textproduct: Indianapolis

KEY MESSAGES

- Warm and dry conditions expected for Tuesday with highs in the low 70s

- Widespread rain arrives late Tuesday night and continues into Wednesday

- A return to more seasonable, cooler temperatures is expected late week through the weekend

DISCUSSION (This evening through Monday)

Issued at 242 PM EST Mon Nov 2 2026

Tonight.

The short term period will be characterized by anomalous warmth and increasing low level moisture ahead of an approaching central US trough. For tonight, the main forecast challenge relies on low level saturation and stratus trends. Model soundings and HREF probabilities indicate a persistent subsidence inversion aloft trapping boundary layer moisture. This will result in widespread stratus overnight. With weak forcing and lack of deep moisture, precipitation will be mostly limited to patchy drizzle and even this should end no later than midnight. Overnight lows will remain quite mild, generally in the middle 50s, due to the blanket of stratus and steady southerly surface flow.

Tuesday and Wednesday.

A deep upper level trough positioned over portions of the Great Plains and Rockies Monday will continue to amplify and eject towards the upper Midwest. In response, a tightening pressure gradient and subsequent height/pressure falls will aid in sustaining 35-40 kt of southerly flow at 850mb, transporting unseasonably warm, moist air from the Gulf across Indiana tomorrow. Strong WAA and vertical mixing supports near-record high temperatures in the mid to upper 70s. However, a trailing cold front approaching from the west may provide a small amount of synoptic ascent during the daytime for the development of a few mid-to-high level clouds that could hinder high temperatures by a few degrees, and prevent any records from being broken.

By Tuesday evening, the trailing cold front associated with the trough will be approaching areas to the west bringing with it a thin corridor of 60+ dew points along the leading edge. Strong isentropic ascent in the warm sector, PWAT values ~1.5 in slightly exceeding the 99th percentile for early November will support the development of widespread rain and thunderstorms in Illinois that will traverse into Indiana with time. Despite 50-60 kts of effective bulk shear, near-zero convective instability will preclude any widespread severe threat. However, a damaging wind gust or two cannot be ruled out due to 50-55 kt winds just above the surface.

In addition, the CAMs are indicating the potential of a dry air intrusion to occur as the cold front passes through our area. In turn, combined with very limited instability, convection, and consequently rain rates, should weaken as the cold front traverses across Indiana. As a result, rainfall totals could range anywhere from 0.3-0.6 in, with areas in southern Indiana having the best chance for higher rainfall amounts where less of the dry air may preclude totals. However, in the event where the dry air intrusion may be weaker or training of convective cells occurs, rainfall totals could be as high as 1.5 in. Any flash flood potential will be mitigated due to the onset of dry soil conditions over the last month.

Once the cold front traverses the region Tuesday night, Wednesday will bring light residual shower activity in the CAA region behind the cold front, and more seasonable air with highs reaching into the low 60s and lows reaching into the mid 40s.

Wednesday Night Through Monday.

Broad cyclonic flow and a cold core aloft may allow for lingering stratocumulus through Thursday, but sensible weather will remain dry. Highs will retreat into the low 60s on Thursday. Heading into Friday and the weekend, ensemble guidance paints a high confidence picture of a pattern shift toward more seasonable November weather. Surface high pressure will slowly build eastward out of the Plains while persistent northwest flow aloft dominates. Thermal profiles highlight 850mb temperatures falling near or slightly below 0C. This CAA regime will keep daytime highs suppressed in the 50s Friday through Monday, with overnight lows dipping into the 30s and 40s. A few weak shortwaves embedded within the northwest flow may pass through the Great Lakes over the weekend, but moisture return looks largely cut off by the Gulf of Mexico trajectory, keeping precipitation chances minimal. We will maintain a largely dry forecast through Monday with near normal temperatures.

AVIATION (18Z TAF Issuance)

Issued at 1148 AM EST Mon Nov 2 2026

Impacts:

- High IFR and low MVFR cigs to improve to VFR during the overnight hours - Lingering MVFR to IFR vsbys due to drizzle to improve to VFR after 20Z - Southerly wind gusts up to 25kt after 12Z Tuesday

Discussion:

Low level saturation persists across central Indiana leading to continued drizzle and low cigs. These conditions will improve this evening into the overnight hours as dew point depressions begin to increase as a response to drier air advecting in at the low levels. Conditions should improve to VFR around 00Z but there are some signs that low clouds may stick around into the early overnight with some question how extensive they will be. Marginal LLWS conditions are likely towards daybreak as the LLJ ramps up ahead of the Tuesday night system, but should remain brief enough to not warrant a mention in the TAF. Southeasterly winds will become more southerly late tonight with gusts up to 25kt after 12Z tomorrow.

IND WATCHES/WARNINGS/ADVISORIES

None.