Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 201936

Area Forecast Discussion
National Weather Service Northern Indiana
336 PM EDT SAT AUG 20 2016

Issued at 333 PM EDT Sat Aug 20 2016

A cold front will move through the region this evening. Scattered
showers and thunderstorms can be expected along and ahead of this
front. Cooler and less humid air will arrive later tonight and
linger into the start of the new work week. Lows tonight will be
in the 60s while highs on Sunday will only be in the lower to
middle 70s.


.SHORT TERM...(This Evening through Sunday)
Issued at 333 PM EDT Sat Aug 20 2016

Broken line of convection along pre-frontal trough will continue
to work east through the forecast area into early evening. Modest
shear of 20-30 knots with veering wind profile has led to some
weak rotation in storms. However...instability remains weak in the
500- 1000 j/kg range with some pockets around 1500 j/kg. With this
limited instability...updrafts have struggled to reach sufficient
height for a lot of lightning. Tops have been around 25-30kft and
this is around height of -20C level. The combination of modest
shear and limited CAPE will still be enough for a few stronger
storms with some rotation into the early evening. Isolated strong
storms remain possible. Cannot rule out a funnel cloud or even
isolated tornado given the circulations we saw earlier this
afternoon leave our Michigan counties. However...believe those
were enhanced by mesoscale effects of lakeshore and frictional
components as line of storms moved off Lake Michigan coupled with
stronger shear profiles to our north.

Main front to cross the area this evening and early
tonight...bringing and end to rain chances. Models have remained
consistent with secondary and tertiary short waves driving through
mean trough Sunday with wrap around moisture clipping our far north.
Did add a low chance PoP for these features. Models also showing 500-
1000 j/kg CAPE with residual moisture and cold air advection aloft
with steepening low level lapse rates. Included mention of thunder
though expect coverage to be mainly isolated. It will be a bit
breezy...cooler and less humid. Highs only expected in the 70s and
lower Michigan sites may stay in the upper 60s if clouds and showers
do develop.


.LONG TERM...(Sunday Night through Saturday)
Issued at 333 PM EDT Sat Aug 20 2016

Once again with active weather in the near term have generally
followed Superblend init. Did limit PoPs once again to less than 60
percent given uncertainty at longer lead times with convection and
timing of systems. Otherwise it looks cool and dry Sunday and Monday
with warming trend Tuesday into Wednesday. Next system will
approach with chances for showers and storms Wednesday and Thursday.
Kept Friday and Saturday dry for now with front moving south of area
and high pressure building back in per GFS and ECMWF 12z solutions.


.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 112 PM EDT Sat Aug 20 2016

Theta-e surge along pre-frontal trough will provide several rounds
of showers/embedded thunder through mid afternoon...with
additional rain/storms expected late afternoon along a cold front.
CIGs mainly in the MVFR to low end VFR range expected, though a
period of IFR conditions possible with more organized line of
rain/thunder into KSBN early afternoon and KFWA mid afternoon.
Winds will likely gust 20-30 knots at times. VFR/dry otherwise
tonight-Sunday post-frontal as extensive low VFR stratocu works


.IWX Watches/Warnings/Advisories...
IN...Beach Hazards Statement through Sunday evening for INZ003.

MI...Beach Hazards Statement through late Sunday night for MIZ077.

LM...Small Craft Advisory until 1 AM EDT Monday for LMZ043-046.



SHORT TERM...Lashley
LONG TERM...Lashley

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