textproduct: Indianapolis

KEY MESSAGES

- Winter Storm Warning through midnight tonight for portions of central and north-central IN. Total snow accumulations of 4-6 inches with locally higher amounts.

- Winter Weather Advisory most other areas through midnight, total snow accumulations generally ranging from 1-4 inches.

- Snow tapering off from northwest to southeast during the evening hours.

- Extreme cold warning in effect for northwest half of central Indiana from midnight tonight through 11AM Sunday.

- Cold Weather Advisory in effect from midnight tonight through 10AM Monday for all of central Indiana.

MESOSCALE UPDATE

Issued at 513 PM EST Sat Dec 13 2025

Current KIND radar imagery depicts two more intense organized snow bands across central Indiana moving ESE with lighter snow ongoing between them. One of these snow bands stretches from Vigo county northeastward to Randolph while the other is further south from Sullivan/Knox county east to Decatur/Jennings county. These are associated with an area of stronger mid-level frontogenesis and have produced the heaviest snowfall rates of over 1 inch per hour.

Look for additional accumulations around 1-3 inches before snow tapers off during the evening. The higher 3 inch amounts should be quite confined to any locations that see repeated bands of snow over the next few hours. Colder air filtering into the region has also helped increase snow to liquid ratios which are now closer to 20:1 as opposed to 15:1 earlier in the afternoon.

Visibilities have mostly been around 1/2 of a mile to 1 miles for much of central Indiana, but visibilities as low as 1/4 of a mile have been observed in the heaviest bands. Expect these conditions to persist over the next few hours. There are hints of a third weaker band developing from Vermilion northeastward to Tipton county which will result in additional light accumulations. Will continue to monitor intensity trends with this band. Blowing or drifting snow may also become a greater concern once wind gusts pick up later this evening into tonight.

SHORT TERM (This evening through Sunday Night)

Issued at 304 PM EST Sat Dec 13 2025

Current KIND radar imagery and surface observations depict widespread moderate snowfall ongoing across much of central Indiana with a few heavier bands of snow. This is associated with increasing frontogenetical forcing ahead of an approaching shortwave and associated cold front. These moderate snowfall rates with visibilities around 1/2 to 3/4 of a miles are expected to continue through the early evening hours. Heavy snowfall rates and visibilities around 1/4 of a mile will be possible at times within any heavier more organized bands. Temperatures have also steadily dropped today due to cold air advection which is promoting higher snow to liquid ratios. Look for travel to become increasingly difficult as road conditions continue deteriorating.

Expect snow to begin tapering off from northwest to southeast during the evening once drier air filters in behind the departing system. Bitterly cold temperatures and wind chills are then expected tonight through Monday morning with arctic air ushering into the region. Near zero or single digit sub-zero temperatures and wind gusts around 15-25 mph at times may lead to wind chills as low as -15 to -25F. An Extreme Cold warning is in effect from midnight tonight through 11AM Sunday. A Cold Weather Advisory is in effect for all of central Indiana from midnight tonight through Monday morning despite slight recovery on Sunday. Another concern tonight is the potential for blowing and drifting snow from the aforementioned wind gusts, especially given high SLRs producing very light fluffy snow.

An arctic high will build in on Sunday providing mostly quiet weather and clearing skies. Bitterly cold temperatures are still expected with the potential for blowing snow mainly in the morning. Winds should relax later in the day once the surface high moves overhead. Efficient radiational cooling conditions thanks to the surface high combined with a healthy snowpack will likely support temperatures quickly dropping overnight. Look for near zero or single digit sub-zero lows. Winds chills could be as low as -10 to -18F, mainly over the northwest half of central Indiana.

LONG TERM (Sunday night through Saturday)

Issued at 304 PM EST Sat Dec 13 2025

Monday...

Quiet weather conditions are expected to begin the work week with surface ridging in place. Increasing warm air advection aloft and southwesterly flow at the surface will allow for temperatures to begin moderating. Partly cloudy skies should also aid in the warming trend with temperatures likely reaching the 20s across central Indiana.

Tuesday through Friday...

Moderate southerly breezes, courtesy of much-weaker surface high pressure lingering over the southeastern US...will maintain steady moderation through the mid-week. Afternoon highs climbing from the 30s Tuesday, to 40s Wednesday...will continue to moderate to around 50F for Thursday, with perhaps robust southerly gusts overcoming any cooling effects of scattered/numerous rain showers around the Wednesday Night-Thursday timeframe ahead of the next potent system's cold front. Overall zonal upper level pattern into the late week should prevent another arctic invasion, despite strong storm system crossing Ontario. Seasonably cool conditions expected as the long term period ends.

AVIATION (00Z TAF Issuance)

Issued at 538 PM EST Sat Dec 13 2025

Impacts:

- Snow ending this evening but blowing snow will continue tonight - VFR conditions return for tonight into Sunday - Northwest wind gusts peaking at around 20kts tonight

Discussion:

The back edge of the widespread snow is moving into the northern Wabash Valley early this evening and should sweep quickly across the terminals between 23Z and 01Z. KBMG and KIND may still have snow falling at the beginning of forecast but that will end quickly. With the onset of gusty northwest winds...blowing snow will be possible through the night at all but KBMG. MVFR stratus will linger throughout the evening but clouds will diminish overnight as the high pressure builds in.

The development of lower ceilings off of the Great Lakes may spread back into the northeast half of central Indiana towards daybreak Sunday and could briefly impact all but KHUF. Increasing subsidence through the day Sunday though will lead to the development of mostly sunny skies. Northwest winds around 10kts will continue.

IND WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory until midnight EST tonight for INZ021- 031-060>063-070>072.

Extreme Cold Warning from midnight tonight to 11 AM EST Sunday for INZ021-028>031-035>040-043>047-051-052.

Cold Weather Advisory from 11 AM Sunday to 9 AM EST Monday for INZ021-028>031-035>040-043>047-051-052.

Winter Storm Warning until midnight EST tonight for INZ028>030- 035>049-051>057-064-065.

Cold Weather Advisory from midnight tonight to 9 AM EST Monday for INZ041-042-048-049-053>057-060>065-067>072.