textproduct: Indianapolis

KEY MESSAGES

- Pockets of drizzle,fog and light rain through the first half of today

- Warm through the weekend with near record highs Sunday

- Rain with a few thunderstorms Sunday afternoon and evening, possibly ending as a brief period of light snow early Monday

- Much colder next week

SHORT TERM (This evening through Saturday)

Issued at 224 PM EST Fri Dec 26 2025

Rest of Today and Tonight.

Main focus for the short term period will be tracking the potential return of fog tonight in the aftermath of this afternoon's frontal passage. Synoptically an upper level low is exiting the Great Lakes with a surface cold front stretching to the southwest. As of early this afternoon it had mostly passed through central Indiana with surface flow now generally now westerly to northwesterly. Occasional gusts of 20-25 mph will continue over the next few hours before the stronger pressure gradients associated with the exiting system begin to relax. Breaks in the clouds have been few and far between with expectations that these conditions will continue through the overnight with a strong inversion above the cloud layer.

Heading into tonight, cloud bases will begin to fall again with the potential for fog across central Indiana. Models aren't too bullish on the potential compared to previous nights, but as winds drop to near calm in the aftermath of the frontal passage, there will be plenty of residual near surface moisture which should allow for at least patchy fog with areas of fog likely. Confidence in coverage of dense fog isn't quite as high with the uncertainty in the drop in dew point depressions, but trends will need to be monitored through the evening.

Saturday.

Another pattern shift is expected going into Saturday as the surface flow once again becomes more southeasterly ahead of a stronger upper level system that will impact central Indiana during the late weekend into early next week. The persistent low clouds will stick around through much of the day again tomorrow with little signs of breaking even moving into the long term period. When it comes to temperatures, there is a larger than normal model spread for 24 hours out with the uncertainty as to how much the southeasterly flow will be able to help bring warmer air into the area. Currently thinking temperatures will be on the lower end of model guidance with the expected cloud cover, but there could be at some locations that reach into the mid to upper 50s in the far south.

LONG TERM (Saturday night through Friday)

Issued at 224 PM EST Fri Dec 26 2025

Saturday Night... Broad upper level ridging remain the dominant feature across the Eastern CONUS, with high pressure sliding through the Great Lakes. Despite the ridging positioned to the north, the stratus layer is likely to remain parked across the Ohio Valley with the low-level flow holding tight across the region Sat ngt into Sun. This is common to see stratus deck locked in when you have a stubborn subsidence inversion and keeps low-level moisture trapped. But the low-level warm air advection advecting north should slowly lift or erode some clouds. Not entirely though, but some pockets of blue sky could occur. Temps will still be in the mid 50s to perhaps low 60s.

Sunday through Sunday Night... the main feature change here has been the delay of the frontal passage. Synoptic evolution by a deep, positively tilted 500mb trough digging into the Central Plains. A positive tilt often delays the eastward progression of a surface cold front as the primary forcing remains displaced to the west.

Consensus amongst ensemble members continues to increase with minimal spread, indicating that the frontal passage likely will not occur until late Sunday or perhaps early Mon morning. This keeps the region in an unseasonably warm, moist air mass through the duration of Sunday. Moisture instability will be present, as a stout 50-60kt llvl jet will advect a plume of moisture with PWAT values nearing 1.25 inches, which is abnormal for this time of year. There does appear to be a convective risk for late Sun, as dewpoints climb to near the upper 50s to perhaps even 60 in some spots. Despite guidance hinting at low MLCAPE values, the presence of strong low- level shear all suggests that some low-topped convection could efficiently transport higher energy to the surface and result in some thunderstorm activity. Highs Sun could also touch record values, cloud cover will be the main item to monitor. Any breaks in clouds and temps could easily push to near 70 degrees.

Monday will be a return to winter, in an abrupt way. 850mb thermal trough makes a quick return and will cause temps to crash quickly, which could introduce a concern for rapid freezing; however, most guidance indicates that frontal passage will also have a narrow dry slug quickly approach and this should be enough to cause subsidence at the surface drying the environment out quickly before any freezing issues develop. The arctic airmass pushes the cold air back into the Ohio Valley by Tuesday, with the high pressure dominating the atmosphere through much of the upcoming week. This will keep a more continental polar airmass for Indiana, as temps generally will be in the 20s and overnight lows in the single digits to teens. Perhaps some flurries a few days, but at the current setup suggests there isn't any large scale system progged to impact Indiana next week, other than a couple weak clipper systems.

AVIATION (18Z TAF Issuance)

Issued at 1134 AM EST Fri Dec 26 2025

Impacts:

-Low MVFR to IFR cigs through the evening, IFR to LIFR tonight -MVFR vsbys with BR through the evening, potentially IFR to LIFR tonight -A few southerly wind gusts to 25kts through the afternoon

Discussion:

Cigs will bounce from low MVFR to high IFR through the afternoon with persistent 5-8 mile vsbys. Cigs are then expected to consistently drop to IFR after 00Z with periods of LIFR possible. Vsbys may also drop as low as LIFR to VLIFR due to fog, but confidence is not quite as high as in previous nights. Any lowered vsbys will begin to improve after 13Z tomorrow. Southerly to southwesterly winds will occasionally gust as high as 20-25 kits this afternoon before dropping to near calm during the overnight.

IND WATCHES/WARNINGS/ADVISORIES

None.