IND issues Area Forecast Discussion (AFD) at Mar 28, 9:26 AM EDT371
FXUS63 KIND 281326
AFDIND
Area Forecast Discussion
National Weather Service Indianapolis IN
926 AM EDT Fri Mar 28 2025
.KEY MESSAGES...
- Scattered to numerous showers and a few storms diminishing this
morning
- Frequent wind gusts this afternoon of 30-40 MPH with locally
higher gusts possible
- Much warmer temperatures today into the weekend
- Wet and unsettled pattern developing with periodic rain and storm
chances through Monday
- Strong to severe storms expected Sunday afternoon and evening
&&
.FORECAST UPDATE...
Issued at 926 AM EDT Fri Mar 28 2025
No major changes to the forecast with this update. Trimmed sky cover
a bit as well as PoPs to match current observations. Refined wind
gusts a bit to incorporate latest high-res data...will maintain SPS
for now as even the most robust guidance does not meet advisory
criteria, though it will be close. Wind gusts are the primary
forecast challenge today and observations will need to be monitored
closely.
&&
.SHORT TERM (Today and tonight)...
Issued at 305 AM EDT Fri Mar 28 2025
Early This Morning (Before 8 AM EDT)...
Radar shows scattered to numerous showers developing across Illinois
and northern Indiana, north of a warm front. Isentropic lift was
interacting with elevated instability and increasing moisture, with
area radar VAD wind profiles showing 40-50kt both at 850mb and 925mb.
With isentropic lift and the low level jet continuing during the
early morning hours as the warm front moves north, expect scattered
to numerous convection to continue. Based on radar trends, will keep
highest PoPs across the northern half or so of the forecast area.
Will continue to adjust as needed.
While the strongest storms are expected to remain in Illinois,
enough instability will be across central Indiana for the potential
for some gusty winds and small hail.
Today...
The warm front will continue to push north across the area this
morning. Lift will continue along and north of the front. Based on
radar trends and comparison with model forecasts, the NAM looks too
fast moving the rain north out of the area. Will trend toward slower
solutions and go with likely PoPs north, tapering down to slight
chance PoPs southwest, to start the day.
As the front lifts north, chances for rain will go with it. Will go
dry most areas by 18Z.
Behind the front, clouds will decrease. Mixing will be able to tap
into the strong winds not far off the ground. Wind gusts of 30 to 40
mph will develop this afternoon. Cannot rule out a few higher gusts,
especially west.
Much warmer air will flow in on those gusty southwest winds, with
highs in the middle 70s to around 80 expected.
Tonight...
Central Indiana will remain in the warm sector of the system
tonight. Southwest winds will continue, but gusts will diminish some
as mixing weakens. Still, gusts to 30 mph will occur in some areas,
mainly north.
Much of the night will be dry, but some upper energy will move
southwest to northeast into portions of the forecast area late in
the night. Will have some small PoPs to account for this, mainly in
the southwest forecast area.
The continued southwest winds will keep temperatures well above
normal, with low temperatures only around 60 degrees.
&&
.LONG TERM (Saturday through Thursday)...
Issued at 305 AM EDT Fri Mar 28 2025
A short wave trough is expected to emerge into the Great Plains at
the beginning of the long range. This feature will then induce
cyclogenesis across the Midwest which may lead to increased severe
weather potential as Indiana will firmly be in the system's warm
sector.
The initial short wave will bring scattered to numerous showers and
a few thunderstorms Saturday. The WAA will already be fully settled
in place with highs again in the 70s.
SEVERE WEATHER POTENTIAL AND DETAILS
By Sunday afternoon, guidance generally has surface low pressure
located somewhere near the Illinois and Wisconsin border. There
remains some model differences regarding the evolution and timing of
this feature. These differences have a greater impact on the
mesoscale environment and so confidence is higher for the overall
pattern rather than the small details that could have a big impact
on severe weather potential. Current runs show pre-frontal storms
will be possible through the day although it is still unclear if any
of those will become severe. The front itself and generally more
organized storms along it are expected closer to the evening to
early overnight hours.
With that being said, in all model scenarios Indiana is within the
system's warm sector with a potent south-southwest jet streak
overhead or nearby. Thermal profiles show steep lapse rates and
sufficient instability for thunderstorms. Models show sufficient
shear (over 50kt) for organized convection and potentially strong
thunderstorms. Hodographs are generally long and straight as surface
winds are mainly depicted to be out of the southwest. Based on
current information, wind and hail would be the primary hazards on
Sunday, with a lower threat for tornadoes. Tornadoes are still
possible, as near-surface buoyancy looks to be in place as well as
shear in the 0-1km layer. The tornado threat could increase should
the system evolve in such a way that leads to increased curvature in
the low-level hodographs. Stay tuned for updates as model consensus
increases and these finer-scale details become visible.
Temperatures are again likely to be well-above average as long as
we're in the system's warm sector, before trending downward after
its associated cold front passes through on Monday.
MONDAY ONWARD
A ridge and surface high will bring a couple of days of near normal
temperatures and dry conditions. A progressive synoptic-scale
pattern then looks to continue with another trough modeled to arrive
midweek. Even greater model uncertainty exists regarding this
system, but most guidance shows it to some extent. Confidence is
therefore higher for broad PoPs but that's about it. Yet another
trough is depicted by ensemble guidance arriving next weekend, but
with still lower model agreement we'll just leave it at that.
Overall, an active pattern looks to be upon us with repeated weather
systems passing through.
&&
.AVIATION (12Z TAF Issuance)...
Issued at 633 AM EDT Fri Mar 28 2025
Impacts:
- Scattered showers with isolated thunderstorms this morning
- Non-convective low level wind shear ending early and then possible
again tonight
- Wind gusts over 30kt possible this afternoon.
Discussion:
A warm front will move through the sites this morning. Scattered
showers, and perhaps a thunderstorm, will persist early for the
southern sites and through about 15Z farther north. Cannot rule out
brief MVFR in a shower, but will keep VFR conditions for now. After
the warm front moves north, clouds will scatter out.
Strong winds aloft will create non-convective LLWS early this
morning. Mixing will then bring down some of these winds, with gusts
over 30kt possible afternoon into the evening.
If gusts subside enough tonight, LLWS may return as strong winds
persist aloft.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
UPDATE...Eckhoff
SHORT TERM...50
LONG TERM...KF/Eckhoff
AVIATION...50
Source:
IND issues Area Forecast Discussion (AFD) at Mar 28, 9:26 AM EDT---------------
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