IWX issues Area Forecast Discussion (AFD) at Oct 31, 6:57 PM EDT954
FXUS63 KIWX 312257
AFDIWX
Area Forecast Discussion
National Weather Service Northern Indiana
657 PM EDT Fri Oct 31 2025
.KEY MESSAGES...
- Light lake effect rain showers are possible overnight into
Saturday, mainly for areas north of US-24.
- Temperatures remain cool over the weekend with highs in the
low/mid 50s and lows in the low/mid 30s.
- Mainly dry conditions with seasonable temperatures are
expected next week.
&&
.DISCUSSION...
Issued at 239 PM EDT Fri Oct 31 2025
An area of higher theta-e at the surface evacuates its spot downwind
of Lake MI and scoots southeast with the flow this afternoon and
into tonight allowing a drying out of the column. This is helped
along as a mid level shortwave scoots by to the south of the area
and suppression on its back side takes over. The next shortwave is
hot on its heels, though, and between 6z tonight and 18z Saturday, a
low pressure system is forecast to form over Lake MI. The general
trend will be for trajectories across the lake to back. There's
plenty of convergence on the southeast portion of the lake and some
theta-e instability as well so lake enhanced cloudiness and perhaps
a few light showers should be possible north of US-6, but the
eventual southwest winds inland should help to dry out the column
even downwind of the lake Saturday evening into early Sunday. Again,
this is helped along by the aforementioned second shortwave vacating
the Lake MI area. The continued CAA allows temperatures to drop out
around freezing Saturday night (but our growing season has ended so
no headlines will be issued for this).
Mid level ridging and surface high pressure pokes in for Sunday
helping to return the area to dry weather. WAA finally returns later
Sunday night into early Monday on the northwestern side of the now
departing surface high and out ahead of a mid level trough arriving
Monday. This already helps Sunday night lows recover back to the mid
to upper 30s, instead of around freezing, and Monday's highs to
approach 60 degrees in our southwest. The ECMWF continues to
advertise a more southern low end precipitation contour
straddling US- 30 and the NBM, which combines the GFS and CMC
and their ensembles, seems to agree. While I question the 25 to
40 percent chance advertised, cannot completely rule out a
shower this far removed from the energy within the trough.
For Tuesday, the ridge, that has been tucked into the western US
while Melissa rides north and northeastward in the Atlantic, slides
eastward and that in concert with the suppression behind the
departing trough/shortwave allows for a dry period between Monday
night and Tuesday. The flow flattens across the CONUS as the trough
that has been across the eastern CONUS departs and another waits
until Tuesday night to enter the west CONUS. At this time, a weak
shortwave (in some capacity since there's disagreement) moves
through the IL/IN area. Given the flatter flow, which should
suppress it, will maintain the dry Pops for that period.
Additionally, will allow the NBM to carry PoPs for Wednesday as
another shortwave rides west to east north of the area and we're on
the southern periphery of its precip shield. Dry weather returns for
Thursday ahead of another wave arriving for later Friday/Friday
night.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 650 PM EDT Fri Oct 31 2025
A strong upper-level low is swirling over Minnesota, dropping
southeast. On the leading edge of its vorticity, showers
developed over north-central IL and these continue to track
east. Dew point depressions of 10F or more have resulted in 6SM
-SHRA upstream. Time-height cross sections at KSBN reveal ample
low- level moisture and forcing for these showers to most
likely continue. Their trek to KFWA is unlikely with weaker
forcing noted on KFWA time-heigth cross sections.
Otherwise, clouds near +/-5k FT and a fairly steady west wind
are expected through the TAF period.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LMZ043-
046.
&&
$$
DISCUSSION...Roller
AVIATION...Brown
Source:
IWX issues Area Forecast Discussion (AFD) at Oct 31, 6:57 PM EDT---------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!
