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Area forecast discussion
National Weather Service northern Indiana
652 PM EDT Fri Jun 23 2017

issued at 237 PM EDT Fri Jun 23 2017

Cooler and less humid air will settle across the region tonight.
Showers will continue to move out of the area leading to a mostly
cloudy evening. After a clear start to the day Saturday, clouds
will increase during the afternoon, but rainfall will hold off
until Sunday afternoon. Low temperatures tonight will be in the
upper 50s with highs Saturday in the lower to middle 70s. Cooler
and drier weather will persist into the early part of next week.


Short term...(this evening through saturday)
issued at 237 PM EDT Fri Jun 23 2017

West-northwest flow will persist through Saturday, ushering in
cooler and less humid air. Boundary layer will be well mixed do
not expect to see any fog formation by morning.

Afternoon heating will lead to formation of cu...especially Lee
of Lake Michigan. Lack of deep moisture and instability will keep
the threat of measurable precipitation to nearly nil. As the
clouds increase during the peak heating Saturday, this will keep
temperatures from climbing too rapidly and have kept with the
previous trend of low-mid 70s for highs.


Long term...(saturday night through friday)
issued at 237 PM EDT Fri Jun 23 2017

The trof over the Great Lakes will deepen and amplify slightly in
response to the ridging over The Rockies. This amplification will
result in continued influx of cooler air. With this amplification
the models are hinting at short waves embedded in the flow.
Similar to past several events of troffing over the Great Lakes
will see the clouds increase and there will be isold/scattered
light showers late Sunday with the threat continuing through
Monday. This is not a heavy rain event and do not expect to see
deep convection either.

The next threat of significant convection will be as the ridging
shifts eastward. Temperatures and moisture will increase...leading
to increased instability and greater threat for thunderstorm late
weednesday into Friday. At this time there is low confidence in
talking about timing and intensity. This will need to be watched
and monitored as we get closer to the event. A head's up for
planning for events that may be planned late in the week as we
approach the 4th of July weekend.


Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 649 PM EDT Fri Jun 23 2017

Drier air will cont to filter into nrn in tonight via W-NW flow behind
departing cdfnt providing contd VFR conditions. Prbly sufficient
lingering low level moisture combined with rather cool temps aloft
to cause VFR bkn cu cloud deck to form by late Sat morning and
cont through the aftn. Isolated shra not out of the question, but
threat too low to include in tafs. West-northwest winds should gust into the
20-25kt range during peak heating/mixing Saturday aftn.


Iwx watches/warnings/advisories...


short term...Lewis
long term...Lewis

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