textproduct: Indianapolis

KEY MESSAGES

- Areas of fog this morning with dense fog focused across the southwest half of central Indiana

- Rain expected tonight through Tuesday night

- Turning colder beginning Wednesday into next weekend

- Watching Saturday into the following week for strong storm systems to bring rain, snow, and large temperature swings to Indiana

SHORT TERM (Today and Tonight)

Issued at 257 AM EST Mon Nov 24 2025

A shallow stratus deck with dense fog continues a slow northward expansion across south central and southwest Indiana while skies were mainly clear elsewhere with pockets of fog. 07Z temperatures ranged from the upper 20s over the north to near 40 in the lower Wabash Valley.

High pressure remains over the area early this morning but will move off the Mid Atlantic coast by this evening as developing low pressure ejects out of the Rockies and kicks east into the southern Plains. The low will pivot northeast into the Ohio Valley by Tuesday morning with rain becoming widespread tonight.

The first issue for the short term focuses on the fog and stratus ongoing across the southwest part of the forecast area. The northward expansion has been slow to this point but RH progs in the 975-950mb layer suggest deeper moisture gradually encompassing the southwest half of the forecast area after daybreak underneath a shallow but very strong inversion. With this in mind...expect lower ceilings and areas of fog to lift north slowly as well over the next few hours. At this point...the Dense Fog Advisory covers the situation nicely with no plans to expand with the morning forecast package. Would prefer instead to monitor trends through the predawn hours and add counties as needed based on observations and webcams. Visibilities should improve through mid morning as winds increase within the near surface layer and the inversion weakens.

Thin high level clouds are already moving into the forecast area from the west early this morning and will continue to overspread and thicken through midday. The weakening of the inversion and increasing mixing through the boundary layer should lead to a gradual decrease of the low stratus deck over the lower Wabash Valley but it may take the first half of the day to largely diminish. Continued influx of moisture aloft into the region will lead to a gradual thickening and lowering of clouds through late day with minimal sunshine largely confined to the morning across the northeast half of the forecast area.

The arrival of broader isentropic lift this evening in advance of a strengthening low level jet will lead to top down saturation and the onset of rain from southwest to northeast through the evening. Rain will become widespread overnight as the low level jet noses into the Ohio Valley with the potential for up to a half inch of rain along and south of I-70 by daybreak Tuesday. Lighter amounts are expected over northern portions of the forecast area further away from the stronger low level jet.

Temps...temperatures remain a bit tricky for today and are dependent on how quickly the low clouds erode. Nudged highs down over the lower Wabash Valley especially into the lower 50s with mid 50s expected elsewhere. Lows tonight will drop little with the clouds and rain as most locations hold in the upper 40s.

LONG TERM (Tuesday through Sunday)

Issued at 257 AM EST Mon Nov 24 2025

An active weather pattern continues next week with numerous systems bringing large temperature swings, rain, and windy conditions to the state.

Tuesday...

Weak troughing lifts northeastward into the Great Lakes Monday night while a jet streak overhead and an increasing low and mid level jet bring moisture northward into the state. The best moisture convergence is currently expected to remain south of central Indiana, however, modest isentropic lift within the strengthening LLJ support widespread rainfall early Tuesday morning with lingering showers through the day. Mid-level moisture will be minimal throughout, but strong upper level support and saturation above 500mb could lead to high rain rates at times. Generally, QPF totals for this event are likely to remain below 1 inch with most areas below 0.5 inches, highest rainfall amounts likely south of I-70.

Southwesterly flow persists behind this initial system as a much stronger trough and associated low develop over the Northern Plains and Upper Great Lakes. With the cold air locked up north behind the next system and a warmer airmass still overhead, high temperatures in the mid 50s to low 60s are expected despite clouds and showers.

Wednesday through Friday...

A significant pattern shift arrives the day before Thanksgiving as a strong trough to the north and associated front usher in an arctic airmass over the entire region. The front pushes through the state early Wednesday morning, but the lack of moisture behind the pressure trough passage earlier on Tuesday will limit rain shower coverage along the boundary. Despite only isolated to scattered showers signifying the front, the temperatures disparity along this frontal axis will be large, with temperatures quickly falling 10-15 degrees within a few hours from the low 50s to upper 30s early Wednesday morning.

