textproduct: Indianapolis

KEY MESSAGES

- A few showers are possible late this afternoon.

- The next best chance for rain will be Sunday into Monday

- Below normal temperatures will continue for much of the period

DISCUSSION (This evening through Thursday)

Issued at 216 PM EDT Thu Jun 18 2026

Surface analysis early this afternoon shows low pressure over eastern Ontario, providing cyclonic flow across Indiana. High pressure was found across the NW plains states. A frontal boundary was found still lingering across KY. A secondary cold front was pushing south across Indiana. GOES19 shows convection over KY, associated with the frontal boundary. Otherwise, some high clouds were pushing across IL into IN within the WNW flow aloft. A few showers were found with this. Water vapor overall shows mainly a zonal flow in place across the CONUS, with subsidence in place across the plains into Indiana. Large Surface high pressure was found over the northwestern plains, building east.

Tonight...

Clouds associated with the passing weak upper wave will quickly exit the area overnight as high pressure continues to build across Indiana. This will lead to mostly clear skies. Cold air advection and falling dew points should allow for lows in the middle 50s.

Friday through Saturday...

The large surface high pressure system over the plains will drift toward and across Indiana on Friday through Saturday, providing fair and mild weather. Time heights show broad subsidence remaining in play through this period as little in the way of upper forcing passing in the W-NW flow aloft. That flow was due to the weak ridging building across the western CONUS. Otherwise, forecast soundings show a dry column on Friday that should lead to partly cloudy skies at that time.

Forecast soundings on Saturday show some mid level saturation, but dry lower levels as some slight warm air advection comes in to play. We will expect a few more clouds on Saturday as compared to Friday, but there will still be some sun. Expect below normal temperatures with highs near 80.

Sunday and Monday...

Sunday and Monday will be the next best chance for showers and thunderstorms across Central Indiana. Within the mainly zonal flow aloft, a moderate short wave will pass across Indiana. An associated warm front will approach central Indiana early Sunday morning, followed by an area of surface low pressure and associated cold front passing across Indiana on Monday. Ample moisture appears in place as this forcing passes. Thus continued chances for showers and thunderstorms will be needed.

Tuesday through Thursday...

Mainly dry weather will be expected through this period. The mainly zonal flow will remain in place aloft and little in the way of forcing dynamics are suggested to pass until Thursday. Surface high pressure will be lingering across the area on Tuesday through Thursday, with mainly westerly flow in place. Thus only some low pops will be included for now on Thursday as the subtle forcing aloft is suggested at the moment. The mainly zonal flow aloft with will keep hot and humid air at bay, resulting in slight below normal temperatures.

AVIATION (00Z TAF Issuance)

Issued at 725 PM EDT Thu Jun 18 2026

Impacts:

- WNW winds gusts near 20 kts Friday afternoon.

Discussion:

VFR conditions are expected through the period.

Scattered to broken VFR deck between 040-060 will decrease this evening. Winds will be light out of the W-NW overnight thanks to weak pressure gradient and nocturnal effects.

Tomorrow will start out with mostly clear skies, gradually turning into a BKN deck of clouds by afternoon as daytime heating develops and sufficient moisture in the lower altitudes remain. Cloud ceilings are expected to be similar to today, around 050. As deeper mixing develops (aiding in the cloud development) WNW winds will increase with some gusts between 18-20 kts developing by early afternoon.

IND WATCHES/WARNINGS/ADVISORIES

None.