028
FXUS63 KIWX 180148
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
848 PM EST Mon Nov 17 2025

.KEY MESSAGES...

-Rain expected tonight into Tuesday, mixing with or changing
 over to all snow Tuesday morning for areas mainly north of US
 30. Areas north of US 6, especially along and east of I 69,
 could see minor snow accumulations of around 1 inch or less.
 Travel with caution for the Tuesday morning commute as there
 could be slick slush or snow covered roads. Rain showers are
 likely in the afternoon as temps rise into the mid-upper 30s
 and low 40s.

-Wednesday will be dry with highs in the 40s. There is a 30-65
 percent chance of rain showers Thursday through Saturday.

&&

.UPDATE...
Issued at 848 PM EST Mon Nov 17 2025

The overall nature of going forecast has been maintained this
evening, with precip type and winter precip accumulations
remaining the primary short term forecast challenge.

An initial modest low level theta-e gradient just downstream of
mid level ridge will shift slightly eastward through late
evening. Despite some increases in low level moisture with this
feature, subcloud layer in lowest 6-8k feet remains relatively
dry. Have received a few reports of some light rain/sleet with
this advective wing forcing, but would suspect precip amounts
with this feature given moisture limitations will be a trace to
perhaps a hundredth of an inch.

Primary precip chances still appear more delayed until late
tonight into early Tuesday morning. After 09Z, the nose of a low
level jet downstream of Central Plains upper low will begin to
impinge on NW Indiana and eventually to south central Lower
Michigan in the 12Z-15Z timeframe. Some upper jet support also
comes into play by this time as a compact upper jet streak
(100+ knots per Dodge City, KS 00Z RAOB) progressing through
the base of this trough noses across the southern Great Lakes.

Precip type forecasting late tonight into early Tuesday remains
quite a challenge given low level wet bulbing to a near
isothermal layer near the freezing mark up to about 850 mb. To
further complicate things, primary snow growth zone is highly
elevated with -10 deg C level at approximately 15k feet with
marginal RH in terms of saturation at this level suggesting some
light freezing rain potential. These marginal temps in snow
production layer, and weak warmer layer potential with
isothermal low level layer really makes the full gamut of precip
types possible for a time late tonight into early Tuesday across
far NE Indiana/SC Lower Michigan/far NW Ohio. Still feel that
impactful freezing rain potential is on the lower side given
marginal near sfc wet bulbs and better drying of the snow
production layer not occuring until after 14Z when near sfc wet
bulbs may tend to recover. A period of wet snow still appears
possible across the far northeast late tonight/early Tuesday
despite less than ideal snow:liquid ratio thermal profiles and
the deep near freezing isothermal layer. One compensating factor
that could allow for some slushy 0.5 to 1+" snow accumulations
across the northeast is the potential for some aggregation given
the deep,moist profiles. Some travel impacts are possible, but
current scenario still points to more of a minor impact setup.

Only tweak to previous forecast was to add slight chance PoPs
with initial warm advection wing precip this evening, and to
slightly slow west-east advance of higher PoPs overnight.

&&

.DISCUSSION...
Issued at 208 PM EST Mon Nov 17 2025

A quick moving system will move from the Midwest into the Great
Lakes region tonight into Tuesday. Initially starting as mainly
rain showers a frontogenesis band associated with the system
will allow a quick change over from rain showers to a rain/snow
mix and ultimately all snow for areas north of US-30 with even
some minor accumulations, 1 inch or less, mainly north of US-6
along and east of I-69. For our far northeast parts of the CWA
there is a low chance of some freezing rain on the onset but
with ground temperatures still fairly warm and any freezing rain
occurrence being very brief did opt to leave out of the
forecast grids but did want to mention here as there is a
chance.

A zonal flow aloft on Wednesday and Thursday will allow for
some slight synoptic warming with highs by Thursday getting into
the 50s across the area. By Friday another system this time
slightly warmer than tonights system originating from the Texas
Panhandle will bring another chance of rainfall beginning
Thursday night through Saturday. Looking to see a little bit
more rainfall with this system as being centered further south
will have access to a bit more moisture to work with. Highs
Friday through Sunday will range in the upper 40s to mid 50s.
Fairly close to seasonal norms.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 705 PM EST Mon Nov 17 2025

Overall, not much change in forecast thinking with the 00Z TAFs.
A low level moisture gradient across the western Great Lakes
will continue to shift eastward this evening in advance of an
upper low moving across the Central Plains. Radar data indicates
some weak elevated returns across southern Lake Michigan at the
leading edge of this theta-e gradient, but dry low levels
initially will take some time to saturate before measurable
precip becomes an issue. Strongest low level moisture
transport/isentropic lift should not arrive until after 06Z. It
still appears as though terminals should have mainly liquid
precip type with better chance of rain/snow/sleet mix across
extreme NE IN/south central Lower MI. Trend to MVFR cigs is
expected after daybreak Tuesday, with cigs likely dropping below
2k feet mid/late morning. The potential does exist for some IFR
cigs late morning/early afternoon period, but confidence is too
low for inclusion. Have carried rain as prevailing weather type
late tonight through Tuesday morning, but additional scattered
showers are possible during Tuesday afternoon as cold core
upper low associated with upper trough tracks across the area
with a pocket of elevated instability.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.

&&

$$

UPDATE...Marsili
DISCUSSION...Andersen
AVIATION...Marsili