Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 261713

Area Forecast Discussion
National Weather Service Northern Indiana
1213 PM EST Sat Nov 26 2016

Issued at 333 AM EST Sat Nov 26 2016

Cool and cloudy conditions will persist today with highs in the 40s.
Expect less clouds on Sunday with highs near 50. Widespread moderate
rain is expected on Monday as a large low pressure system moves into
the Great Lakes. Temperatures will be relatively mild through the
first half of next week but will cool back down by the end of the


.SHORT TERM...(Today through Sunday)
Issued at 333 AM EST Sat Nov 26 2016

Main concern for the short term will be cloud trends and subsequent
effect on temps. Drizzle and light rain currently exiting with
modest shortwave ridging/AVA generating increasing subsidence across
our area. Pocket of clear skies even noted over our SW CWA. Relative
lack of upstream stratus does raise some concern for today`s cloud
forecast but latest model soundings (including hi-res/rapid update)
show just enough moisture trapped under strengthening subsidence
inversion to yield mostly cloudy skies through at least the morning.
This idea is supported by latest satellite trends which show SW
cloud gap shrinking. Added contribution of Lake MI in WNW flow will
likely keep our NE half cloudy for much of the day. Some indications
that low clouds may dissipate in our SW by the afternoon as flow
gradually backs and drier air is advected into the area. However,
models also show increasing mid/upper clouds during that time as a
highly-sheared wave passes through (already a fairly thick cirrus
shield upstream). Will therefore hold with partly sunny/mostly
cloudy forecast and highs in the 40s.

Expect a general clearing trend through Sunday as low level flow
gradually backs and strengthens ahead of next system. Overnight lows
may be a degree or two colder tonight given less cloud cover but
highs on Sunday should easily recover to around 50F given 925mb
temps approaching 5C.


.LONG TERM...(Monday through Friday)
Issued at 333 AM EST Sat Nov 26 2016

Attention for next week then turns to high amplitude and large
wavelength trough developing over much of North America. Pair of
strong Pacific upper jet streaks currently just offshore (and a
third still well upstream) will carve out this large height anomaly
and support strong cyclogenesis over the Northern Plains/Upper
Midwest. First chance of rain will arrive early Monday morning with
leading wing of isentropic ascent and moisture advection. Best
chances for widespread moderate rain will then arrive Monday evening
and persist into the overnight as secondary CVA bullseye moves
overhead along with good upper divergence and copious moisture. 50-
60 kt LLJ pushes 850-700mb mixing ratios to around 6 g/kg with PW
values just over 1 inch (near climo max for this time of year).
Remain highly skeptical of thunder chances with limited midlevel
lapse rates/MUCAPE though. Lowest 2km also relatively cool with
surface temps/dewpoints near 50F at best. Will leave out thunder
mention but do expect QPF totals near one inch for many locations
given ample forcing and moisture.

Dry slot moves overhead on Tuesday. Left some very low chances in
Tuesday morning but even those could be removed with abrupt push of
dry air advection and isentropic descent. Also left some slight
chances in east on Wed but most of the latest guidance is dry for
our CWA during that time with baroclinic zone and final wave setting
up well SE of our area. Broad cyclonic flow then sets up over the
Great Lakes during the end of the week. This will likely bring
another extended period of cool and cloudy conditions with periodic
light lake-enhanced precip. Temps will hover in the 30s and could
see some snow mix in at times, though chances for any accumulation
appear very low at this point. Likely just another stretch of
overcast skies and light drizzle. Did bump up cloud cover during
this period with just low chance PoPs near the lake.


.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1208 PM EST Sat Nov 26 2016

Lingering MVFR ceilings are expected to continue at KSBN while
conditions have improved at KFWA to VFR criteria. Overnight
ceilings will continue to rise for the entire area including
places that are currently in MVFR flight conditions. Winds will
remain around 10 kts for the forecast period and will gradually
shift from west to southwest overnight.





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