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KEY MESSAGES

- Scattered flurries or snow showers late this afternoon and tonight.

- Cold today and tonight. Wind Chill values around 0F today and -5 to -15 tonight.

SHORT TERM (Today and tonight)

Issued at 253 AM EST Sun Jan 18 2026

Surface analysis early this morning shows low pressure over Quebec along with a trough axis that extended across Ontario. High pressure was found over Texas, thus Indiana was caught between these two systems. Lower level flow this morning remained mainly cyclonic due to the influence of the low to the northeast. Ridging from the high was found across the plains. Aloft, a highly amplified pattern was in place, with strong ridging in place over the western CONUS and a largely cyclonic flow in place east of the Rockies due to a large trough stretching from the Great Lakes to eastern TX. The air mass over Central Indiana was an arctic one, with temperatures mainly in the teens and single digit dew points. GOES19 shows an area of clouds over IL and western Indiana advancing eastward across the state within the cyclonic flow. The clouds were producing only flurries or very light snow showers.

Today...

The surface and upper trough are expected to push across Central Indiana today. This will lead to morning cloudiness and as this wave passes. However, in the wake of the wave, weak ridging arrives for the late morning and early afternoon amid subsidence aloft. Forecast soundings at that time show a dry column with descending cold air through the afternoon. Things will change quickly late this afternoon as another quick moving upper trough within the cyclonic flow aloft passes across Central Indiana. Forecast soundings here indicates a top down saturation occurring through the mid to late afternoon hours. Within the lower levels dry air remains in place with very low dew points. Thus clouds are expected to return, and perhaps a flurry or snowflake will be seen, but it will not be very impactful.

What will be impactful today will be the temperatures and the associated winds. A very cold air mass will be in place across Central Indiana as 850mb temps will remain near -12C to -14C. This with translate to steady temperatures in the teens along with winds around 10-15 mph. These two elements will lead to wind chill values in the around zero. Although this will be well above advisory criteria, it will still feel like a very cold day.

Tonight...

The afternoon trough axis will be pushing across Central Indiana during the evening hours and exiting overnight. Cyclonic flow remains in place within the lower levels as another area of low pressure lingers in the Great Lakes providing a cold NW flow of air to central Indiana. More cold air advection will be expected tonight, as 850mb temps once again fall to near -18C, leading to another cold night with single digit lows. Digressing back to the passing trough, Forecast soundings again shows saturated mid and upper levels as this feature passes late this evening and early overnight. Lower levels remain quite dry, indicative of the very dry air in place at the surface. Thus as this wave passes, more very light snow showers or flurries will be expected, with minimal to no accumulations.

LONG TERM (Monday through Saturday)

Issued at 253 AM EST Sun Jan 18 2026

Monday Through Wednesday.

Much of the early portions of the long term period will be dominated by persistent cyclonic flow aloft and much below normal temperatures. There may be a few lingering flurries across north central Indiana Monday morning, but expect this to be brief with the better forcing closer to the Great Lakes. It will remain breezy through the day with strong pressure gradients with gusts to around 25-30 mph likely at times during the day. This will keep wind chills sub-zero through the day for areas along and north of I-70.

Surface flow will gradually become more southwesterly and weaker Monday night into Tuesday as the upper level system exits to the northeast. This will help to bring somewhat warmer temperatures Tuesday into Wednesday, but overall only expect a 6-8 hour window Wednesday afternoon where temperatures will climb above freezing. A clipper system will interact with the strengthening southerly flow during the daytime hours on Wednesday which could bring precipitation to portions of central Indiana but there remains quite a bit of model spread on the timing of the clipper and how much moisture is available across central Indiana by the time the better forcing arrives. With temperatures near freezing, precipitation type also remains uncertain with the potential for both rain and snow.

Thursday Through Saturday.

Another blast of colder air moves in Wednesday night into Thursday in the aftermath of the system but the magnitude of the colder air doesn't look quite as robust as what is expected for the early portions of the week. Surface flow will quickly then return to a more southerly direction Thursday night into Friday with another day where temperatures briefly climb back above freezing before the next system moves in to start the weekend.

The Saturday system has seen quite a bit of attention over the last week with some model runs showing extreme amounts of either freezing rain or snow. These more extreme runs have been the outliers with both the ensembles and latest deterministic runs showing the potential for accumulating snow across central Indiana, but nothing significant at this time. There remains quite a bit of spread in the strength of the system and with precipitation type so will continue to monitor forecast trends in the coming days.

AVIATION (06Z TAF Issuance)

Issued at 1153 PM EST Sat Jan 17 2026

Impacts:

- Some VFR early overnight before coming MVFR late overnight and on Sunday.

Discussion:

Cyclonic flow remains across central Indiana due to low pressure found well to the northeast. GOES16 shows some breaks in the cloud across the TAF sites, however an area MVFR cigs were found over IL, poised to push across Central Indiana. This will allow our current VFR cigs to become MVFR overnight.

The cyclonic flow will lessen after 12Z as the low to the northeast pulls away and ridging associated with high pressure over the southern plains builds across Indiana. Time heights continue to suggest lower level moisture present, thus will continue with some MVFR conditions through the morning, before heating allows the possibility of brief VFR Cigs in the afternoon.

Another low and associated cold front will push quickly toward Central Indiana by late Sunday. This will usher a return of lower level moisture and expected MVFR cigs as this trough passes on Sunday night. Moisture remains limited with this feature but a few light snowflakes or snow showers cannot be ruled out.

IND WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory from 4 AM to 11 AM EST Monday for INZ021- 028>031-035>049-051>055-060-061-067.