Portage, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

966
FXUS63 KIWX 222347
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
647 PM EST Mon Dec 22 2025

.KEY MESSAGES...
- Rain and drizzle developing tonight (20-40% chance).

- Trending warmer in the days ahead with highs near 50 degrees
  as early as Wednesday and Thursday.

- 60-80% chance of rain Wednesday night and Thursday night.

&&

.DISCUSSION...
Issued at 203 PM EST Mon Dec 22 2025

A weak upper-level impulse streaking across the upper Great Lakes
this morning failed to produce any precipitation across far southern
Michigan; abundant dry air proving too much to overcome. A warm
front is noted across the Tennessee valley and this will
gradually lift north as low-level flow become southwesterly
encountering a southern US ridge of high pressure. This warm
front will allow for low-level saturation to improve overnight.
Paired with the departing right-entrance region at 500 mb, there
remains a chance for light rain and drizzle tonight. Forecast
soundings depict a sufficiently mild profile to negate any
winter weather concerns. Incoming high pressure ultimately ends
any wet weather as Tuesday progresses but a low- level inversion
threatens to keep clouds locked in place until late afternoon.

A progressive upper-air pattern in the days to come presents
forecast temperature challenges but generally mild conditions and
periodic chances for rain. Canadian high pressure centered over the
upper Great Lakes on Wednesday and Thursday had resulted in large
temperature discrepancies which are finally beginning to narrow.
Return southerly flow on Thursday as the high shifts east may
permit a few sites to reach the mid-50s south of US 24, but it
otherwise seems that highs near or just shy of 50 will be the
norm; good for a top-10 warmest Christmas at Fort Wayne. There
is a chance of rain Wednesday night as warm front attempts to
lift in.

The late-week and weekend forecast continues to feature a
chance of rain Friday as an upper-level wave streaks through.
This is followed by a deeper low moving through Ontario on
Sunday, bringing the risk of rain changing to lake effect snow
and sharply cooler conditions.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 645 PM EST Mon Dec 22 2025

A low level warm frontal feature will lift across northern
Indiana overnight. Broad low/mid level isentropic upglide will
accompany this warm front, with strongest isentropic upglide
expected roughly in the 04Z-08Z timeframe. Low level moisture
is marginal in nature initially, but positive low level theta-e
advection over the next several hours and approach of small
scale vort max across western Iowa could allow for a few showers
to develop across northeast Indiana early overnight hours. Have
continued trend of top-down saturation process this evening,
eventually leading to MVFR cigs below 2k feet overnight into
early Tuesday. Greater confidence in IFR conditions still
exists at KFWA which should be inline for best near sfc
northward moisture transport, but would suspect that a brief
period of IFR cigs is also possible at KSBN with onset of low
level CAA Tuesday morning. Some patchy drizzle will be possible
late tonight into early Tuesday due to shallow nature of
moisture profiles, but enough low level drying should occur by
late Tuesday morning to end drizzle potential. Did include a
brief mention of LLWS overnight tonight at KFWA which should be
in a more favorable proximity to a 30-40 knot westerly low level
jet for a time in the 06Z-12Z period.

&&

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

&&

$$

DISCUSSION...Brown
AVIATION...Marsili