722
fxus63 kiwx 021712
afdiwx
area forecast discussion
national weather service northern indiana
112 pm edt wed sep 2 2026
.key messages...
- heat and humidity continue through thursday with peak heat indices
around 100 degrees, especially along and south of us 30.
- 20-30% chances of thunderstorms thursday, beginning prior to daybreak
mainly north of i-80/i-90 then expanding area-wide by the
afternoon and evening. storms may produce damaging winds. low
confidence at this time.
- 30-60% chances for showers and storms area-wide late thursday
evening into friday morning.
&&
.discussion...
issued at 110 pm edt wed sep 2 2026
heat and humidity persist today with high temperatures expected to
be in the upper 80s to low 90s. the upper level ridge is directly
over the great lakes with a large area of surface high pressure
anchored over the southeastern conus. ample waa will continue to
boost temperatures well above average for early september. increased
moisture return stemming from the gulf will also allow for dewpoints
in the mid 70s to continue. the heat advisory continues for the
entire forecast area until 8 pm edt; it has been extended to last
until 8 pm edt friday for counties along and south of us 30 in
indiana and ohio. confidence is growing that heat indices will
be at or slightly above 100 degrees tomorrow in the vicinity of
the us 30 corridor, where there are lower chances for convection
and/or clouds. we should stay mainly dry today; originally
there was a low chance for a stray storm but given that an
outflow morning from remnant morning upstream convection is
already coming through and there is a downward trend on visible
satellite imagery for cloud cover, have opted to keep the area
dry today and tonight.
as the upper level ridge begins to flatten, our lower michigan
counties may be on the periphery. have maintained 15-20% chances for
isolated convection between 06-18z mainly north of i-80/i-90, with
broader 15-20% expanding into the entire area after 18z thursday
in line with the 12z suite of cams. thursday`s pops are highly
conditional depending on where/if any outflows or shortwaves
setup. depending on how much the ridge flattens and where the
best convective environment sets up, our area may see an active
pattern to end the week into the weekend ahead. hi- res and
medium range guidance suggests one or multiple mcss could move
through the area late thursday night through saturday. model
guidance continues to be all over the place in regards to timing
and exact location of storms thursday through the weekend,
however, in general, our hot and humid environment overhead will
be supportive for convection. we should have ample instability
and moisture to work with but other elements such as shear
remain in question due to considerable uncertainty on how the
larger synoptic evolution.
as mentioned in the previous discussion, there is a large spread on
the long range temperatures and evolution of the upper level ridge.
while the nbm has highs near 80 by late in the weekend into early
next week, there is still about a 10 degree spread in guidance
ranging from 75-85 degrees for highs. with troughing expected to
setup over the western conus, the upper level ridge may briefly
diminish over the weekend and then build back into the area early
into the middle of next week.
&&
.aviation /18z tafs through 18z thursday/...
issued at 105 pm edt wed sep 2 2026
a larger scale upper level trough continues to migrate eastward
this afternoon across eastern ontario/western quebec. another
smaller scale short wave across eastern north dakota will also
take an eastward track well north of the local area. with the
bulk of large scale forcing remaining north of the local area,
questions still remain as to extent of any convection as far
south as northern indiana through this period. another shot of
advective forcing is expected to overspread the southern great
lakes later tonight which could cause some elevated convection
to develop in vicinity of a slowly southward propagating
boundary across lower michigan. given the late timing and more
elevated nature to instability by this time, confidence remains
too low for shower/storm inclusion with the 12z tafs. may also
need to watch remnant outflow boundary across north central
indiana to southern lake huron vicinity for possible isolated
convection this afternoon due to moderate/strong instability.
current thinking is isolated convection along this boundary
would have greatest chances to the east and north of the
terminals. otherwise, vfr conditions expected this period with
low level gradient favoring continued south-southwest winds.
&&
.iwx watches/warnings/advisories...
in...heat advisory until 8 pm edt /7 pm cdt/ this evening for
inz005>009-103-104-203-204.
heat advisory until 8 pm edt /7 pm cdt/ thursday for
inz012>015-017-018-020-022>027-032>034-116-216.
oh...heat advisory until 8 pm edt this evening for ohz001-002-004-
005.
heat advisory until 8 pm edt thursday for ohz015-016-024-025.
mi...heat advisory until 8 pm edt this evening for miz078>081-177-
277.
marine...none.
&&
$$
discussion...johnson
aviation...marsili