textproduct: Indianapolis

KEY MESSAGES

- Pleasant early summer weather continues through Friday

- Next chance for widespread rain will be late Saturday-Sat night

- Very warm and humid next week with occasional showers/t-storms

FORECAST UPDATE

Issued at 914 PM EDT Thu Jun 4 2026

Another pleasant evening ongoing as the region remains under the influence of high pressure. While diurnal cu has diminished...there has been an increase in mid and high level clouds as moisture aloft advects into the region to the northwest of the high pressure center. 01Z temperatures were in the 70s.

Forecast is in excellent shape overnight. Dry weather continues with alight southerly wind through daybreak. The ridge axis aloft will shift east tonight which will enable continued upper level moisture to spread into the region. Nudged up cloud cover to account for the expected increase in cirrus. Lows will fall into the lower and mid 60s.

Zone and grid updates out.

DISCUSSION (This evening through Thursday)

Issued at 234 PM EDT Thu Jun 4 2026

Today and tomorrow...

Very pleasant weather for early June continues across Central Indiana as high pressure remains the dominant weather influence. Variable winds earlier today already switched to southerly, advecting in a more moist, tropical-like airmass from the Gulf. Low level mixing up to 2 km agl this afternoon, present on current IND acars soundings, will slow the rise in humidity levels until Saturday when dew points are forecast to approach 70 degrees! 500mb vorticity and height maps today indicate upper ridging overhead with embedded convection in SW Arkansas associated with an upper wave. Guidance shows this wave weakening as it pushes northward into the area, but still increasing upper level moisture by tomorrow. Any storm threat is expected to hold off until at least Saturday locally.

With a warmer airmass on the way, expect a noticeable increase in surface temperatures today and tomorrow as highs reach the mid to potentially upper 80s. This patterns shift marks the beginning of an extended stretch of typical summer time conditions with warm to hot temperatures and frequent storm chances.

Saturday...

Transition into more typical mid-summer pattern is expected this weekend as the blocking ridge breaks time and transitions to a more progressive pattern aloft. Northern stream troughing pushes east into the Great Lakes this weekend, flattening the top of the ridge while a low level boundary becomes stretched W-E across the I-70 corridor. Lower confidence in timing and location of better- organized precipitation and mesoscale systems this far out as small discrepancies in details upstream can have significant affects on the downstream evolution of mesoscale features. For Saturday, will be watching how convection evolves Friday evening towards the Quad Cities region; however dry air locally may significantly weaken anything approaching Indiana during the early morning hours. Despite this, significant moisture advection ahead of the boundary on saturday should lead to an environment supportive of shower and storm development by late morning and into the afternoon hours. With the boundary likely within Central Indiana, convective initiation may occur overhead sometime on saturday depending on how quick the atmosphere can recover from potential early morning clouds and rain. While confidence is lower on the overall evolution of mesoscale features, the environment Saturday afternoon and evening along and ahead of the front should be supportive of a marginal severe threat due to increasing instability and humidity and 30-40 kts of deep layer shear. Any waves of energy along the front will be enough to spark off convection in this type of pattern.

Sunday through Next Week...

The 500mb subtropical ridge will re-establish itself through early next week over the Great Lakes and much of eastern Canada, with a corresponding amplified surface ridge from Quebec to the Deep South ...directing a copious supply of Gulf moisture into the region by the end of the weekend. At times scattered showers and isolated, embedded pulse storms capable of stronger winds and downpours will certainly be on the table...with perhaps localized flooding the greatest concern given the stalled nature of the boundary.

Upper ridge axis should slide a bit east of Indiana around the Tuesday timeframe, but at least widely scattered diurnally-driven showers should be the rule through the end of the forecast period. Otherwise between any convective showers, very warm and humid, July- like weather can be expected amid lighter, mainly southerly breezes that will maintain dewpoints in the upper 60s to around 70 through at least Wednesday.

AVIATION (06Z TAF Issuance)

Issued at 1232 AM EDT Fri Jun 5 2026

Impacts:

- Wind gusts peaking at 20 to 25kts this afternoon - Scattered showers and storms possible near KLAF this evening

Discussion:

Predominantly VFR conditions are expected through the forecast period.

High pressure will remain the primary feature impacting the Ohio Valley for much of today as it shifts into the southeast States. This will enable the frontal boundary focused from the upper Midwest through the central and southern Plains to move closer to the region by this evening. Deeper moisture advection will commence as Gulf moisture is drawn north on the back side of the high. This will result in greater diurnal cu coverage for this afternoon along with a steady increase in mid and high clouds. Potential is there for scattered convection to impact KLAF by this evening but primary impacts from rain and storms should hold off at the terminals until late tonight into Saturday.

Southwest winds will gust up to 20 to 25kts at times this afternoon then diminish to light southerly tonight.

IND WATCHES/WARNINGS/ADVISORIES

None.