397
FXUS63 KIND 221348
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
948 AM EDT Sun Mar 22 2026

.KEY MESSAGES...

- Near record highs today with readings in the 80s (except across
  our northern counties).

- Showers and thunderstorms expected this evening, strong to
  severe storms possible with large hail and damaging winds being
  the primary hazards.

- Cooler on Monday with a warming trend through the workweek.

- Showers and thunderstorms possible late Thursday.

&&

.FORECAST UPDATE...
Issued at 948 AM EDT Sun Mar 22 2026

No major changes in forecast thoughts for both the afternoon record
warmth and evening severe weather with conditions generally evolving
as expected. Temperatures continue their rapid rise with several
sites already showing low 70s. Hi-Res models continue to highlight
the record warmth with the forecast currently sitting on closer to
the 25th percentile of model guidance which is still 3 degrees above
the record of 82 for Indianapolis. While the HRRR often overdoes
temperatures on these warm days, tying the all-time March record of
85 degrees looks to be a reasonable solution and is the current
forecast high.

As for the severe threat, models continue to trend more bullish with
regards to instability thanks to latest warming trends. The CAPE
profile is deep with an EL at nearly 40kft along with a fairly
straight hodograph. The weak cap may not break until the frontal
passage or potentially just after with a good chance that these
storms remain elevated. That would keep hail as the more likely
threat with initiation likely between 7PM and 8PM northwest of
Indianapolis and a gradual southeastern progression through the
remainder of the evening.

&&

.SHORT TERM (Today and tonight)...
Issued at 255 AM EDT Sun Mar 22 2026

Southerly flow continues ahead of a strong cold front approaching
from the north. Temperatures as of 06z are still in the low 60s
across central Indiana despite clear skies and winds under 10kt. The
air mass in place is very warm, originating from anomalously strong
ridging just to our west. Temperatures within the 925-850mb layer
are between 18-24 degrees C. A shallow inversion is noted on IND
ACARS soundings, and it is expected that this will easily mix out
once the sun rises. Assuming efficient adiabatic mixing, surface
temperatures may sore through the 70s and into the low 80s by the
afternoon. Higher resolution guidance that has done well with the
warm temperatures lately even suggests mid to upper 80s from I-70
southward. Temperatures further north are a bit trickier since the
cold front may arrive before diurnal mixing kicks off. Once the
front sweeps through, a quick drop in temperatures through the 60s
and into the 50s is expected.

SEVERE WEATHER POTENTIAL

Another aspect of today`s cold front is the potential for showers
and thunderstorms. In addition to the very warm air, moisture
advection is also ongoing and dew points are expected to rise into
the 50s and low 60s. Height falls aloft point towards steepening
lapse rates and broad synoptic-scale lifting. Guidance is in fairly
good agreement showing between 1500-2000 J/kg MUCAPE developing this
evening with equilibrium levels around 10-12km. Model shear profiles
depict long and curved hodographs corresponding to roughly 60-70kt
of shear. More than enough shear and instability are present for
strong to severe thunderstorms later today.

Shear magnitude suggests supercells are possible while shear vectors
roughly parallel to the cold front suggest a linear mode. As such,
some supercell thunderstorms may develop initially before growing
upscale into a line. Additionally, the front is very strong and
moving quickly south, and likely undercuts developing updrafts. This
may cause most if not all of the storms later today to be elevated.
Model soundings suggest that updrafts will be rooted around the 850-
800mb layer. Since the storms won`t "feel" the shear below 850mb, we
can effectively ignore that part of the hodograph. Taking this into
account, our effective hodograph is long and straight. Combined with
the high EL, this implies that large to very large hail is possible
with the initial elevated supercells. However, once upscale growth
occurs a transition to primarily damaging winds is likely. Tornado
potential is very low, due to the strong cold air undercutting the
storms.

Timing looks to be mainly in the late afternoon and evening, roughly
from 23z to about 04z. Thunderstorms are possible well after the
front moves through, since they are elevated, and rapidly cooling
surface temperatures will not mitigate the hail and wind potential.

MONDAY

Rapid cooling behind the front/storms continues through Monday
morning. Lows may be near freezing, which would be a nearly 50
degree drop in temperature behind the front. Highs on Monday may
rebound to near 50 degrees under partly cloudy skies.

&&

.LONG TERM (Monday through Saturday)...
Issued at 255 AM EDT Sun Mar 22 2026

Anomalous ridging over the western US is modeled to continue through
much of the coming week. Combined with low amplitude troughing over
the northeastern US, the overall flow pattern over Indiana looks to
be northwesterly. This pattern has been in place for a few days now,
and has featured warmer-than-average conditions occasionally
interrupted by fast-moving cold fronts. The cold front expected to
arrive later today will bring temperatures back to near normal to
begin the period.

With a progressive jet pattern overhead, the cool down is not
expected to persist that long and a gradual warming trend begins on
Tuesday. High temperatures rebound into the mid 60s / low 70s by
Wednesday, and then into the mid/upper 70s on Thursday.

The next strong cold front, quite similar to the one we`ll see
today, arrives late Thursday evening. In fact, the set up is nearly
identical to this afternoon. As such, the threat for strong to
severe thunderstorms exists. Some minor details remain in question
though, especially timing and how effectively the front undercuts
developing convection if at all.

A second dramatic cool-down is then shown by Friday with high
temperatures as much as 40 degrees cooler than the previous day.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 706 AM EDT Sun Mar 22 2026

Impacts:

- Wind gusts up to 25-30KT this afternoon and evening
- Winds veering from southwest to north within 14Z-00Z
- Line of TSRA possible after 00Z, mainly impacting IND and BMG
- IFR possible in storms 00Z-04Z...MVFR CIGs after 02Z tonight

Discussion:

VFR conditions will prevail over central Indiana terminals through
at least 00Z this evening...with a transition from record warmth to
seasonably cool conditions by 12Z Monday...including -SHRA and a few
TSRA within 00Z-04Z this evening.  Cold front to pass from north to
south this afternoon, with most rain/TSRA following after.  IFR or
worse is possible in stronger cells this evening, especially at
KBMG.  More widespread MVFR ceilings to arrive from NE to SW around
03Z, although low-VFR is more likely at KHUF...with VFR expected to
return around 12Z Monday.

Southwest flow ahead of the cold front will gust to mainly 23-30KT
after 14Z along/south of I-70.  Front to pass KLAF around 14Z, and
KBMG by 22Z...with northerly flow following the frontal zone
reaching all terminals by 00Z.  Northerly gusts 25-30KT through
04Z...with winds decreasing overnight to around 10KT by 12Z Monday.


&&

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

$$

UPDATE...White
SHORT TERM...Eckhoff
LONG TERM...Eckhoff
AVIATION...AGM