Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 200535

Area Forecast Discussion
National Weather Service Northern Indiana
135 AM EDT Wed Sep 20 2017

Issued at 730 PM EDT Tue Sep 19 2017

Skies will slowly clear overnight and areas of dense fog are
expected to develop, especially over northern Indiana and lower
Michigan. Visibilities could be near zero in some locations
toward daybreak. Low temperatures will be in the lower to middle
60s. The fog will dissipate through the morning with mostly sunny
skies in the afternoon. High temperatures will rise into the 80s.
Very warm and dry conditions will continue into the weekend with
highs in the middle to upper 80s and even some lower 90s possible.


.SHORT TERM...(Tonight and Wednesday)
Issued at 253 PM EDT Tue Sep 19 2017

Pesky upper low over wrn Starke county has moved little through this
morning and will only slowly weaken newd into srn MI by this
evening. Trailing sfc trough and some weak sfc based instability
will yield greatest coverage of shra/thunder rumble this aftn
along/east of I69.

Otherwise upstream look across IL suggests partial clearing will
develop esp wrn half overnight and given widespread significant
rainfall early this morning and no appreciable advective change in
airmass expect dense fog will likely result late tonight. Will keep
close to prior gridded mention.

Subsidence behind departing trough and increasing swrly flow by late
morning will scour any remain fog/low clouds. Given insolation and
beginning of upper ridge amplification by aftn expect quite warm
temps... marking what looks to be a very warm long term period.


.LONG TERM...(Thursday through Tuesday)
Issued at 253 PM EDT Tue Sep 19 2017

This period will be characterized by unseasonable warm and dryness
as blocking ridge expands across the Great Lakes upstream of wrn
Atlantic tag team of Hurricanes Jose and Maria. In fact upper ridge
exceeding 590 dm is seen in several model solutions this aftn
suggests some near record temps possible. Given strong/tight model
based concensus of both upper ridge intensity and placement will
thus drop any/all fallacious pop chances throughout the period.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 135 AM EDT Wed Sep 20 2017

LIFR conditions will likely remain in place through the remainder
of the night at KFWA as light winds and generally clear skies
allow for rapid fog/stratus formation this past evening. KSBN has
been slower to drop, bouncing around on the MVFR/VFR line past
couple of hours. HI res models suggest eventually they will drop
as well. Have backed off once again closer to 00z TAF at KSBN with
slower onset vs more  amendment that was done to get ahead of the
development. Trends will be monitored and TAFs amended if
downward spiral happens sooner (or not at all).

Any fog should burn off by 14Z with VFR conditions the remainder
of the period.





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