Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 200554

Area Forecast Discussion
National Weather Service Northern Indiana
154 AM EDT WED JUL 20 2016

Issued at 128 AM EDT Wed Jul 20 2016

High pressure over the Great Lakes will provide fair weather
overnight. Generally dry conditions should continue this afternoon
through Sunday...but there is a low chance for thunderstorms as a
hot and humid airmass builds into the area. Lows overnight will
drop into the 60s...with highs on Wednesday into the mid to upper
80s. Lows in the 70s and highs in the upper 80s to mid 90s can be
expected Thursday through Sunday.


.SHORT TERM...(This Evening through Wednesday)
Issued at 306 PM EDT Tue Jul 19 2016

Mainly dry/seasonable wx will persist late this afternoon into
tonight as high pressure remains in control. Could see an isolated
shower/sprinkle into far ne IN/MI/nw OH into the mid-late
afternoon along weak boundary where 500 j/kg of MLCAPE available.
However, coverage/chances look too low for a mentionable PoP.

Primary instability/theta-e gradient across the Mid/Upper MS
Valleys will mix slowly east-northeast bringing low chances for
showers/embedded thunder into our western zones (nw IN/sw MI)
later Wednesday morning/afternoon as potential remains for a
weakening upstream convective complex to dive southeast clipping
these areas.


.LONG TERM...(Wednesday Night through Tuesday)
Issued at 306 PM EDT Tue Jul 19 2016

Building heat/humidity and low shower/storm chances becomes the
primary focus Wednesday Night through Sunday as expansive Central
US upper ridge gradually builds into the Ohio Valley and
southwestern Great Lakes. Chances for storms and highs each day
will depend on timing/track of smaller scale convectively aided
waves cresting periphery of ridge into the Upper Midwest and then
diving ese through the Great Lakes. High uncertainty with the low
level focus/convergence more into the northern Great Lakes (and
capping concerns with warm profile) suggest nothing more than
broadbrush 20-30% PoPs the way to go through the period.

Excessive heat/humidity remains the larger concern into IN/sw MI
Thursday and the entire forecast area Friday into this weekend.
Warm overnight lows/sfc dewpoints in the 70s with highs possibly
into the low-mid 90s suggests at least a period of advisory level
heat indices during this time, though confidence remains too low
(cloud debris) at this fcst range for a headline.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 127 AM EDT Wed Jul 20 2016

An upper level ridge will gradually build northeast across the Mid
Mississippi Valley into the Ohio River Valley region. Some energy
will attempt to top the ridge and bring a chance for a storm later
today over northwest Indiana, especially South Bend. Otherwise,
the pressure gradient will remain weak with light winds.


.IWX Watches/Warnings/Advisories...


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

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