031
fxus63 kiwx 121034
afdiwx
area forecast discussion
national weather service northern indiana
634 am edt sun apr 12 2026
.key messages...
* today will mark the beginning of an extended period of much
above normal temperatures. highs today will range from 75 to
80.
* windy today with peak afternoon gusts as high as 35 to 40 mph
at times.
* an active period of showers and thunderstorm chances through
the middle of the week. greatest probability of showers and
storms is tuesday night and wednesday (60-80%). there is a
potential of severe weather, mainly late tuesday afternoon and
night along with wednesday afternoon and early evening.
&&
.discussion...
issued at 324 am edt sun apr 12 2026
scattered showers have developed across lower michigan this morning
in response to a retreating low level warm frontal boundary.
stronger moisture transport is displaced well to the west of the
local area this morning however, along an axis from central
oklahoma to central iowa. the strongest isentropic upglide this
morning should continue through around 12z, with focus for
additional showers likely shifting north of the area after this
time. the overall forecast scenario has not changed much for
today with the entire area quickly become entrenched in broad
warm sector.
near term forecast soundings suggest deep mixing profiles today
which should allow from 35 knot boundary layer winds to mix to the
sfc. given recent guidance trends and collaboration with surrounding
offices, did slightly nudge up wind gusts today to around 35
mph, although a few higher gusts are possible particularly from
northwest indiana to southwest lower michigan where href
guidance depicts 30- 40% probs of wind gusts over 40 mph. this
deep mixing and stronger warm advection from this morning should
allows highs to reach into the 75 to 80 degree range most
locations.
the relatively non-impressive low level moisture transport
trajectories from the lower ms valley continue today, so afternoon
instability should be limited to a just a few hundred j/kg of
surface-based cape from nw in/sw lower mi this afternoon. stronger
forcing this afternoon should continue to be displaced west of the
area, at least until tonight when a stronger mid level short wave
ejects northeast across the western great lakes. northward
progression of this feature should eventually allow an axis of
better low level moisture across the mid ms rvr valley to
shift across the local area. no significant change made to previous
forecast grids with likely rain shower pops (60-80%) and slight
chance thunder pops tonight.
focus for monday through wednesday will turn to evolution of western
conus split flow pattern and its contribution to increase
shower/storm chances mon-wed. on monday, guidance has been
consistent in depicting a piece of southern stream upper trough
getting ingested into a more progressive northern stream trough
working across the northern plains/upper midwest by monday
night. with better advective/dynamic forcing northwest of local
area on monday, confidence is still relatively low on
thunderstorm coverage for monday afternoon/evening. did maintain
some low chance pops during the day monday with perhaps some
synoptic contribution in right entrance region of great lakes
jet streak south of the warm front. an item contributing to low
confidence in some steeper mid level lapse rates advecting into
the region monday which could act to cap convective development.
perhaps best chance of storms monday would be during the
nighttime when potential composite outflow could drop across
southern great lakes into early tuesday, or potential southward
propagation in upwind sense via low level jet feeding into the
southern great lakes.
greater chance of thunder still appears to be intact for tuesday and
wednesday, although expected uncertainties remain. overnight
monday/early tuesday convection across great lakes could have some
influence on composite boundary positioning which would be important
for favored initiation areas in the afternoon/evening. a
scenario could evolve where weak sfc based cin persists through
much of tuesday. tuesday evening could feature best convective
potential with synoptic setup more favorable by this time for a
mid level speed max to eject across the southern great lakes
downstream of the more pronounced upper wave across the central
rockies. if storms can develop, this would be a decently sheared
environment and combination of this shear and good level mid
level lapse rates aloft would conditionally make all severe
hazards possible for a time including some locally heavy rain
potential.
wednesday convective potential is even less clear at this time, but
will be in place given the slow evolution of the shearing rockies
short wave as it ejects northeast across the northern great lakes
into early thursday. convective debris from potential overnight
storms tuesday and likely weakening mid level lapse rates by this
time could limit instability magnitudes, but at least an
isolated strong/severe risk could evolve wed afternoon/evening.
dampening nature of this upper wave on thursday will result in no
break from the much above normal temperatures into friday as another
longwave trough digs across western conus friday. deterministic and
ensemble solutions are exhibiting quite a spread in the progression
of this wave and associated cold frontal boundary for next
weekend with ensemble means generally more progressive than
their deterministic counterpart. initial feeling is that the
slower idea may have some validity given nature of large scale
synoptic flow in being stubborn to break down the eastern conus
ridge resulting in slower, highly sheared nature of upper level
waves. depending on timing, this could yield another period of
convective potential early next weekend with the associated cold
front. a trend to cooler temperatures still looks likely
heading into early next week behind this cold front.
&&
.aviation /12z tafs through 12z monday/...
issued at 630 am edt sun apr 12 2026
the stronger isentropic lift early this morning is lifting north
of northern indiana, with additional isolated showers likely to
affect areas north of the terminals. a warm front will quickly
shift north of the area this morning. despite strengthening
southerly flow in warm sector, moisture transport is not all
that impressive with primary low level moisture axis nosing into
the corn belt. without clear additional forcing mechanisms today
and better instability remaining west of the area, will keep
tafs dry through the day. a mid level trough lifting out of the
southern plains will allow this upstream moisture axis to shift
across the ohio valley and southern great lakes tonight bringing
a period of showers with perhaps an isolated storm.
deep mixing today in warm sector should promote south to
southwest gusts to 30 to 35 knots at times and eastward
translation of low level jet axis should keep some healthy gusts
going through the night tonight. will maintain a brief period
of llws to begin this forecast valid period at ksbn, with
marginal llws possibly being met again later tonight. will let
later shifts assess this potential.
&&
.iwx watches/warnings/advisories...
in...none.
oh...none.
mi...none.
marine...small craft advisory until 8 am edt monday for lmz043-046.
&&
$$
discussion...marsili
aviation...marsili