textproduct: Indianapolis

KEY MESSAGES

- Cooler and rainy today with isolated thunderstorms possible.

- Heavy rain could result in localized flooding of low lying and agricultural areas.

- Largely below normal temperatures this upcoming week, with multiple chances for more rain on Friday Night and again on Sunday.

DISCUSSION (Today through Monday)

Issued at 219 AM EDT Tue May 5 2026

Surface analysis early this morning shows low pressure over MI, with a cold front extending SW to nrn IL and to Central MO. Radar shows areas of showers and thunderstorms along and ahead of the front, stretching across Central Indiana to central IL. Aloft, water vapor showed deep low pressure over Ontario, providing cyclonic flow across the upper midwest, but mainly a zonal flow was in place across Indiana. A short wave pivoting around the upper flow pushing through the northern plains. Water vapor shows Pacific moisture streaming across the Rockies into the plains toward Indiana. A more tropical plume of moisture was found streaming across Baja California and Texas toward the Ohio valley. These features were providing ample moisture for showers and storms ahead of the front and upper short wave.

Today and Tonight...

Models show the cold front will slowly sag southward across Central Indiana through the course of the day. More showers and storms are expected through the day along and in the wake of the front, as the upper short wave continues to approach from the northwest. The previously discussed flow of upper moisture with embedded disturbances are then expected pass across central Indiana today and into the evening. HRRR suggest several waves of showers through tonight. Forecast soundings through today and into tonight show deep saturation, with pwats over one inch. Better drying and subsidence within the column does not appear to arrive until Wednesday. Thus will use near 100 pops for today and tonight. Although soundings do not suggest a favorable column for convection, an isolated rumble of thunder cannot be ruled out.

Given our expected rain today and the arrival or north winds, expect steady state temperatures today in the mid 50s. Lows tonight will fall to the mid 40s.

Given all this rain, flooding of low lying and agricultural areas will be possible, flood advisories along with a few areal flood warning may occur later today and tonight.

Wednesday through Thursday...

Cooler but drier weather will arrive for Wednesday and Thursday. Models suggest surface high pressure over the northern plains states will build SE across Indiana and into the Ohio valley, while the cold front sags farther southeast. The steady upper flow of moisture is also shifted farther south, across the Tennessee Valley and the Carolinas. Forecast soundings across Indiana during this time dry out considerably, suggesting subsidence and drying. Some afternoon CU will be possible, resulting in partly sunny skies on Wednesday and bit more sunshine on Thursday. Cool northwest flow will continue to keep temperatures below normals, with highs in the 60s.

Friday through Monday...

Broad upper cyclonic flow will remain in place across Indiana and the northeastern quadrant of the United States through the weekend and into Monday. Models suggest a pair of short waves pushing across Indiana within the upper flow on Friday into Saturday and again on Sunday afternoon into Sunday Night. Within the lower levels a cold front is suggested to pass on Friday night into Saturday, and another low pressure system is suggested to pass on Sunday. Surface high pressure will then arrive on Monday. Forecast sounds show most favorable conditions for precip will be on Friday and Sunday as the surface and upper features pass. Still due to timing adjustments between now and then larger windows of pops will be used.

No intrusions of warm air are expected this period as the strong upper low to the north continues to keep mainly a NW flow of cooler, Canadian air across central Indiana. This will keep temperatures at or below seasonal normals.

AVIATION (06Z TAF Issuance)

Issued at 1224 AM EDT Tue May 5 2026

Impacts:

- VFR deteriorating to MVFR overnight in showers and thunderstorms. - MVFR or worse much of Tuesday in rain showers with isolated thunder.

Discussion:

Radar shows an area of convection over NW Indiana and Central IL poised to push across Central Indiana over the next 6 hours. Ongoing TSRA window will be best between 06Z and 09Z as HRRR suggests the convection organizes a bit more into a line, with a cold pool pushing the storms south across the TAF sites. Bases across the area are VFR, but brief MVFR cigs will be possible overnight in a few storms.

On Tuesday a cold front will slowly sag southward across the TAF sites. As this occurs winds will shift to the north and cigs are expected to fall to the MVFR levels. HRRR suggests several waves of rain showers to pass through the day on Tuesday, and predominate rain with mvfr conditions or worse is expected. Isolated thunder will also be possible.

IND WATCHES/WARNINGS/ADVISORIES

None.