557
FXUS63 KIND 200245
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1045 PM EDT Fri Jun 19 2026

.KEY MESSAGES...

- A few showers are possible late tonight and Saturday. Isolated TS
  are possible Saturday afternoon generally along the I-70 corridor.

- Widespread rain will be around for Sunday into early Monday, with
  heavy rain and isolated severe storms possible.

- Below normal temperatures will continue for much of the period.

&&

.FORECAST UPDATE...
Issued at 1042 PM EDT Fri Jun 19 2026

Updated the forecast to match current observations. There is a
chance of scattered light rain during the early morning hours as a
weak system pushes through the region. Winds will also continue to
weaken through the night before picking back up to around 5-10 mph
by tomorrow afternoon.

&&

.DISCUSSION (This evening through Friday)...
Issued at 331 PM EDT Fri Jun 19 2026

Tonight through Saturday Night...

A shortwave trough over the upper Midwest will move SE along the
fringes of the longwave trough over eastern CONUS/Canada into Great
Lakes tonight. Associated with this system moderate mid level WAA
has aided in moderate FGEN forced bands of light to moderate showers
across the Siouxland region. Elevated instability is meager (under
200 j/kg) with generally moist adiabatic mid level lapse rates so no
TS is expected. However progressive nature of this shortwave and
attendant FGEN forcing should support these showers moving into
central Indiana overnight. Granted the paucity of low level moisture
should keep it mainly of the sprinkle variety tonight into early
Saturday.

With daytime heating and some augmentation of the boundary layer
moisture owing to the precip fall from the mid level showers and
advection of higher BL moisture from the west, expectation is that
there may be another round of showers and possibly isolated TS
during Saturday afternoon along and ahead of a weak confluence
boundary moving southward in the wake of the mid level shortwave
trough. Current forecast soundings from the NAM are much more
aggressive in moistening BL moisture with forecast soundings showing
around a +13C dewpoint at 850mb. This would generate around 750 J/KG
of SBCAPE by 21Z. Believe the drier majority of other model sounding
solutions limited surface based CAPE to only a few hundred J/KG
seems more likely. As a result only carrying a chance of TS

Any convection should diminish quickly around sunset with loss of
daytime heating and negligible forcing.

Sunday and Monday...

A shortwave trough over northern CA will shift eastward into the
Rockies by Saturday. Lee cyclogenesis developing ahead of increasing
mid level flow over the Rockies will support strong convergence and
a significant thunderstorm complex over the central high plains by
Saturday night. This cluster is expected to shift eastward into the
lower plains by Sunday morning supported by a 30-40 kt llj. Activity
is expected to continue to propagate along both synoptic and a
mesoscale augmented baroclinic zone extending into eastward from the
MS valley into central Indiana. Current indications are that
sufficient instability will develop by Sunday afternoon ahead of
this system (whether in an MCV decayed state or ongoing strong
convection) will support vigorous convection just east of the MS
river into central Indiana late in the afternoon lasting into the
evening/early overnight. SPC`s Marginal Risk for Day 3 seems
appropriate given there exists some uncertainty in the timing of
convective line/cluster. However, if activity reaches central
Indiana slightly faster, than forecast area could easily be upgraded
to a Slight or potentially even and enhanced risk with all hazards
possible. In addition to the threat for severe weather, PWATs will
increase to near climatological 90th+ percentile for late June. As a
result, depending on where the baroclinic zone sets up, the
potential for heavy rainfall from 2-3 inches is increasingly looking
likely into Sunday night. WPC Day 3 Slight Risk for Flash Flood
seems very reasonable given above normal soil moisture across most
of the area from recent heavy rain events.

Precip will come to an end fairly quickly early Monday owing to the
unseasonably strong mid-upper jet across our Latitude. Surface High
pressure and residual weak CAA clouds should keep highs in the 70s
much below normal of mid 80s for the first day of Summer.

Tuesday and beyond...

Tuesday is expected to be dry and cool with high pressure building
southward from the northern Great Lakes. Medium Range guidance
suggests that a couple of low amplitude shortwave trough will move
across the region from Wednesday into Friday. Confidence in the
strength and timing of these systems remains low, so will keep
broad brushed lower PoPs.

The continued longwave trough pattern centered over eastern North
America will keep temperatures below normal through this period and
into early next weekend.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 810 PM EDT Fri Jun 19 2026

Impacts:

- NW winds above 10 kt to start then becoming light overnight
- VCSH tonight early Sat morning

Discussion:

VFR conditions are expected through the period.

Overnight a weak storm system over the upper Midwest will move SE
across central Indiana. With this system there will be increasing
mid level clouds and scattered very light showers could develop.
Carrying VCSH to account for this activity.

For tomorrow, skies will mostly clear out by mid morning with
passing of this system. West/Northwest winds will increase by midday
to 7-12 kts.


&&

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

$$

UPDATE...KF
AVIATION...KF
DISCUSSION...Crosbie