textproduct: Indianapolis

KEY MESSAGES

- Mainly sunny with mild temperatures this afternoon

- Rain expected Monday night through Tuesday night

- Turning colder beginning Wednesday into next weekend

- Watching next weekend into the following week for a strong storm system to bring rain, snow, and large temperature swings to Indiana

FORECAST UPDATE

Issued at 948 AM EST Sun Nov 23 2025

Fog and stratus continued over a good part of central Indiana this morning, as low level moisture was advected into the area. Visibilities are starting to improve, but the stratus continues to spread.

Stratus should still mix out later this morning or early this afternoon with mixing and general subsidence, allowing sunshine to return to those areas. Nudged down high temperatures in areas with clouds, but will wait and see how fast the dissipation actually occurs before making more changes to temperatures.

SHORT TERM (Today and Tonight)

Issued at 248 AM EST Sun Nov 23 2025

A weak frontal boundary is working through the forecast area early this morning. An area of mid level clouds out ahead of the boundary was already moving away to the southeast leaving skies mostly clear over much of central Indiana. 06Z temperatures were largely in the low and mid 40s.

Quiet conditions will continue through the short term as high pressure reestablishes across the Ohio Valley in the wake of the frontal passage this morning. The high will remain the predominant weather feature through early Monday as it shifts off to the east with dry weather and mild temperatures with upper level ridging expanding into the region.

There remains a chance for scattered low stratus development over the next few hours through daybreak along the front as it presses southeast. To this point the stratus has held well to the north of the region over southern lower Michigan. That being said...an axis of higher RH progs in the 950-925mb layer does at least offer the possibility for some development of stratus into the region. The overall dryness of the airmass will be a limiting factor.

Any stratus that can form should be gone by mid morning with mainly sunny skies expected for the duration of the day. Thin cirrus will drift across the region within the northwest flow aloft east of the approaching upper level ridge but even this should be pushed to the east of the forecast area by this evening as the center of the high moves across the region. High level clouds will return predawn Monday in advance of a developing storm system ejecting out of the central Rockies. In spite of that...near calm winds and the developing of a shallow yet sharp inversion does support potential for some fog to develop prior to daybreak Monday.

Temps...low level thermals support highs in the low and mid 50s this afternoon. Lows tonight will drop into the low to mid 30s under decent radiational cooling conditions.

LONG TERM (Monday through Saturday)

Issued at 248 AM EST Sun Nov 23 2025

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

Monday and Tuesday...

Monday starts off mild and relatively quiet compared to the rest of the week as the region will be under ridging aloft within a warmer, southwesterly flow pattern ahead of an incoming trough to the west. A strengthening low level jet and southerly flow through the column will be advecting moisture northward into the region resulting in increasing cloud cover. Despite a lack of sunshine, warm air advection and well above average low and mid level temperature anomalies support high temperatures reaching the low to mid 50s.

Weak troughing lifts northeastward into the Great Lakes Monday night while a jet streak overhead and an increasing low and mid level jet provide enough lift and moisture for widespread rain. Precipitation develops southwest of the region during the day Monday then pushes in from the west Monday evening and into the overnight hours. Not expecting thunderstorms with this system as instability is fairly limited to non existent, however steeper mid/upper level lapse rates and enhanced lift under the exit region of the jet may lead to heavier rainfall rates at times. A quarter to three quarters of an inch of rain is currently expected across Central Indiana, with the higher amounts within the southeastern half.

The bulk of the rainfall moves eastward Tuesday morning with a drying trend expected during the day. 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, Tuesday will feature above normal temperatures once again. Cloudy skies persist but southwest winds and steepening low level lapse rates support highs in the mid to maybe upper 50s.

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 strong front pushes through the state early Wednesday morning, with scattered showers and snow showers likely along it. 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 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.

For now, the weekend looks to start out as a period of light snow Saturday before a transition to rain as a strong frontal boundary sets up to the west with waves riding along it. Latest trends have Indiana on the warmer side of the front going into Sunday with higher rainfall chances... but confidence remains low as this is still a week away and guidance will likely struggle with this complex set up. This 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 (18Z TAF Issuance)

Issued at 1200 PM EST Sun Nov 23 2025

Impacts:

- IFR conditions in stratus and fog expected most sites tonight into Monday morning

Discussion:

Mixing and subsidence continue to dissipate the stratus and fog this morning. VFR conditions are expected into the evening hours.

Later this evening and into the overnight, stratus and fog will redevelop and move north as low level moisture returns. This will likely create IFR conditions, with lower conditions possible. Questions remain on whether stratus or fog will be dominant and exactly how low conditions will get.

For now will go with IFR visibility and near IFR ceilings, and later issuances can refine. These conditions will improve by late Monday morning.

IND WATCHES/WARNINGS/ADVISORIES

None.