600
FXUS63 KIND 090649
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
249 AM EDT Mon Mar 9 2026

.KEY MESSAGES...

- Widespread minor/moderate river flooding continues south of I-70

- Locally heavy rainfall is expected late Tuesday into Wednesday,
  which will exacerbate or prolong ongoing flooding

- Scattered severe storms with all hazards are possible Tuesday
  night and Wednesday

- Well above normal temperatures expected through Wednesday

- Cooler temperatures for late this week

&&

.SHORT TERM (Today through Wednesday)...
Issued at 249 AM EDT Mon Mar 9 2026

Clear skies across the Ohio Valley early this morning with a high
pressure ridge centered to our southeast. S/SW winds around 10mph
were keeping temperatures up with mid and upper 40s across much of
the forecast area at 06Z.

The surface ridge will maintain its influence over the Ohio Valley
today in particular...but a developing frontal boundary extending
from the High Plains to the Great Lakes will increasingly become a
focal point for convective development by late Tuesday as a surface
wave kicks east into the mid Mississippi Valley. Severe storms and
heavy rainfall will impact the forecast area Tuesday night and
Wednesday as the cold front slowly sags across the forecast area.

Through Early Tuesday

Low pressure will track across the northern Great Lakes this morning
and into western Quebec later today. As it does the pressure
gradient will tighten with the surface ridge centered over the lower
Appalachians resulting in breezy conditions across central Indiana
for this afternoon. Peak gusts will be around 25mph before dropping
off with the development of an inversion this evening.

Sunshine will be plentiful across the region for much of the day but
the onset of warm advection in tandem with a plume of moisture
lifting into the lower Oho Valley will support a gradual expansion
of stratus into the forecast area from the southwest late today into
this evening. The development of a boundary layer inversion will
effectively trap moisture beneath it with stratus becoming
widespread tonight. Model soundings support the potential for
pockets of drizzle tonight with a broad area of dry air and
subsidence present above the inversion.

Tuesday through Wednesday

A frontal boundary shifting south will align across the lower Great
Lakes by Tuesday afternoon with a progressively moist airmass south
of the boundary across the Ohio Valley as dewpoints surge into the
60s. Showers may develop in the vicinity of the boundary but
conditions will remain benign for much of the day as a capping
inversion develops over much of the region south of the boundary.
The approach of a stronger surface wave in tandem with an increase
in 850mb flow will help to unlock the convective development near
the boundary late Tuesday with the potential for explosive
organization with a supercell mode across northeast Missouri into
the northern half of Illinois as the cap breaks in a highly sheared
and modestly unstable environment with steep mid level lapse rates.

The cap will hold into Tuesday evening before weakening further
south across central Indiana with the primary focus for severe
convection remaining to the northwest of the forecast area. Storms
Tuesday evening will carry a tornado risk with impressive 0-1km SRH
values and hodographs showing strong curvature in the lowest 2-3km.
Plenty of instability within the hail growth zone also supports the
potential for large hail. Not out of the question that the
supercells that develop may end up clipping the northern Wabash
Valley by mid to late evening as the front shifts south but for the
most part...any convective impacts will be minimal across the
forecast area through the evening.

Convection will gradually grown upscale into clusters or lines as
storms shift southeast into the forecast area Tuesday night. Model
soundings continue to advertise ample directional shear and SRH
within the boundary layer that supports a continued risk for
rotating storms and tornadoes...but damaging winds are likely to
become an increasing threat Tuesday night into Wednesday morning as
convective mode becomes more chaotic and storms tap into 50+kt winds
in the lowest 2-3km. After a brief lull...additional convective
development along the eastward moving cold front is expected
Wednesday afternoon focused across the southeast half of the
forecast area. With weaker instability and less directional shear
present...convection will primarily carry a risk for damaging winds
before shifting east of the forecast area by early Wednesday evening.

While the severe weather threat is valid even with the timeframe of
greatest impacts expected overnight Tuesday into Wednesday
morning...the flooding concern is greater as confidence continues to
grow in heavy rainfall impacting much of the forecast area.
Precipitable water values will peak late Tuesday night and Wednesday
morning in excess of 1.50 inches which is about 300% of the
climatological normal. A broad 1 to 2 inches of rain is anticipated
with pockets of higher amounts expected. This will exacerbate and
potentially worsen ongoing river flooding while offering the risk
for localized flash flooding due to high rainfall rates.

Temps...low level thermals support highs near 70 this afternoon. The
record high at Indianapolis today is 72 from 1878 and it will be
close. The potential to break a record high will come Tuesday as mid
70s abound across the forecast area. The record high for Tuesday at
Indy is 74 from 2009 and the current forecast is for a high of 75.
Temperatures will remain well above normal Wednesday but expect
temps to begin falling in the afternoon as the front passes. Lows
tonight and Tuesday night will surge into the 60s over much of the
area.

&&

.LONG TERM (Wednesday Night through Sunday)...
Issued at 249 AM EDT Mon Mar 9 2026

The upper level pattern across the country will transition to more
of a northwest flow orientation in the wake of the midweek system
with a flat ridge off the California coast. Fast moving storm
systems will track through the progressive flow aloft and largely
remain north of the region into the first part of the weekend.
Deepening upper level energy diving out of western Canada will help
to strengthen low pressure over the central Plains Sunday. The low
with a trailing cold front will sweep across the region late Sunday
bringing another opportunity for rainfall to wrap up the weekend.
Behind this system...colder air will spread into the region for
early next week as the upper level pattern becomes increasingly
amplified with a ridge west and a trough east.

Lingering rain showers across southeast parts of the area will
depart Wednesday evening with clearing into early Thursday as deep
subsidence overspreads the Ohio Valley with a broad area of high
pressure. This will bring dry and seasonable weather to the region
for Thursday with warmer temperatures Friday as low level flow
swings back around to southerly. A fast moving surface wave will
track across the Great Lakes early Friday and may bring a few light
showers to the northern half of the forecast area...otherwise dry
conditions will reign into the first part of the weekend.

A warm front will extend into the region by late Saturday as low
pressure begins to organize over the central Rockies. Precipitation
should remain to the north of the boundary as it aligns across the
lower Great Lakes. The ejection of the surface low out into the
Plains then E/NE into the Great Lakes by late Sunday will bring a
convective threat as the attendant cold front sweeps across the
region Sunday evening. The fast moving nature of the boundary should
limit heavier rainfall amounts. In the wake of this system...colder
air will filter into the area with an amplified upper level ridge
west-trough east developing for the first half of next week. Highs
in the 60s Sunday will be followed by highs 20 to 25 degrees colder
next Monday through Wednesday.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 1228 AM EDT Mon Mar 9 2026

Impacts:

- Gusts to 20-25kt this afternoon
- MVFR ceilings arriving from the southwest late today

Discussion:

VFR conditions will continue through late today.

Southwest winds will persist through much of the day...increasing
this afternoon as the pressure gradient gradually tightens. Peak
gusts at 20 to 25kts are possible this afternoon before dropping
back to 10 to 15kts this evening.

Mainly clear skies are expected through late afternoon but lower
stratus will advect into the region from the southwest late today
with MVFR ceilings encompassing the terminals into this evening.


&&

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

$$

SHORT TERM...Ryan
LONG TERM...Ryan
AVIATION...Ryan