Indiana’s Weather For Today

HEADLINES
– Another great day!
– Fast-moving severe storms with damaging winds late Friday night into early Saturday.
– Strong winds Friday through Saturday outside of storms. Up to 35 mph Friday, 45 mph Saturday.
– Rain totals of 1-2 inches may produce localized flash and lowland river flooding.

SEVERE OUTLOOK (8am Friday-8am Saturday)
BIGGEST THREAT IS OVERNIGHT AND PRE-SUNRISE SATURDAY

SEVERE OUTLOOK (8am Saturday-8am Sunday)
BIGGEST THREAT IS AFTER 5PM INTO EVENING

TODAY’S MAP

NWS TECHNICAL DISCUSSION

Another pleasant and warm day and mostly clear night is expected
across Central Indiana with above normal temperatures. Models show
the upper ridging and the upper low moving east. These two elements
will help pull the surface warm front north to Central Indiana
today. Again, this front remains moisture starved as forecast
soundings remain dry through the day and mid levels show subsidence.
The upper low passing across the deep south may allow for a bit more
cloud cover across southern parts of the forecast area, but overall
mostly sunny to partly cloudy skies will work well. 850Mb temps
remain changed little today as compared to yesterday. Thus we expect
similar high temperatures, near persistence, with lower 70s north to
the mid 70s south.

Tonight -

Models tonight push the upper low out to the Atlantic while ridging
builds aloft over the Ohio Valley and Great Lakes. Meanwhile, our
next system for Friday night will be pushing across the 4 corners
area in the American SW. The ridging aloft over Indiana will lead to
another quiet and warm night across Central Indiana as forcing is
not available. Deepening strong surface low pressure over the plains
states will also help to push the warm farther north on
southeasterly winds also resulting in an increasing surface pressure
gradient. Again forecast soundings show a dry column with a lower
level inversion in place. All of this will add up to mostly clear
skies and a mild night with lows in the upper 40s and lower 50s.

&&

.LONG TERM (Friday through Wednesday)...
Issued at 331 AM EDT Thu Mar 13 2025

- THREAT FOR SEVERE THUNDERSTORMS FRIDAY NIGHT INTO EARLY SATURDAY

- THREAT FOR STRONG GRADIENT WIND GUSTS FRIDAY NIGHT INTO SATURDAY
  AFTERNOON

Friday through Saturday Night -

SEVERE THREAT

The most significant concern during the long term is the severe
threat late Friday night into early Saturday morning. At this time,
the highest threat for severe storms appears to be in the midnight
to 6 AM time frame across central Indiana.

Low level and deep layer shear will not be in question whatsoever,
with off-the-charts progs for both. As is frequently the case this
time of year, instability may be the primary limiting factor,
particularly given the diurnal timing - though with strongly forced
convective systems w/ ongoing theta e advection, these limiting
factors can be sometimes be overcome with ease. Additionally,
guidance tends to struggle with eastward persistence of overnight
convection, particularly in this part of the country.

The most likely scenario at this time is explosive thunderstorm
development to our west/southwest Friday afternoon, quickly
coalescing into a severe QLCS and racing northeastward toward the
area during the evening and crossing the region late Friday night.
While some weakening should occur as it does so, the system may
arrive on our doorstep extremely strong, and capable of widespread
damaging winds (perhaps some significant swaths) and a few
tornadoes. Storm motions of perhaps 60-70 MPH will be possible if
not likely.

The uncertainties are with respect to the exact timing of the system
(earlier arrival would likely mean greater strength and eastward
persistence) and location of the most intense portion of the system -
but nonetheless, a threat for dangerous overnight severe storms will
exist for central Indiana late Friday night.

HYDROLOGIC CONCERN

Heavy rain will certainly be a threat given precipitable water
values expected to be near climatological maximum for the time of
year, but the aforementioned rapid storm motion will limit this
concern with the first round.

