Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 190925

Area Forecast Discussion
National Weather Service Northern Indiana
425 AM EST Sun Feb 19 2017

Issued at 424 AM EST Sun Feb 19 2017

High pressure building into the area will provide fair weather
today. There will be some morning clouds and fog over southern
portions of the area, but sunny skies and unseasonably warm
temperatures should return this afternoon with highs generally
in the lower 60s, except only in the 50s near Lake Michigan.

The fair weather and unseasonably warm temperatures will continue
tonight and Monday as the high moves off to the east. A weak cold
front will cause some showers as it moves into the area Monday
night and early Tuesday. Dry weather and warmer temperatures are
expected Wednesday as another weak cold front approaches. This
front will move into the area and stall Thursday possibly causing
a few showers. A strong low pressure system will move northeast
across the Great Lakes Friday causing showers and possibly thunderstorms
in our area, followed by colder temperatures and a few lake
effect snow showers northwest on Saturday.


.SHORT TERM...(Today and Tonight)
Issued at 424 AM EST Sun Feb 19 2017

Weak cdfnt extending sw from low over srn Quebec has stalled out
over our cwa and will dissipate this morning as ridging builds in
from the west. In the meantime, low level moisture advecting ne to
the south of the front has resulted in a rather large area of
stratus and fog that was overspreading our srn counties.
Diminishing wind field associated with the ridge will result in
slow erosion of stratus today. Latest HRRR suggests the
stratus/fog will reach as far north as Route 30 early this morning
and then slowly diminish late morning and early afternoon. Still
expect sufficient heating for most of the cwa to reach the 60s
today, but did lower highs a couple of degrees across the south
due to the clouds influence this morning. Light gradient will
allow a lake breeze to develop nw holding temps there in the 50s.
Sfc ridge will move east of the area tonight with weak waa
developing. Still, mainly clear skies will provide decent
radiational cooling allowing temps to fall to the mid to upr 30s
over most of the area. Some patchy fog may develop again but held
off adding to fcst attm.


.LONG TERM...(Monday through Saturday)
Issued at 424 AM EST Sun Feb 19 2017

Deep trof over the swrn U.S. will lift ne to the upr Midwest on
Monday. WAA ahead of this trof and increased gradient mixing with
S-SE flow should result in temps reaching the mid to upr 60s over
most of the area but only in the upr 50s ne where gradient flow
should back more easterly due to Lake Erie lake breeze influence.
The wkng upr trof and associated weak cdfnt will move across our
area late Monday night and/or Tue morning causing some showers as
it moves through. Still sgfnt timing differences in models on
speed of this system which precludes higher pops in this
timeframe. Flow behind this wkng trof quickly becomes zonal with
only brief CAA transitioning to WAA by Tue aftn. Aided by an
unusually warm start to the day, highs expected in the 60s.

Weak shrtwv/cdfnt movg east in the zonal flow from the nrn plains
will provide waa and decent swly low level winds Wed. This should
result in another day with near record high temps in the mid to
upr 60s across the area. The front should drop into our area Wed
night and stall out as a stronger low develops over KS. Only
slight chances of rain as the front moves in, but rain chances
increase Thu as convergence and over-running develop along the
strengthening stalled boundary. The stalling front should result
in a little cooler temps Thu, but still well above normal.

Strong low expected to lift ne to the wrn grtlks Fri and into
Quebec Sat causing showers and possibly thunderstorms in our area
Thu ngt and Fri. Showers will end Friday night as the cdfnt moves
east of our area, hwvr, some wrap around rain showers
transitioning to light lake effect snow showers psbl into Sat nw.
Temps will be much colder Saturday, but, only near normal for late


.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1232 AM EST Sun Feb 19 2017

Difficult aviation forecast with low level moisture pooling south
of weak cold front crossing the area. Satellite shows low stratus
and fog surging NE from central IL. Should stay south of KSBN but
KFWA will be a close call. Most of latest hi-res guidance shows
stratus and fog just making it to KFWA in the 09-15Z timeframe.
Stayed on the optimistic side for now given low confidence but
dense fog and IFR/LIFR ceilings are possible. Clearing expected
after 15Z though as dry air advection and diurnal mixing ramp up.
Rest of the day expected to be VFR.





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