FXUS63 KIWX 070440 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 1240 AM EDT Mon Apr 7 2025 .KEY MESSAGES... - Cooler and breezy with rain and snow showers Monday. - Initial onset snow is expected to change over to rain Wednesday and continue into Thursday. - A hard freeze is expected Monday night and Tuesday night. && .DISCUSSION... Issued at 219 PM EDT Sun Apr 6 2025 Remnant seeder-feeder forced flurries should dissipate by this evening as 850 mb moisture dissipates. Otherwise, plenty of dry air in the low levels of the atmosphere will help to keep the area mostly dry through tonight. Northwest winds and clearing sky will allow for cooler temperatures tonight as the low levels of the atmosphere cool. After this morning's temps dropped into the low 40s to mid 30s, the cooler low level temps, and potentially a period of radiational cooling before clouds fill in again Monday morning, will help bring temps down around freezing tonight. Perhaps a few areas could see frost form, but winds also appear to become excited after 6z likely stunting the maximization of cooling. Temperatures will attempt to rebound some on Monday out in front of a low pressure system, but the area of warm advection is weak and so Monday's highs will struggle to get out of the 40s. Within this atmospheric configuration, low level lapse rates will be able to quicken and near dry adiabatic allowing 25 to 35 kt low level jet to be mixed down to the surface creating an environment for 25 to 35 mph wind gusts. As a boundary moves through, rain, snow, and potentially graupel showers could be possible due to the low freezing levels and high lapse rates. The Td depressions are forecast to reach double digits away from front. Another bout of CAA follows this cold front allowing low temperatures Monday night and Tuesday night to drop below freezing - into the 20s. It's certainly on the early side, but any plants that have already come up may need to be covered. Behind Monday's potent shortwave swinging through, high pressure noses in and heights increase providing dry weather Monday night through at least Tuesday night. Some drying out of the near surface water table will be possible on Tuesday with MinRH values in the 30s and probably in the 20s as well. The weak gradient will keep gusts below 30 mph. Better model agreement exists on the rain chance for Wednesday as a warm advection wing of a low pressure system ejecting off the Rockies encroaches on the area. The quicker GFS has NAM support with the GEM in between that and the slower/shallower ECMWF. Looks like the timing of the low keeps the highest PoPs at night and the track of the low restricts the instability to south of the area. This all seems to fit the current handling of the NBM so will leave its PoPs alone. We could see some snow mix in with this as well with it coming in as temperatures are warming to and above freezing. The next chance for rain will wait until later Sunday-Monday time frame. From the cold temps on Monday, still expecting a slow warming trend through the 50s during the rest of the week to potentially seeing 60 degrees next weekend. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1238 AM EDT Mon Apr 7 2025 Cold front will arrive during the day Monday. Cloud cover was lacking with the feature, but the first of 2 CAA bursts should begin to generate some lake effect cloud cover. Not overly impressed with depth of moisture initially with fropa and Delta Ts don't drop to 13 or lower until closer to 00Z Tue. Only minor changes made to previous TAFs. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...Small Craft Advisory from 5 AM early this morning to 8 AM EDT Tuesday for LMZ043-046.&& $$ DISCUSSION...Roller AVIATION...Fisher