Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 191120

Area Forecast Discussion
National Weather Service Northern Indiana
620 AM EST Sun Nov 19 2017

Issued at 620 AM EST Sun Nov 19 2017

Mostly cloudy breezy and cold today with highs this afternoon in the
mid 30s.

The rest of the upcoming holiday week will be seasonably cool and
dry through Thanksgiving Day.


.SHORT TERM...(Today and Tonight)
Issued at 206 AM EST Sun Nov 19 2017

Much quieter weather in store as LES winding down this morning
only sensible weather concern. Both KIWX and KGRR indicating
diminishing trends in LES recently which the latest HRRR run has
captured nicely. Despite the current downward trend...forecast
soundings still indicating unidirectional NW flow beneath 5Kft
inversion lending marginal support for continuing low chance POPs
through the morning hours before winds back to a more westerly
direction as surface ridging builds into the TN valley. This will
lead to clearing skies this afternoon away from the lake but
expect little change in temperature given decent low level CAA.
Despite clear skies tonight...high pressure center to the south
will leave enough of a gradient over the area to mitigate
decoupling of the boundary layer and more substantial radiational
cooling which should leave lows in the mid-upper 20s.


.LONG TERM...(Monday through Saturday)
Issued at 206 AM EST Sun Nov 19 2017

A generally quiet weather pattern to prevail through the long
term period. High pressure slides off to the Carolinas on Monday
bringing a milder but quite brisk SW return flow. So while highs
will warm back to 45-50F...apparent temps not expected to get out
of the 30s. Northern stream system moving across southern Ontario
will bring a cold front through the area Tuesday afternoon.
Latest model trends showing high pressure drifting further out
into the Atlantic but still have gulf moisture cut off.
Operational GFS now hinting at narrow band of precip clipping our
far NE CWA and this signal has found its way into the blend...but
other models remain dry and only a couple of the GEFS members
showing anything more than 0.01 so will smooth this to a dry fcst.
Signal for LES in NW fetch behind front Tuesday night into
Wednesday morning remains weak so will still opt for keeping
forecast dry here as well. Another shot of cold air behind this
front will have lows dropping into the 20s with highs in the mid
30s Wednesday and upper 30s to near 40 for Thanksgiving. Another
northern stream system moves into the northern great lakes by the
end of the period and bring a low chance for precip to the
forecast area.


.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
Issued at 620 AM EST Sun Nov 19 2017

General VFR expected this period. Expansive stratocu shield remains
locked in attm within maximized low level thermal trough. However
this will erode out quickly this aftn given dry entrainment aloft
out of deep subsidence layer and collapsing low level thermal
trough. Until then wrly breezes will gust to 20kts for a time this


LM...Gale Warning until 4 AM EST early this morning for LMZ043-046.




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