990
FXUS63 KIND 081338
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
938 AM EDT Wed Jul 8 2026

.KEY MESSAGES...

- Generally dry today with temperatures in the mid to upper 80s,
  low chance for rain in southern Indiana

- Strong to severe storms and flash flooding possible late Thursday
  into Thursday night

- Additional rain Friday through the weekend with pockets of
  flooding

&&

.FORECAST UPDATE...
Issued at 937 AM EDT Wed Jul 8 2026

The forecast remains in good shape with only minor adjustments
needed. Current KIND Radar imagery depicts isolated showers and
storms south of the forecast area with quiet weather conditions
across central Indiana. The isolated convection is associated with a
weak mid-upper level disturbance which will crawl northward during
the day. This may support isolated showers or storms over far
southern counties by the afternoon. Otherwise, expect weak surface
high pressure to remain the dominant weather feature promoting quiet
weather for most areas. Look for another warm, but near seasonal day
in the mid 80s.

&&

.DISCUSSION (Today through Tuesday)...
Issued at 123 AM EDT Wed Jul 8 2026

Overview.

Dry and pleasant weather is expected for today with highs topping
out in the mid to upper 80s. On Thursday, a strong cold front
will move into the region, bringing a risk for severe
thunderstorms and heavy rainfall that could cause flash flooding
Thursday night. This front will then stall over the area, keeping
chances for showers and storms in the forecast from Friday through
the weekend and into early next week, leading to the potential
for flooding with total rainfall amounts of 2 to 4 inches.

Today through Thursday.

The broader synoptic pattern today features mid-level ridging
centered over the Ohio Valley that will gradually suppress southward
as a northern stream shortwave trough digs across the upper Great
Lakes. At the surface, high pressure positioned over the eastern
Great Lakes will maintain a dry easterly to southeasterly low-level
flow across central Indiana. Forecast soundings exhibit a notable
mid-level subsidence inversion along with deep dry air. This dry
airmass and large-scale subsidence will inhibit convective
development today, keeping the entire forecast area dry with
afternoon high temperatures rising into the mid-80s.

The synoptic pattern transitions rapidly on Thursday as a northern
stream shortwave trough deepens over Ontario, driving a surface cold
front south-southwestward toward the area. Ahead of this boundary, a
robust low-level jet will advect an anomalously moist, tropical
airmass northward. PWAT values are modeled to surge toward 2.00 to
2.25 inches, which sits well above the 90th percentile for early
July. HREF and ensemble guidance indicates rapid destabilization
Thursday afternoon ahead of the front, with MLCAPE expanding to 1500-
2500 J/kg. Convective initiation is expected along and ahead of the
front by late Thursday afternoon and evening. While deep-layer
shear remains modest at 25-35 knots, linear forcing along the
front will support organized multicell clusters and transient
supercell structures. Damaging downburst winds and isolated severe
hail represent the primary convective hazards.

A flash flooding threat will develop Thursday night. As the
surface front slows down and aligns parallel to the mid-level
westerly flow, Corfidi vectors indicate a high potential for cell
training. Warm-cloud depths exceeding 12,000 feet will optimize
warm-rain processes, yielding exceptionally high precipitation
efficiency. Localized rainfall rates exceeding 2 inches per hour
are anticipated, capable of producing widespread flash flooding
and areal flooding across central Indiana overnight.

Friday Through Tuesday.

From Friday through the weekend, the surface frontal zone is
forecast to become quasi-stationary across the Ohio Valley as it
encounters a flat sub-tropical ridge anchored over the Gulf Coast
states, blocking its southward progression. Within this weak
steering regime, successive low-amplitude mid-level shortwaves will
track along the frontal zone, interacting with the lingering
tropical moisture reservoir where PWATs remain elevated between 1.75
and 2.00 inches. This setup will support daily rounds of convective
clusters and multi-cell arrays through Sunday.

Medium-range ensemble guidance (GEFS and EPS) exhibits high
consensus regarding a prolonged, heavy rainfall footprint across the
Ohio Valley due to this stalled boundary. Probabilistic guidance
indicates a 60-80% chance of widespread total rainfall exceeding
2.00 inches across central Indiana through Sunday evening. Within
corridors experiencing persistent convective training or repeated
cell tracking, probabilistic clusters indicate a 30-40% chance of
localized totals exceeding 4.00 inches. Given the saturated
antecedent conditions expected from Thursday night`s convection,
this additional rainfall will sustain and exacerbate risks for river
flooding and ongoing areal flooding through the weekend.

The unsettled pattern will gradually transition into early next week
as the main upper-level trough shifts into eastern Canada, allowing
northwest flow aloft to develop over the Midwest. While the primary
stalled frontal boundary will diffuse or push slightly south of the
state, embedded shortwaves within the northwest flow will maintain
daily chance-level probabilities (30-50%) for showers and
thunderstorms. Temperatures throughout the period will remain near
or slightly below seasonal normals in the low to mid-80s due to
widespread cloud cover and precipitation, though high ambient
dewpoints in the lower 70s will maintain elevated humidity levels.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 542 AM EDT Wed Jul 8 2026

Impacts:

- None

Discussion:

VFR conditions expected through the TAF period outside of brief MVFR
vsbys at BMG through 13Z. Diurnal cu is expected to develop towards
15Z with coverage expected to remain FEW to SCT. This cu will
dissipate towards 00Z with high cloud coverage increasing through
the night tonight. Winds will generally be light and variable
through the TAF period, predominately out of the north through
daybreak, then west to southwest during the day.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...Melo
AVIATION...White
DISCUSSION...White