Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 181813 CCA

Area Forecast Discussion...Correction
National Weather Service Northern Indiana
212 PM EDT Fri Aug 18 2017

Issued at 210 PM EDT Fri Aug 18 2017

Dry and partly cloudy conditions this afternoon and evening will
be followed by chances for scattered showers and isolated
thunderstorms later tonight into Saturday morning. Lows tonight
will drop into the 60s, with highs on Saturday near 80 degrees.
High pressure then builds in later Saturday through Monday with
dry conditions and seasonable temperatures. Monday night through
Tuesday evening will feature the next chances for showers and
thunderstorms as a cold front moves through the region.


.SHORT TERM...(This Evening through Saturday)
Issued at 210 PM EDT Fri Aug 18 2017

A shortwave over the Upper Midwest will sharpen southeast into
leftover longwave troughing over the Great Lakes region later
tonight into early Saturday. Backing low-mid level flow with this
seasonably strong wave will tighten the downstream moisture/thermal
gradient over nrn IN/nw OH with a 3-6 hour window for
chances 5-11z across nrn IN/Lower MI and nw OH 8-14z. Elevated
instability into the developing frontal slope may support a few
thunderstorms and brief heavy downpours. The overall moisture
quality does appear to be somewhat lacking with this system
despite good deep layer dynamics. This may keep precipitation more

Subsident northwest flow in wake of the upper wave will allow for
quick drying and clearing from west to east by later Saturday
morning and afternoon. This clearing should allow afternoon highs to
recover to near 80F.


.LONG TERM...(Saturday Night through Friday)
Issued at 210 PM EDT Fri Aug 18 2017

The synoptic pattern will briefly transition to a more zonal flow
configuration Sunday into Monday. This will promote mainly dry and
warmer conditions with weak low level ridging dominating during this

Upper level longwave trough amplification into the Eastern US mid-
late week then brings a strong cold through around Tuesday/Tuesday
night, followed by cooler/dry wx Wednesday through Friday. A
couple rounds of showers/storms may accompany the frontal passage
Monday night through Tuesday night with severe weather not out of
the question Tuesday aftn/eve given ample pre-frontal moisture
return under increasing wsw flow aloft.


.AVIATION...(For the 18Z TAFS through 18Z Saturday)
Issued at 208 PM EDT Fri Aug 18 2017

Brief mvfr cig restriction early this aftn but boundary layer will
continue to deepen/mix as upper trough over srn ON lifts out.
Otherwise attention turns toward incoming upstream sw trough
wrapping through ern MN. Fairly vigorous low level mass flux ahead
of this feature with substantial low level theta-e ridge inflection
seen into nrn IN after midnight with vcts mention added invof KSBN
and likely needed invof KFWA although cams based timing there more


IN...Beach Hazards Statement until 4 PM CDT this afternoon for

MI...Beach Hazards Statement until 5 PM EDT this afternoon for

LM...Small Craft Advisory until 5 PM EDT this afternoon for LMZ043-



SHORT TERM...Steinwedel
LONG TERM...Steinwedel

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