IWX issues Area Forecast Discussion (AFD) at Sep 20, 1:42 PM EDT229
FXUS63 KIWX 201742
AFDIWX
Area Forecast Discussion
National Weather Service Northern Indiana
142 PM EDT Sun Sep 20 2026
.KEY MESSAGES...
- Periods of rain and chances for embedded thunder lingering
into today and tonight. Localized heavy rainfall rates and
flooding will remain possible.
- A drier pattern sets up next week, though light showers and
drizzle may linger into Monday and Tuesday.
- Cooler next week with highs only in the 60s Monday through
Wednesday.
&&
.DISCUSSION...
Issued at 246 AM EDT Sun Sep 20 2026
An upstream shortwave will track east into the area today continuing
to provide a steady feed of moist isentropic ascent into a lingering
west to east oriented baroclinic zone. This will keep areas of rain,
low clouds and drizzle around for most of today into this evening.
The saving grace regarding flooding so far has been lacking rainfall
rates with the main MUCAPE axis remaining off to the southwest. This
may change however today given radar trends over northern IL
associated with the incoming shortwave that hint at an uptick in
more robust rain and chances for embedded thunder, with
model/ob/radar trends pointing to areas mainly along and north of
the US 30 corridor this morning for heavier rainfall rates and flood
impacts. A slight shift more into the southern half of the forecast
area then possible this afternoon-evening where differential heating
near the sfc portion of the front likely produces some heavier
convective elements in areas that cannot take on any more rain. Have
opted to extend the Flood Watch through 18z today, with further
extension potentially needed.
The story then for much of next week will turn to a persistent feed
of drier, cooler east-northeast flow on the southern fringe of high
pressure laying out across the northern Great Lakes. The main
moisture axis shifts south of the area Monday into Tuesday in this
regime. However, trailing shortwave energy in broad cyclonic flow
aloft may support a few flare ups in shower/drizzle activity,
especially on Monday south of US 30.
&&
.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 137 PM EDT Sun Sep 20 2026
A low level confluence zone in advance of a southward sinking
boundary aided in showers/storms this morning across northern
Indiana. A lull in greater rain shower developed late
morning/early afternoon but an advancing convectively enhanced
short wave from northern Illinois is associated with another
area of rain that will overspread terminals this afternoon. The
instability gradient remains parked roughly along the US Route
30 corridor, so cannot completely discount some scattered
convection and some thunder potential at KFWA for a time in the
20Z-23Z timeframe, but confidence in this scenario is somewhat
low. IFR cigs are expected at terminals through this evening
with eventual north to south improvement late evening into
Monday morning as baroclinic zone sinks southward and low level
dry air advection overspreads southern Great Lakes. MVFR cigs
will likely persist into Monday morning at KFWA however.
Deepening northeast flow and some increase in mixed layer with
cold advection will support northeast gusts to around 20 knots
at times.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Flood Watch until 2 PM EDT /1 PM CDT/ this afternoon for
INZ005>009-012-014-015-017-018-023>027-032>034-103-104-
116-203-204-216.
OH...Flood Watch until 2 PM EDT this afternoon for OHZ015-024.
MI...Flood Watch until 2 PM EDT this afternoon for MIZ078>080-177-
277.
MARINE...None.
&&
$$
DISCUSSION...Steinwedel
AVIATION...Marsili
Source:
IWX issues Area Forecast Discussion (AFD) at Sep 20, 1:42 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!
