Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 221804

Area Forecast Discussion
National Weather Service Northern Indiana
104 PM EST Wed Nov 22 2017

Issued at 1240 PM EST Wed Nov 22 2017

Lake effect clouds will gradually diminish late this afternoon
into this evening. Clouds will increase again overnight into early
Thanksgiving morning as a weak system approaches for the west, but
clouds are expected to diminish again for Thanksgiving afternoon
as this system pushes eastward. Dry weather is expected for
tonight through Friday afternoon, with only a small chance of
light rain Friday night. Low temperatures tonight will drop into
the mid 20s. High temperatures on Thanksgiving afternoon will
reach into the lower 40s.


.SHORT TERM...(Today and Tonight)
Issued at 310 AM EST Wed Nov 22 2017

Lake effect cloud cover taking hold across nearly all of the
forecast area on decent NE flow. Despite the favorable flow and
Delta T values, no precip has been noted thus far with dry low
levels and inversion height around 3500 ft. HRRR shows some light
shower activity possible mid morning into early afternoon, but also
shows lighter precip further north at this time which isn`t panning
out the best. By this afternoon, flow will quickly become more
westerly and cloud deck should begin to erode as drier air works in.
A cold day will be in store with highs only in the mid 30s. Another
fast moving wave will pass through the region with only an increase
in mainly mid clouds expected. Lows tonight will fall back into the
mid to maybe upper 20s.


.LONG TERM...(Thursday through Tuesday)
Issued at 310 AM EST Wed Nov 22 2017

Upper level flow will rapidly transition through a zonal flow on
Thanksgiving day to amplified flow by Friday into Saturday in
advance of the next front and stronger short wave which will be
located across western Wisconsin by 00Z Sat. While dry on
Thanksgiving, it will be on the cooler side yet with highs in the
upr 30s to lower 40s, warming into the 40s to lower 50s Friday with
some potential for even higher temps if enough mixing and sunshine.
Quick shot of light showers possible with passage mainly Friday
night. Temps will cool slightly behind the first wave Saturday with
highs in the mid to upper 40s, with a secondary disturbance and cold
front moving across Sat afternoon sending highs back to similar
levels as Thanksgiving.

Heights increase more dramatically into mid week as deeper trough is
carved out in the Plains. Models vary on chances for precip with
ECMWF keeping things dry here vs GFS showing another area of showers
to accompany the front just outside the current period. Highs should
shoot above normal once again by Tuesday with highs upper 40s to
lower 50s.


.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 100 PM EST Wed Nov 22 2017

Lake effect low clouds will gradually diminish/shift east of the
terminals late this afternoon into early this evening as low
level winds back in response to departing anticyclone. Cigs with
lingering lake effect stratocu are primarily VFR. Otherwise,
departure of low clouds will be replaced by increasing mid clouds
overnight into early Thursday in response to next mid level short
wave. These clouds should exit for Thursday afternoon. Light
southwest winds will develop this evening, with diurnal mixing and
tightening gradient promoting southwest winds of 10 to 15 knots
later Thursday. Some gusts to 15 to 20 knots will also be
possible Thursday afternoon.




LONG TERM...Fisher

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