Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 191907

Area Forecast Discussion
National Weather Service Northern Indiana
307 PM EDT TUE JUL 19 2016

Issued at 306 PM EDT Tue Jul 19 2016

High pressure over the Great Lakes will provide fair weather
into tonight. Generally dry conditions should continue Thursday
through Sunday...but there are low chances for thunderstorms as a
hot and humid airmass builds into the area. Lows tonight 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 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 112 PM EDT Tue Jul 19 2016

Scattered VFR cu will persist at or vicinity of taf sites through
at least 22z. KSBN may see cu scour out quicker depending on how
far weak lake breeze can reach inland. Some cirrus blowoff from
convection across Iowa may reach in and dim the skies slightly but
provide no other impacts. cu field may take shape again late Weds
am into the afternoon but will leave out of tafs for now with no
real impacts.


.IWX Watches/Warnings/Advisories...


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

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