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Area forecast discussion 
National Weather Service northern Indiana
144 PM EDT Wednesday Sep 2 2015

issued at 140 PM EDT Wednesday Sep 2 2015

An isolated shower or thunderstorm is possible late this afternoon
and early this evening...but more areas will not receive rain.
There are also small chances for storms during the late afternoons
and the early evenings the next few days as weak upper level
systems combine with daytime heating. Otherwise...very warm and
humid conditions will persist through the rest of the week. Highs
will be in the middle to upper 80s. Lows will be in the middle to upper


Short term...(today and tonight)
issued at 341 am EDT Wednesday Sep 2 2015

Upper level low continues to slowly exit the area this
morning...drifting across southwest Ohio as of 07z. Broad 850-700
hpa warm advection will continue early this morning across much of
lower Michigan/northern Indiana/Northwest Ohio in association with
thickness minimum accompanying departing upper low. Despite this
stronger isentropic upglide overspreading western portions of the
area earlier in the overnight hours...elevated showers have had a
difficult time forming...possibly in part due to fairly strong
dnva with departing upper vorticity maximum. Showers are beginning to fill
in a bit across lower Michigan however...and expecting isolated
showers to continue to develop southward across Northeast
Indiana/Northwest Ohio through the early morning hours as a pocket
of slightly enhanced low level moisture/elevated instability
shifts into Northwest Ohio toward 12z. Strongest isentropic
upglide should eventually focus across southeast third of the area
later this morning/afternoon...and current thinking is best chance
of isolated convection would be across the southeast.
However...with broad isentropic upglide and diurnal
instability...have maintained idea of previous forecast in slight
chance probability of precipitation across approximately eastern half of the area today.
Shear profiles remain very weak today with not much convective
organization expected...with still a possibility of isolated
heavier downpours given small magnitudes to storm motions. Another
unseasonably warm day is in store...even perhaps a few degrees
warmer than yesterday in spots depending on extent of any
convective cloud debris.

Forecast for tonight somewhat muddled given initially weak middle/upper
level forcing across the area and continued broad/weak isentropic
ascent. Hard to discount isolated shower really any time
tonight...but best chance appears to be across the northwest late in
the night as the next upper level short wave approaches from the
northern plains. Have added slight chance thunderstorms and rain probability of precipitation across the
northwest after 09z. Otherwise...another mild night in store with
lows generally in the upper 60s.


Long term...(thursday through tuesday)
issued at 341 am EDT Wednesday Sep 2 2015

Above normal temperatures and mainly dry conditions will remain the
story through Labor Day as an expansive upper ridge builds across
the eastern US/southeast Canada. With that said still several (albeit low)
chances for isolated-scattered precipitation given lack of significant capping
and elevated surface dewpoints supporting modest instability/limited cin
for the afternoon hours each day. Best chances appear to be on
Thursday as a disjointed/weak shortwave drops into the lower lakes
on the northeast periphery of building ridge...although isolated
convection also possible with the heating of the day into Friday-
Saturday as this weakness in the height field and attendant ill-
defined surface trough stall somewhere in the vicinity beneath building

Slightly drier air looks to filter in on either Saturday or
Sunday...with Sunday into Monday morning dry with ridging in command
both aloft and at the surface. A vigorous shortwave lifting out of the
Pacific northwest/northern rockies northeast into south-central Canada will act to
flatten the ridge and send a slowing frontal boundary and renewed
storm chances (and cooler temps) into the local area by Monday night-


Aviation...(for the 18z tafs through 18z Thursday afternoon)
issued at 132 PM EDT Wednesday Sep 2 2015

There is an outside chance for a shower or storm at the
terminals...but felt the chances were too low given weak
subisdence and stable lapse rates in the middle kept tafs


Iwx watches/warnings/advisories...


short term...marsili
long term...steinwedel

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