderate instability /CAPE 2000-3000 J/KG/. Convective mode is expected to be fairly linear convective with damaging winds the primary threat, per the SPC Day 4 slight risk outlook. In addition, locally heavy rainfall may lead to minor flooding.

Wednesday into Saturday....

The primary cold front is expected to push across central Indiana early on Wednesday. In the wake of the front, cooler and drier air is expected through Thursday. Thereafter, there is some disagreement with the strength of the shortwave trough moving into the Rockies and Plains and the consequent timing and coverage of additional precip development moving back into central Indiana going into the Memorial Day weekend/500 festivities. High temps are expected to be below normal Wed and Thursday rising to near normal by Saturday.

AVIATION (00Z TAF Issuance)

Issued at 744 PM EDT Sat May 16 2026

Impacts:

- Low end MVFR ceilings with possible -TSRA early Sunday morning.

- South gusts around 20kt Sunday afternoon

Discussion:

Thunderstorms this evening will be confined to far southern portions of central Indiana in the vicinity of an outflow boundary/stationary front. Overnight, this front will become a warm front while moving northward. Moist ground and light winds will lead to a reduction in VIS to MVFR as well as lowering ceilings into MVFR developing beneath and inversion. Greater reduced vis/fog as advertised by some models is not expected given the cirrus deck that will be prevalent overnight.

Associated with the warm frontal passage, there will be a chance of scattered TS. Have maintained a PROB30 for early Sunday morning from 07-11Z to account for this potential.

As the warm front lifts northward, skies will clear with gust winds out of the S-SW (180-190 deg) by late morning through the late afternoon with VFR conditions.

IND WATCHES/WARNINGS/ADVISORIES

None.