IWX issues Area Forecast Discussion (AFD) at Sep 9, 12:30 PM EDT373
FXUS63 KIWX 091630
AFDIWX
Area Forecast Discussion
National Weather Service Northern Indiana
1230 PM EDT Wed Sep 9 2026
.KEY MESSAGES...
- A warm and more humid airmass will be in place into early
Thursday. Cloud cover and precipitation may cause large
variations in temperatures Wednesday.
- There is a 30% to 60% chance of showers and thunderstorms
Wednesday through early Thursday morning. There is a marginal
risk for isolated severe storms between 3-9 pm ET this eve,
mainly along and south of US 24. Heavy rain, lightning, and
isolated damaging wind gusts are the primary threats in the
strongest storms
- There is a moderate swim risk for Northern Berrien County, MI
beaches along Lake MI today, and for all of Berrien County, MI
and La Porte County, IN Thursday. Breaking waves and currents
are expected.
&&
.UPDATE...
Issued at 1025 AM EDT Wed Sep 9 2026
Area of rain/rain showers, extending from central Lower MI to
west central IL, is making very slow progress SE. While a few
lightning strikes have been noted to our NW, majority currently
reside well to the west. Much of this area appears to be behind
the pre-frontal trough which is now a a bit more apparent on sat
and radar as a broken line of showers from Coldwater to Warsaw
and Logansport. Hi res models not handing this at all and even
the larger area of rain to the west is causing challenges. At
this point, no major changes to the grids as we monitor the
trends of both these areas. 13Z SPC SWODY1 left the marginal
risk unchanged. If any severe threat occurs, it would most
likely be tied to the pre-frontal trough itself with lesser
chances in the area of precip behind it.
&&
.DISCUSSION...
Issued at 428 AM EDT Wed Sep 9 2026
A pre-frontal trough will cross the area from west to east today,
bringing chances for showers and a few thunderstorms. SPC has areas
generally along and south of US 24 in a marginal risk for isolated
strong-severe storms, but confidence in this occurring is low. If
stronger storms do develop, they will not be widespread. The main
threat would be damaging winds, frequent lightning, and heavy
downpours. Area in the marginal risk should have better instability
as the feature moves through towards the mid-late afternoon hours
(1500 J/kg), with about 20-30 knots of 0-6 km AGL shear (better
shear arrives in the late afternoon, but it's disjointed from the
better instability). Plenty of moisture around with dewpoints in the
60s, 70s. High temperatures will be in the low to mid 80s
along/north of US 24, and the upper 80s further south. Heat indices
in the southern areas could reach into the low-mid 90s during peak
heating this afternoon.
Southerly winds will strengthen slightly out of the southwest
through the day, with a period of westerly flow possible briefly
behind the passing trough. Waves on Lake MI around St. Joseph,
MI northward may climb to around 2-3 feet by mid afternoon, and
around 1-2 feet further south. Have a moderate swim risk for
Lake MI beaches along the Northern Berrien County, MI shoreline
today (including Silver Beach County Park and Tiscornia Park).
Waves reach around 2-3 feet for Southern Berrien County, MI and
La Porte County, IN by Thursday as well with northerly flow
picking up slightly tonight into Thu. Have a moderate swim risk
for both counties accordingly. Today, a moderate to strong south
to north flowing longshore current is expected, which will lead
to strong structural currents on the south side of
piers/breakwalls. Rip currents are possible within the sandbars.
All current types are possible on Thursday.
Becoming cooler and less humid behind a passing cold front on
Thursday. Chances (30-50%) for showers and thunderstorms remain
mainly along/south of US 30 during this period. Severe weather is
not expected. It's possible that the front reaches further south at
a quicker pace than currently forecast, which would reduce pops for
Thursday all together. Highs will be around 80 degrees, with lows in
the 50s, low 60s.
While we will still have weak upper trough overhead on Friday (some
models suggest more riding), surface high pressure remains in
control with easterly flow in the low levels. Most of the guidance
remains dry in this period, with the exception being the far south
where some models produce light precip. Left out for now given low
confidence. Highs will be around 80 degrees, with lows in the 50s,
low 60s.
Highs warm back into low-mid 80s for the weekend into Monday, with
an upper level ridge Friday night becoming more zonal with time,
leaving us susceptible to shortwaves kicking off showers and storms.
Have low chances (20-30%) each day through the period. Better
potential (30-50% chances) arrive mid-late week as an upper level
low drops into the northern plains and a broad surface low
developing near IA deepens and lifts into Ontario/Quebec. This will
bring a cold front through sometime between Tue-Wed. Highs remain in
the upper 70s, low-mid 80s, coolest Wednesday.
&&
.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1225 PM EDT Wed Sep 9 2026
Showers and a few isolated pockets of thunder developed earlier
this morning across northwest Indiana. Precipitation has been
somewhat slow to develop along a pre-frontal trough, with the
main cold front still lagging behind back in northern Illinois.
Expect additional scattered showers and storms with mainly low
end VFR to high end MVFR ceilings and visibilities prevailing
this afternoon. The main axis of instability is east of I-69 and
south of US 24, which is where I would expect any thunderstorms
to occur today with potentially gusty winds. Rain should wrap
here around 20Z at KSBN and around 22Z at KFWA. As the cold
front passes through, winds shift from west at around 10 kts to
light out of the northwest. Light winds continue overnight with
VFR ceilings gradually clearing. A mainly dry day is expected
Thursday; a few showers and storms are possible south of US 24
but have kept KFWA dry for now.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.
&&
$$
UPDATE...Fisher
DISCUSSION...MCD
AVIATION...Johnson
Source:
IWX issues Area Forecast Discussion (AFD) at Sep 9, 12:30 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!
