textproduct: Northern Indiana

KEY MESSAGES

- Wind chills of -5 to -15 tonight into Monday morning.

- Warming trend Tuesday through Thursday with highs up near 50 by Thursday.

- Periods of rain on Thursday, followed by windy conditions and briefly cooler temperatures into Thursday night and Friday.

DISCUSSION

Issued at 129 PM EST Sun Dec 14 2025

~1042 hPA arctic high pressure center over far west-central IL will weaken southeast through the lower OH Valley and central Appalachians tonight into Monday under building heights aloft. This will allow low level flow trajectories to back west into this evening, and to the southwest later tonight and Monday. Lingering lake effect snow showers/flurries will taper off as a result this afternoon and evening with little additional accum/impact near Lake MI. Lighter winds on the edge of the sfc high and eventual northward lift and erosion of lake clouds should allow for decent radiational cooling over fresh snow, with lows near zero in many locations. Temps then likely level out into early Monday as light southwest flow develops. Whether wind chills can settle solidly into advisory criteria (-15 to -24F) for a time later tonight into Monday morning remains highly uncertain. A model consensus and HREF probs generally favor wind chills in the -5 to -15F range for most. Have opted to hold off on a CW.Y as a result, but will continue to message the cold in other products.

A 40-50 kt LLJ develops late tonight into Monday in response to a tightening low level height gradient behind the departing high and a weak sfc trough tracking east into the northern Great Lakes. Southwesterly gusts reaching 25-30 mph within this feature during the day on Monday could result in patchy blowing/drifting in rural areas, especially near Lake MI and over the southern half of the forecast area where several inches of snow fell yesterday.

A more zonal flow regime will bring relatively quiet weather and warming temperatures Tuesday into Wednesday. A buckle in this more progressive, flattened, flow does send a stronger cold front through around Thursday with periods of rain likely. Windy and briefly colder behind this system then into Thursday night and Friday.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 546 PM EST Sun Dec 14 2025

VFR conditions expected through the TAF period for KFWA. For KSBN lake effect snow showers will continue to keep MVFR to IFR vsbys until 05z Mon before more veering of the winds ahead of low level ridging pushing southward into the area shuts off the lake effect snow showers for the KSBN terminal area. Southwesterly wind gusts for KSBN after 12z Mon and through 19z Mon will approach 24 knots which could cause some temporary lowering of visbys in blowing/drifting of fallen snow, however at this time confidence is low in this so did opt to leave mention out of the TAFs at this time.

IWX WATCHES/WARNINGS/ADVISORIES

IN...None. OH...None. MI...None. MARINE...Small Craft Advisory until 10 PM EST this evening for LMZ043- 046. Gale Warning from 5 AM to 1 PM EST Monday for LMZ043-046.