textproduct: Indianapolis

KEY MESSAGES

- Gusty winds between 30-40mph today and Wednesday.

- Scattered rain showers tonight, changing to snow showers on Wednesday

- Minor snowfall accumulations from a dusting to around 1 inch possible.

- Well-below normal temperatures later this week into early next week

FORECAST UPDATE

Issued at 917 AM EST Tue Jan 13 2026

Surface analysis late this morning shows low pressure in place over northern Ontario. High pressure was in place across the deep south. This was resulting in a moderate pressure gradient across Indiana which was caught between these two systems. Aloft, ridging was found over the western CONUS. This was allowing ridge riding Pacific moisture to stream across the northern Rockies into the Central Plains. Abundant mid cloud was shown on GOES19 streaming across IL and entering Indiana, associated with this Pacific moisture. Water vapor imagery shows an upper low over WI. This feature was producing some precipitation over WI and MI. Lurking across Ontario was a cold front, sagging southward with Arctic air in its wake.

Warm air advection remains in play this afternoon on westerly flow aloft. The upstream clouds are failing to produce any precipitation or lower level clouds as the lower levels are not set up well for any precipitation. Given the flow aloft the mid and high cloud will continue to stream across Indiana leading to mostly cloudy skies. Forecast soundings show upper level saturation with dry lower levels this afternoon, which is on board with the arrival of these high clouds. Thus increasing cloudiness is expected. Given our warm air advection and good mixing due to the moderate pressure gradient, highs should be able to reach the lower 50s.

SHORT TERM (Today and tonight)

Issued at 306 AM EST Tue Jan 13 2026

Strong ridge-building over the eastern Pacific will allow a trough to dig southward over the Midwest later today and tomorrow. Cyclogenesis associated with this trough is taking shape well to our north over central Canada. The resulting low then progresses eastward along a path north of the Great Lakes. Though far to our north, the system will drive a cold front southward with cold air advection reinforced by the digging trough.

First, however, a period of strong warm air advection is anticipated as the MSLP gradient tightens ahead of the low. Gusty southwest winds between 30-40 mph will help pump temperatures into the 40s and low 50s today. Additionally, modest frontogenesis along the approaching front allows rain showers to develop after sunset. These rain showers should be light, and confined mainly across the southern half of our CWA.

Once the aforementioned cold front arrives early Wednesday morning, temperatures begin to fall quickly despite it being daytime. In fact, high temperatures on Wednesday should occur before sunrise, with temps falling into the 20s during the afternoon. Any lingering rain showers should begin to change to snow Wednesday morning as well. Guidance shows low-level instability within the post-frontal environment, which should promote a scattered/cellular characteristic to the snow showers.

Winds look to be out of the north, which will help maximize the fetch off Lake Michigan. A more coherent snow shower or snow band may develop which could extend southward enough to bring accumulating snow to parts of central Indiana. The best chance of this would be from Lafayette to the north suburbs of the Indy metro and points northeast. As much as an inch of snow is possible within this band. Elsewhere, a dusting is the most probable scenario.

LONG TERM (Wednesday through Monday)

Issued at 306 AM EST Tue Jan 13 2026

A pattern shift is expected in the long range with a trend towards colder than average temperatures. As mentioned in the short term discussion, strong ridge-building is occurring over the eastern Pacific. Ensemble guidance show this ridge becoming a dominant feature while evolving into a classic Rex Block. Ridging over the West Coast then reinforces troughing over the Midwest and Eastern US. The developing blocking pattern then locks it in for at least a week.

Global teleconnections support the developing pattern, with a positive Pacific North American Pattern (PNA) and an Arctic Oscillation (AO) quickly trending negative. A negative AO favors a highly amplified jet stream while the positive phase PNA favors ridging over the western US and troughing over the east. The combination of the two will help prolong deep troughing over the Midwest and eastern US. Troughing in turn promotes colder than average temperatures.

Scaling down a bit, guidance is in good agreement showing a series of vort maxes diving southeast within the broad northwesterly flow on the eastern flank of the Pacific ridge. Each likely has an attendant cold front with a reinforcing shot of cold air. Though potent, these systems lack moisture. Given the cold air mass likely to be in place, snow is favored over rain this weekend onward. Guidance differs regarding the timing and stretch of each wave, so we'll keep PoPs broad and prolonged through the weekend.

Temperatures through the period, as alluded to above, look to be well-below normal...except Friday, where a shortwave ridge is modeled to pass through with a brief period of modest warm air advection. Guidance is in good agreement showing sub-freezing highs from Saturday to the end of the period. Sunday looks to be the coldest day, with highs in the teens/low 20s and lows in the single digits. Wind chills likely dip below zero for a good chunk of the weekend into early next week.

Days 8-14...ensemble guidance is hinting at another pattern shift late next week where ridging shifts eastward and flattens somewhat. Such a pattern may allow for a trend towards warmer (but still below normal) temperatures and greater precipitation chances. An east-west oriented baroclinic zone may develop which will help determine the eventual storm track. Ensemble guidance tends to keep the AO strongly negative while allowing the PNA to trend negative as well, which adds weight to the potential pattern described above. However, ensemble guidance diverges considerably adding to forecast uncertainty. That said, take individual models runs / deterministic guidance with a grain of salt.

AVIATION (18Z TAF Issuance)

Issued at 1148 AM EST Tue Jan 13 2026

Impacts:

- Winds gusts near 30 knts this afternoon. - VFR conditions becoming MVFR late tonight. - Precipitation possible after 10Z.

Discussion:

A moderate pressure gradient across the area today along with warm air advection and good mixing will continue to result in gusty winds during daytime hours. GOES19 shows a stream of Pacific upper level moisture streaming across Indiana. Lower levels remain dry, thus no precipitation is expected.

Tonight, a cold front will push across Indiana from the north. Weak forcing with the front may allow for some light precipitation overnight and into Wednesday morning. Precipitation may begin as liquid, but by after 10-12Z...enough cold air will have arrived to create snow as the precip type. Time heights and forecast soundings suggest lower level saturation and MVFR cigs in the wake of the cold front as an upper trough and associated dynamics continue to push across Indiana.

IND WATCHES/WARNINGS/ADVISORIES

None.