textproduct: Indianapolis

KEY MESSAGES

- Increasing clouds today with small afternoon rain chances. Warmer.

- Milder but still largely below normal for the upcoming week, with multiple chances for rain; heavy rain possible at times.

DISCUSSION (Today through Saturday)

Issued at 217 AM EDT Sun May 3 2026

Surface analysis early this morning shows strong high pressure in place over southern IL and SW Indiana. GOES19 shows clear skies across Indiana. Dew points were dry and mainly in the low to mid 30s. Aloft, water vapor shows a deep upper low over Quebec, allowing cyclonic flow across the eastern half of the country. The result from this is cool NW flow spilling across Indiana from central Canada.

Today...

A quiet and cool weather day is in store for today. Due to the start of some warm air advection, High temperatures will be a bit warmer compared to the past few days. Minimal forcing is suggested to pass within the flow aloft, but the 850mb level does show strong warm air advection today. Time heights and forecast soundings react to this showing the arrival of mid clouds this afternoon. Furthermore convective temperatures appear to be reachable. HRRR suggest some late afternoon showers across the area. Thus will keep some low chance pops in the forecast, although any precipitation will be light. Look for highs in the mid 60s.

Tonight through Tuesday...

Daily chances for showers and thunderstorms will be in play starting tonight and continuing through Tuesday. The upper pattern is suggested to become nearly zonal. Deep low pressure will be well to the north over Ontario, while a tropical high is in place over the Gulf. This will result in a steady westerly flow with several quick moving waves poised to pass tonight through Tuesday. Within the lower levels, Monday in central Indiana looks to be spent within the warm sector ahead of an approaching cold front. SSW flow across the area on Monday will allow dew points to climb in to the 50s. Forecast soundings within the warm sector on Monday afternoon suggest a favorable set-up for storms with CAPE over 1200 J/KG, steep lapse rates and pwats over 1 inch. This will be a favorable set-up for thunderstorms. More rain looks in store for Tuesday as a cold front slowly moves across Indiana through the day while surface low pressure rides along the frontal boundary across Indiana. Here, forecast soundings show a deeply saturated column with pwats over 1.2 inches. Thus confidence for a wet couple of day to start the workweek is high. Given the expected clouds, rain and change in the airmass on Tuesday, much cooler temperatures will be expected then.

Tuesday Night through Saturday...

As the upper level support arrives late Tuesday through Wednesday, surface pressure falls across the southern Ohio Valley will likely reinforce lift across central Indiana through deformation leading to additional rain chances. Latest guidance is advancing this forcing quickly eastward, with QPF on Wednesday trending downward. Temperatures for Wednesday will be cooler with deep cloud cover and consistent troughing aloft; expect highs in the upper 50s to low 60s. Frosty conditions once again cannot be ruled out for Wednesday night with 850mb temperatures hovering just below freezing. That said, this will greatly depend on if clearing will occur as surface pressure increases.

To end the week, there will be a slight pattern change as the Bermuda high slides westward and the deep troughing over the eastern- half of Canada begins to flatten out. This will likely lead to more a more consistent pattern of near seasonal temperatures with brief periodic rain chances along quickly passing shortwaves. Timing of these waves is still widely varied amongst ensemble members.

As we head into the middle of the month, teleconnection patterns are hinting at a weakening of the NAO of which should aid in progression of the troughing to the north and a return to SW flow, resulting in a stretch of warmer than normal conditions.

AVIATION (06Z TAF Issuance)

Issued at 1231 AM EDT Sun May 3 2026

Impacts:

- VFR this Taf period

Discussion:

GOES19 shows clear skies across the TAF sites as strong surface high pressure was centered over southern IL and southern IN. This high will slowly move east today, but continue to maintain control of Indiana/s weather. Models suggest the arrival of mid level AC this afternoon associated with ongoing warm air advection aloft. This will result in the arrival of VFR cigs this afternoon which will persist through the Taf period. An isolated sprinkle or very light shower will be possible with these clouds, but confidence is not high enough for a mention at this point.

IND WATCHES/WARNINGS/ADVISORIES

Frost Advisory until 9 AM EDT this morning for INZ030-031- 037>042-046>049-054>057-062>065-070>072.