026
FXUS63 KIWX 251849
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
249 PM EDT Fri Jul 25 2025

.KEY MESSAGES...

- Showers and thunderstorms are expected to continue to sprout
  and move through this evening and Saturday. While the severe
  weather risk is low, heavy rain leading to flooding is a
  possibility. Another chance for showers and storms exists for
  Sunday with flooding still possible.

- Hot and humid conditions are forecast for Monday and Tuesday
  with highs around 90 degrees and dew points in the 70s. Heat
  indices over 100 are forecast for both days.

&&

.DISCUSSION...
Issued at 241 PM EDT Fri Jul 25 2025

With ridging over the southeastern US, relatively weak shortwaves
move into the area between this afternoon and Sunday afternoon.
Between 70 degree sfc dew points, 15-18C 850 mb dew points and PWATs
between 1.5 and 2.5 inches (1.5 to 2.5 SDs above normal) all allude
to a moist profile capable of heavy rain leading to flooding.
Thunderstorms will continue to be possible during the aforementioned
time frame and times of slow storm motion paired with training and
favorable MBE vectors for training/backbuilding create an
environment conducive to heavy rain and flooding. One positive is
that the area only has CPEI3 in action stage or above river-wise so
far, despite recent rain, and there`s only one line of above normal
rainfall from LaPorte to Henry county. There are two favored
locations for rain today and tonight, one south of US-24 and another
along US-6. The rainfall that occurred last Saturday from LaPorte to
Henry county may mean it takes less rainfall to cause flooding.
LaPorte, St Joseph, Starke and perhaps some of Marshall county may
need to be watched, but there is some question still around where
the supposed "storm track" resides so will stand down from a flood
watch. An area of 30 kts of effective shear depicted on the NAM late
tonight and into Saturday could allow for more instances of severe
downbursts from storms with better organization. This continued
chance for rain makes deciding on a heat advisory for Saturday
difficult with rain chances and the lingering possibility of debris
clouds allowing for pockets of cooler temperatures. Saturday still
is projected to have 70+ dew points and 850 mb temps greater than
18C, but the rain and clouds probably keep things cooler than is
needed for the heat advisory.

Substantial height rises take over Sunday as the ridge builds and
there`s some southward tendency in the surface reflection as a
shortwave dives southeastward Sunday night into Monday. This looks
like rain generally shuts off as PoPs go from 30 to 40 percent to
more like 15 to 25 percent. There is some disorganization as that
aforementioned shortwave appears to dissolve as it traverses through
the area. While some low level RH remains, the potential is there
for Monday to see renewed chances for advisory and perhaps warning
level heat and humidity. Even smaller chances for rain on Tuesday
also keeps the high heat threat around with 90 degree temps and 70
degree dew points in store. During the early week next week, the
wave guide shifts northward as the southeastern US ridge builds to
more of a sprawling south-central US ridge.

Finally, an eastern Canada upper low will be able to send cooler air
towards US Wednesday/Wednesday night as the front crashes southward
toward the area. Could see a few showers from that as the ridge
breaks down and weak shortwaves approach from the northwest. A cool
and dry period takes over to end the week and that continues into
the next weekend. CPC has a below normal precip/temp lean for the
first part of August.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1244 PM EDT Fri Jul 25 2025

Convective chances through the period remain the primary
aviation weather concern. A couple of areas of greater
convective coverage are currently expected this afternoon. One
area is expected from Lake Michigan vicinity into far SW Lower
MI/NW IN where some enhanced sfc convergence is possible given
proximity of stalled frontal zone and the potential of some weak
northerly flow off Lake Michigan. For this reason have
maintained a TEMPO TSRA mention at KSBN later this
afternoon/early evening. Confidence in thunder is slightly less
at KFWA as more vigorous convection may develop south of the
terminal where a differential heating forcing mechanism may be a
factor. Will maintain a PROB30 TSRA mention at KFWA due to the
slightly lower confidence. Showers and storms may increase in
coverage again late tonight, particularly across far northern
Indiana due to the approach of an upstream MCV across northeast
Missouri.

In terms of cigs, some pesky IFR cigs have persisted at KSBN
through midday, with sfc obs generally supporting this
preference for IFR cigs in a narrow west-east band near the
stalled frontal boundary. Diurnal mixing should continue to lift
these bases to MVFR over the next hour, before likely scattering
to MVFR after 19Z or 20Z. Additional MVFR (possibly brief IFR)
restrictions are possible later tonight in association with any
heavier showers and storms.

&&

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

&&

$$

DISCUSSION...Roller
AVIATION...Marsili