Steepening low level lapse rates as much colder air advects in aloft along with a strong 30-40 kt low level jet will make for a cold and windy day. West northwesterly winds 15-25 mph with gusts over 35-40 mph are likely...stronger gusts may be possible. Lower confidence in the temperature forecast for Wednesday as guidance may not be handling the set up well as temperatures may not follow a typical diurnal pattern. High temperatures may be reached early in the day before the front, with steady or falling temperatures in the 30s during the afternoon and evening. Wind chill values will likely remain below freezing all day, dropping into the teens by Wednesday night. Not too concerned with wintry weather at the moment as enough dry air should be advecting in, limiting snow showers within the cyclonic northwest flow pattern; however would not be surprised to see on and off flurries.

Winter-like temperatures and breezy conditions persist Thanksgiving and Friday as strong northwesterly flow keeps an arctic airmass entrenched over the region. While conditions will be fairly dry, high temperatures may struggle to get above the freezing mark while wind chill values stay in the teens and 20s.

Next Weekend into Early December...

Confidence is increasing in a significant storm system and strong baroclinic zone developing next weekend and into the first week of December, setting the stage for an active period with widespread precipitation and large temperature swings. Long range guidance has been consistent in showing an active southwesterly subtropical jet across the Central and Southern CONUS in response to a sharpening SW to NE temperature gradient setting up from the Plains to the Great Lakes. This classic winter-time pattern can bring widespread heavy rain, snow, and storms to a large portion of the CONUS. While confidence is low on the specifics and exact evolution of mesoscale and synoptic scale features, confidence is increasing in this pattern developing with Central Indiana within or near the main storm track.

The set up for Saturday is fairly complex as longer range guidance indicates a weak trough approaching from the northwest within the northern branch of the jet, while the subtropical jet increases southwesterly flow aloft through the Ohio Valley. Interactions from both the northern and southern branches of the jet can result in favorable set up for snow. Flow becomes southerly going into Saturday as a surface low tracks across the Midwest into the Great Lakes with sufficient moisture advection northward with a 30 kt LLJ overhead. Deeper cold air in place from the previous few days may take a while to retreat northward, setting the stage for a quasi overrunning event where warmer moist air overruns a cold, denser airmass at the surface. While confidence is lower in the finer details of this set up and the overall evolution and track of synoptic features, this will be a system to watch as any snow this time of year can cause major travel impacts. Keeping snow in for the first half of the day Saturday, transitioning to a rain/snow mix during the afternoon, then all rain by the evening. This is an initial forecast and details will likely change and be fine tuned over the next several days.

The active pattern is expected to persist into the following week with additional waves of precipitation tracking through the state and large temperature swings. We will be monitoring this timeframe closely and updating the forecast accordingly as confidence increases on timing, track, and impacts.

AVIATION (12Z TAF Issuance)

Issued at 540 AM EST Mon Nov 24 2025

Impacts:

- LIFR/VLIFR conditions in stratus and fog at KHUF through most of the morning and potentially at KBMG as well - Rain developing this evening with deteriorating conditions to IFR and lower tonight

Discussion:

Dense fog and very low stratus at or below 500ft continue to impact KHUF early this morning and will continue to do so over the next 3 to 5 hours with only slow improvement into the early afternoon. The stratus and fog has been just to the south and west of KBMG over the last couple hours and it remains likely that restrictions will develop for part of the morning here as well. Ongoing patchy fog at KLAF will improve shortly after sunrise.

Ceilings will slowly thicken and lower through the course of the day as progressively deeper moisture in the mid and upper levels advects into the region from the west. Ceilings will once again lower this evening and eventually drop to IFR or lower overnight as rain becomes widespread over central Indiana.

Near calm winds early this morning will become S/SE at near 10kts this afternoon then weaken slightly tonight.

IND WATCHES/WARNINGS/ADVISORIES

Dense Fog Advisory until 11 AM EST this morning for INZ051>053- 060>064-067>072.