Indiana’s Weather For Friday

SNOW TOTALS
FOR MOST: 2-4 inches
LAFAYETTE AREA: 1-3 inches
NEAR AND SOUTH OF I-70: 2-5 inches

Via @NWSIndianapolis… Light to moderate snow has arrived in western Indiana, moving east/northeast this morning. Expect it to reach the Indianapolis metro between 11AM-12PM, with eastern central Indiana impacted shortly after.

TODAY’S MAP

WEATHER SERVICE INDIANAPOLIS TECHNICAL DISCUSSION

The primary surface low will remain confined to a track along the
Gulf Coast through tonight...but its interaction with a deep
meridional upper level trough and a frontal boundary extending north
into the Great Lakes. Moisture will advect poleward ahead of the
front and encompass the Ohio Valley later this morning.

Initially...a broad layer of dry air generally below 650mb will
slowly saturate from the top down but in the absence of more
substantial lift...this process will take some time with snow
holding off on expanding into the Wabash Valley until near daybreak
at the earliest and even then...it may take until late morning for
snow to become steadier and more widespread over the forecast area
as persistent southeasterly flow through the near surface layer
delays more substantial saturation.

The heaviest snow rates will come this afternoon into the early
evening as the deepest moisture aligns with an axis of stronger
isentropic lift north of a low level jet pivoting through the
Tennessee Valley. The favorable left front exit region of a strong
upper level jet will track through the Ohio Valley and further aid
in the broad area of snowfall through the afternoon. Deep moisture
and lift will extend up through the dendritic growth zone for
several hours as well and may enable brief periods of slightly
heavier snowfall rates. A dry slot will expand northeast from the
lower Mississippi Valley will expand northeast as far as Kentucky by
late day...but the presence of enhanced forcing ahead of the
approaching surface front and upper trough will maintain light to
moderate snowfall into the evening across the region.

While snow rates will gradually lighten and coverage will decrease
through the evening as the deeper isentropic lift shifts to the east
of central Indiana...anticipate snow will not completely diminish
until the trailing upper trough axis moves through the forecast area
around or shortly after midnight. Low clouds will persist through
daybreak Saturday as model soundings show low level moisture trapped
beneath an inversion for the remainder of the night.

Snowfall and Headlines:

High confidence continues in overall precipitation amounts for much
of the forecast area from 0.15 in the northern Wabash Valley to
around 0.25 inches over the southern half of the forecast area. The
cold surface temps and overall thermal profiles remain supportive of
snowfall ratios hovering near 15:1 for much of the upcoming event
resulting in overall snowfall totals of 3 to 4 inches for much of
the forecast area...with slightly lower amounts over the far
northwest counties of the forecast area. There remains potential
for a few spots to overachieve locally higher than 4 inches...most
likely across the southeast half of central Indiana where the
highest qpf values will reside.

The Winter Weather Advisory will continue but with subtle changes to
start and end times based on overall trends. Will push back the
start time this morning to 12Z based on the slower onset...and bring
the end time to the headline tonight up by a few hours to 06Z Sat.

.LONG TERM (Saturday through Thursday)...
Issued at 258 AM EST Fri Jan 10 2025

The long term period will be characterized by fluctuating but still
primarily below normal temperatures, with multiple upper
level waves moving through the larger scale cyclonic flow in place
across much of the country.

One or more low probability chances for precipitation will be
possible, but with significant questions about both moisture
availability and model disagreement, the only mentioned PoPs during
the long term will come Sunday afternoon and evening.

Forecast profiles show very disjointed moisture with this late
weekend disturbance, with upper levels saturating Saturday night but
drying out by the time low levels moisten up and forcing arrives.
Will carry a mention of snow showers or freezing drizzle during this
period, given the modeled loss of cloud ice. Will need to keep an
eye on this as the weekend goes along.

Another fairly substantial cold blast is expected in the wake of
this late weekend system, with temperatures likely to fall much of
the day Monday. Several single digit nights are likely again this
week, with subzero temperatures again possible as well.

Temperatures may moderate a bit late in the week into the coming
weekend, but models suggest this will be brief, with another,
potentially even more significant Arctic airmass poised to plunge
into the CONUS at the beginning of the following week.

INDY SEVEN DAY FORECAST
Today: Snow begins in the late morning, and continues all afternoon. High 27.

Tonight: Snow fades by late evening. 3-5 inches total. Low 20.

Saturday: Mostly cloudy. High 28.

Saturday Night: Partly to mostly cloudy. Low 19.

Sunday: Partly to mostly cloudy. High 33.

Sunday Night: Mostly cloudy, with a few flurries and snow showers in the late evening and overnight. Low 22.

Monday: Mostly cloudy morning. Partly sunny later. A few flurries possible. High 27.

Monday Night: Partly cloudy. Low 8.

Tuesday: Partly sunny. High 16.

Tuesday Night: Partly cloudy. Low 4.

Wednesday: Partly sunny. High 20.

Wednesday: Partly cloudy. Low 9.

Thursday: Partly sunny. High 31.

NWS CHARTS FOR TODAY/TONIGHT