textproduct: Indianapolis

KEY MESSAGES

- Rain will expand across the area from the southwest today

- Additional rainfall early next week with much cooler weather likely post-Thanksgiving

FORECAST UPDATE

Issued at 951 AM EST Fri Nov 21 2025

Visibilities continue to slowly improve across central Indiana, with dense fog becoming more isolated. Rain slowly moving in will also help improve visibility from very low values. Given this, will let the Dense Fog Advisory expire at the top of the hour (15Z).

Rain will continue to slowly move north and east today as isentropic lift also shifts north. Adjusted PoPs based on latest trends seen on radar, but overall the ongoing forecast looks good.

Low clouds will help keep temperatures from rising too much. Left highs alone for now and will monitor.

SHORT TERM (Today and Tonight)

Issued at 301 AM EST Fri Nov 21 2025

Dense fog with visibilities of 1/4-1/2SM has become prevalent across the northern half of the forecast area early this morning as moisture remains trapped within the near surface layer under a shallow inversion. 07Z temperatures had moved little from readings on Thursday in the mid and upper 40s.

The fog and low ceilings will persist as the primary concern for the next several hours past daybreak but the approach of low pressure currently over the central Plains will spread rain across much of the area through tonight.

Have expanded the Dense Fog Advisory to cover the northern half of the forecast area through 15Z based on obs and webcams. With near calm surface winds and model soundings showing no weakening of the shallow inversion...there is nothing available to offer a mixing component to the near surface layer through daybreak and potentially for a good chunk of the morning. The arrival of the broad area of rain to our southwest currently across the Ozarks east into the lower Ohio Valley will eventually serve as a catalyst to dissipating the dense fog but that will take some time as gradually stronger isentropic lift expands into the region and slowly erodes the dry layer present in the 850-500mb layer. Rain will move into the lower Wabash Valley over the next few hours with a slow expansion to the northeast through the morning as that deeper isentropic lift sets up. Heaviest rainfall will align across southern portions of the forecast area immediately north of the warm front by this afternoon with lighter amounts north of Interstate 70.

Rainfall rates will drop back this evening as deeper moisture shifts east with a developing wave along the boundary that will become the primary surface low as it transitions into the mid Atlantic region by Saturday morning. Model soundings though maintain saturated conditions below 700mb which combined with the trailing upper level wave axis set to pass through prior to daybreak Saturday will support light showers lingering through much of tonight. Light rain will end prior to daybreak Saturday from northwest to southeast as drier air and broad subsidence advects into the region in wake of the upper wave. This will ultimately lead to clearing skies from the northwest beginning predawn through daybreak Saturday and the return of sunshine for much of the upcoming weekend.

Temps...the model blend continues to be much too optimistic on warming for today which will be stunted substantially by the low clouds and rain. Nudged 3-4 degrees cooler for highs ranging form the upper 40s to mid 50s. The clearing towards daybreak Saturday will enable lows to drop into the mid and upper 30s over the northern half of the forecast area with 40s further south.

LONG TERM (Saturday through Thursday)

Issued at 301 AM EST Fri Nov 21 2025

Seasonably mild and dry weather is expected over the weekend as the recent quasistationary front is finally moved out of the region by the system expected to bring rain to the area today.

The next rainmaker for the area is the closed low currently over the West Coast, which will gradually shift northeastward and may phase with a northern stream upper level disturbance as both promote lee cyclogenesis over the central Plains, with the resultant surface low moving quickly into the Great Lakes early to mid next week. This system will bring another round of rain to the area as late Monday, with the most significant rain chances Monday night into early Tuesday.

Depending upon the intensity of the upper low/trough, there will be some low potential for lingering rain as late as Tuesday night into Wednesday, but these chances are far more uncertain at this point.

What is more certain is that a fairly substantial cooldown is likely for Thanksgiving and beyond, though the exact magnitude of the colder conditions remains to be seen. At the moment, highs in the 30s and lows in the 20s and perhaps upper teens appear likely.

AVIATION (12Z TAF Issuance)

Issued at 538 AM EST Fri Nov 21 2025

Impacts:

- Widespread IFR/LIFR conditions through tonight - Rain overspreading the terminals through the morning

Discussion:

Very poor flying conditions will continue for most of the forecast period as moisture remain trapped in the near surface layer beneath an inversion. Ceilings hovering early this morning at or below 1000ft and expect that to continue. Ongoing dense fog impacting KIND especially will improve by 14-15Z to MVFR visibilities. Patchy drizzle is possible early then rain will expand into the region first reaching KHUF and KBMG in the next couple hours then the other terminals by midday/early afternoon.

Widespread rain is expected to last into tonight with the potential for the heaviest rainfall at KBMG. IFR and lower ceilings will persist into tonight. Rain will end during the predawn hours Saturday with clearing of the low ceilings reaching KLAF near daybreak Saturday and the other terminals later on Saturday morning. Near calm winds early this morning will shift to east- northeast at 5-7kts this afternoon then northeast tonight.

IND WATCHES/WARNINGS/ADVISORIES

Dense Fog Advisory until 10 AM EST this morning for INZ021- 028>031-035>049-051>057.