A lull in precipitation appears likely Saturday morning, with
secondary cyclogenesis to our southwest over the mid Mississippi
valley during the day on Saturday ahead of another upper level wave
in the larger upper trough. Guidance trends in recent days have
pulled this a bit further west, posing at least some threat for
additional thunderstorms and heavy rain/flooding in the lower Ohio
Valley Saturday afternoon into Saturday evening. At this time, the
most significant portion of this threat looks to be concentrated
further to our south, but southeastern portions of central Indiana
are not entirely out of the woods here, either, and the hydrologic
situation will merit monitoring in the wake of round one, and as
round two develops Saturday.

Total rainfall amounts ranging from near an inch to over 2 inches
from Friday night into Saturday night appear likely at this time,
with the highest amounts southeast, and hydrologic ensembles do show
at least chances for widespread bankfull conditions and a few areas
of lowland flooding in southern and southwest central Indiana, in
addition to the localized flash flood threat, which is handled well
by day 3/4 marginal excessive rainfall risks from WPC.

GRADIENT WIND THREAT

As for gradient winds, plentiful deep mixing in the boundary layer
on a very warm Friday will promote easy momentum transfer from
fairly strong flow not far off the surface owing to the potency of
the intense mid-latitude cyclone moving out of the central Plains
toward the upper Midwest. Sustained southerly winds of 15-25 MPH
with frequent gusts of 30-40 MPH at times, particularly in the
afternoon when mixing is at its deepest, are likely, with isolated
higher gusts.

Friday night into Saturday, low to midlevel flow will continue to
intensify, with a low level jet as strong as 60-70KT overspreading
the area overnight, decreasing a bit to 45-50KT Saturday. 50KT flow
is possible within 1000-1500 feet AGL per GFS soundings, which not
only contributes to the significant concern for damaging winds, but
also the gradient wind threat as well.

Though diurnal influences would generally tend to temper momentum
transfer overnight, the intensity of the flow and continued warm
advection will likely severely hamper any tendency for deeper near
surface stabilization, and gusts outside of thunderstorms will
likely continue. Sustained winds of 20-25 MPH with frequent gusts of
35-45 MPH are likely.

As we move into Saturday, particularly through the early afternoon
hours before low level flow weakens significantly, sustained winds
will likely be 20-30 MPH with frequent gusts of 40-50 MPH.

Locally higher gusts will be possible throughout this time frame,
and isolated gradient wind gusts of 55-60 MPH cannot be entirely
ruled out, mainly Friday night into early Saturday.

Sunday Onward -

The last lingering showers should be clearing out of the area early
Sunday, with dry weather expected through at least Tuesday night as
upper level ridging downstream of another potent upper level trough
builds over the region. A brief cooldown late in the weekend will
quickly see temperatures return to well above normal early to mid
work week.

INDY SEVEN DAY FORECAST

Paul Poteet <paul@paulpoteet.com> 1:25 AM (7 hours ago)
to Post

#: Indianapolis Forecast#
Today: Mostly sunny. High 75.

Tonight: Mostly clear. Low 52.

Friday: Mostly sunny. Wind gusting to 30 mph. High 76.

Friday Night: Showers and storms after midnight. Severe storms, heavy rain and high wind possible. Low 60.

Saturday: Showers and storms, mainly in the early morning. Becoming partly sunny. Wind gusting to 45 mph! High 73.

Saturday Night: Showers and storms. Low 42.

Sunday: Early morning shower chance, then mostly cloudy and cooler. Partly sunny by later afternoon. High 48.

Sunday Night: Partly cloudy. Low 31.

Monday: Sunny. High 58.

Monday Night: Mostly clear. Low 45.

Tuesday: Mostly sunny. High 69.

Tuesday Night: Partly cloudy. Low 52.

Wednesday: Mostly cloudy. Scattered showers and storms by afternoon. High 69.

NWS CHARTS FOR TODAY/TONIGHT