406
FXUS63 KIND 230126
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
926 PM EDT Fri May 22 2026

.KEY MESSAGES...

- Rain spreads north across much of central Indiana today with
  continued below normal temperatures. Some potential for
  localized flooding in SE portions of central Indiana this
  evening and tonight.


- Rain chances continue through the holiday weekend into next week,
  but temperatures will become above normal for much of the period.

&&

.FORECAST UPDATE...
Issued at 924 PM EDT Fri May 22 2026

Scattered to numerous showers are ongoing across central Indiana as
a weak low pressure system continues lifting north this evening.
Showers will be possible at times through the night with widespread
low clouds. Look for this to keep temperatures mild, in the upper
50s to low 60s. Expect northeasterly surface flow to become
northerly and then westerly late tonight into Saturday morning.

A Flood Watch remains in effect for Jackson and Jennings county
through 5AM Saturday due to the potential for a brief period of
moderate to heavy rainfall later tonight over saturated soils.
Deeper moisture advecting northward along with elevated instability
and an associated LLJ will help promote these heavier rainfall
amounts over far southeast portions of central IN. Thunder is
unlikely overnight across much of central IN, but E/SE counties
still have a chance for isolated thunderstorms through the night as
they will be in the warm sector of the aforementioned surface low.

&&

.DISCUSSION (This evening through Friday)...
Issued at 128 PM EDT Fri May 22 2026

Today and Tomorrow...

For this weekend, central Indiana will be within an active
portion of a subtropical jet streak, of which will aid in the
development of shortwaves and therefor multiple chances for
rainfall. The first of which is passing through today and tonight.
This particular shortwave is ejecting out of the Gulf with
abundant moisture throughout. The enhanced diabatic processes of
this gulf low will aid in low level pressure depletion over the
next 12-24 hours, resulting in a more mature surface low late
today and tonight.

Initial rainfall is expected to be associated with weak frontal
convergence in the 850-700mb layer as dry NE flow interacts with
very moist SE flow over the Ohio Valley. Current radar and IR
imagery showcase this well with widespread rain along the OH/IN
border quickly surging northward. This rain is expected to be in
the Indianapolis area around 2PM Friday afternoon. Consistent
light to moderate rainfall is expected to be the norm for most of
the afternoon and early evening over the SE half of central
Indiana with the one exception being a low chance for
thermodynamically enforced convection over far southern central
Indiana. However, late this evening and tonight, slantwise
instability in the front right quadrant of the advancing low will
aid upward lift, likely promoting a period of moderate to heavy
rainfall and isolated lightning production.

When all is said and done, total rain amounts will vary across the
region, but generally those S/E of I-69 are expected to get 0.5-1.5"
with lesser amounts to the N/W. The CSI banding potential overnight
could lead to narrow corridors of 2-3 inches, of which will create
a low end flooding threat given already saturated soils from
prior rainfall.

A quasi stationary boundary will linger north of central Indiana
following the passage of the wave. Along and south of this boundary,
there will be enough moisture and instability for isolated
convection to occur, but the only forcing will likely be
associated with microscale fluctuations and weak synoptic lift
within the entrance region of the subtropical jet. The current
expectation is for a large majority of central Indiana to remain
dry tomorrow, with a few areas seeing a brief shower or storm in
the morning to early afternoon.

Sunday...

The next shortwave will arrive from the West late Saturday night
through Sunday. Moisture with this wave passage will not be as
abundant, but with antecedent dew points already in the mid to upper
60s, there should be enough instability for convective initiation to
occur as the wave passes through. High resolution guidance is mixed
on wave timing as of 12Z Friday. Specifically for Indianapolis there
is a range from 15-18Z start time and a 20-00z end time for storm
chances. Given weak shear within the passing wave along with 500-
1000 J/kg of SBCAPE, isolated strong to severe thunderstorms can
also not be ruled out during this timeframe. After the wave passes
through Sunday late afternoon/evening modest subsidence should
quickly reduce rain chances with dry weather expected Sunday evening
and night.

Temperatures will likely be slightly warmer Sunday with weak
southerly flow returning, but will greatly depend on where
convection and related cloud cover occurs. General expectation is
for afternoon highs in the upper 70s.

Memorial Day onward...

Following Sunday`s wave passage, amplified ridging will start to
build over the Southern Appalachia to the Ohio Valley regions
decreasing upper level forcing. However, in the lower levels, a
stagnant boundary is expected to develop near the Ohio River. Weak
forcing and remnant moisture along the boundary will likely induce a
scattered showers Monday through Tuesday over this same area. Areas
to the north (a majority of central Indiana) are expected remain
dry. Temperatures look to be slightly above normal with some
influence from the ridging to the east expected.

Forecast confidence decreases significantly Wednesday onward as
ensembles introduce another wave entering the region from the
west. Generally, this will increase PoPs for Wednesday, but
specifics for this wave passage are still highly variable.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 742 PM EDT Fri May 22 2026

Impacts:

- Widespread IFR conditions through tonight with the potential for
  LIFR conditions at times, primarily near IND/BMG
- Showers possible through tonight along with MVFR visibilities from
  BR
- Ceilings improving to MVFR by midday Saturday and eventually VFR
  late Saturday

Discussion:

SHowers have overspread central Indiana as a low pressure system
moves in. Widespread IFR ceilings and showers will be common through
tonight though coverage of showers should diminish late overnight.
MVFR visibilities are likely due to showers and BR at times tonight.
KLAF will take longer to reach IFR and will have the lowest chances
for showers.

Low ceilings will persist into Saturday with improvement to MVFR by
midday Saturday and eventually VFR late Saturday afternoon or into
the evening. Winds will stay easterly throughout the evening and
tonight before quickly switching to northerly and then westerly late
tonight into tomorrow morning.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 5 AM EDT Saturday for INZ071-072.

&&

$$

UPDATE...Melo
AVIATION...Melo
DISCUSSION...Updike