FXUS63 KIWX 121118 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 618 AM EST Fri Dec 12 2025 .KEY MESSAGES... - Dry for most areas into early Saturday. Some lake enhanced snow showers are possible along the shores of Lk MI with generally an inch or less accumulation. - Period of light snow Saturday afternoon (accumulations 1 to maybe 3 inches), transitioning to mainly lake effect snow showers Saturday night into Sunday (additional 1 to 3 inches NW). - Much colder air arrives Saturday, lingering into Monday. Wind chills of -15 degrees F or lower are likely Sunday morning southwest of Route 30. - Above freezing temperatures return Tuesday through Thursday with chances for rain. && .DISCUSSION... Issued at 314 AM EST Fri Dec 12 2025 Back edge of light snow, associated with the first of several clippers was moving across eastern IL. Far SW parts of the area (mainly portions of White and Cass county) did see some snow and based on INDOT cameras probably received at least a few tenths of new snow. Dry conditions will dominate most areas through Saturday morning as the main energy with the active northern stream trough passes mainly to the north of the area. A brief window of W to WNW flow will setup, with marginal Delta Ts and limited moisture/inversion heights resulting in a period of light snow tonight into early Saturday for portions of LaPorte, Berrien and maybe Cass counties. Accumulations, if any, should be an inch or less. Stronger clipper system and associated punch of arctic air, will take aim on the area late Sat morning into the afternoon hours with a burst of light synoptic snowfall. Overall accumulations look to be on the order of 1 to 2 inches (maybe a bit higher south of US-24). As 850 mb temps plummet to -20 C or lower Saturday night through Sunday night, a more pronounced lake response should commence with moderate lake induced instability and inversion heights 8-10 kft. Currently leaning towards potential accumulations of at least 1 to 3 and some potential for higher amounts depending on the final fetch. Headlines may be needed in this time frame, but confidence not high enough to hoist anything this far out. Lows in the single digits (above and below zero) are expected Saturday night, with the coldest temperatures across SW areas away from the lake effect clouds and precip. Sub zero wind chills are still in store for the entire area with -5 to -10 F under the cloud cover and a sharp gradient of -15 to -20 F where skies are clear. A wind chill advisory will likely be needed for these areas in the next issuance or 2. Skies begin to clear out across a larger area Sunday night into early Monday with overnight lows -5 to +5 F and wind chills roughly -10 to -15 F. A more pronounced shift in the patter will commence Monday night and persist through the end of the period with highs climbing above freezing during the day to allow for melting of the snowpack across the area. Aiding in the process with be a few chances for rain. && .AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 618 AM EST Fri Dec 12 2025 Brief MVFR is possible during the next two hours but a period of VFR is anticipated by late morning through early afternoon as we reside in between systems. Another shortwave then arrives overnight with more MVFR (fuel alternate) stratus likely. Some lake-enhanced snow is also possible at KSBN tonight but westerly flow and northward displacement of better forcing will likely keep snow confined to Michigan. Gusty northwest winds are anticipated by early Sat morning behind the cold front. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...Small Craft Advisory from 10 PM this evening to 10 PM ESTSunday for LMZ043-046. && $$ DISCUSSION...Fisher AVIATION...AGD