Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 121907

Area Forecast Discussion
National Weather Service Northern Indiana
307 PM EDT Thu Oct 12 2017

Issued at 306 PM EDT Thu Oct 12 2017

Cloudy skies are expected to continue through tonight into early
Friday. Skies will become partly sunny on Friday and it will be
warmer with highs in the upper upper 60s to low 70s. Showers and
perhaps even a few thunderstorms will move into far northwest
Indiana and Michigan late Friday night into Saturday, and into the
remainder of the forecast area Saturday night into Sunday
morning. Highs on Saturday will be unseasonably warm into the mid
to upper 70s. Cooler and drier air will filter into the region
later Sunday into early next week.


.SHORT TERM...(This Evening through Friday)
Issued at 306 PM EDT Thu Oct 12 2017

Strong subsidence inversion under shortwave ridge has locked in
moist near surface layer. Depth of this moist layer per latest AMDAR
soundings 1-2 km deep suggesting extensive low stratus deck will
remain in place into tonight. A weak sfc trough draped from sw OH
wnw to central IL will lift north through the area later tonight
into Friday morning. Could see some patchy fog/drizzle in advance
and along this feature as it moves through, though coverage should
be limited with most locations remaining dry. Warm advection and
expected mix out of low clouds in wake of weak trough (from sw to
ne) in the morning/early afternoon should afford a warmer Friday
as low-mid level flow veers more southerly.


.LONG TERM...(Friday Night through Thursday)
Issued at 306 PM EDT Thu Oct 12 2017

A relatively potent shortwave trough is still on track to work west
to east across the US this weekend in progressive pattern, with the
associated deepening sfc cyclone taking a Central Plains to Northern
Great Lakes track by Saturday night/Sunday morning per latest model
consensus. Excellent moisture return/convergence within downstream
LLJ core will likely allow shower/embedded thunder coverage to
blossom from Iowa east-northeast into the lower-central Great Lakes
by later Friday night-Saturday. This strengthening baroclinic zone
will be the focus for higher PoPs during this time into our nw IN
and sw Lower MI zones, while ne IN/nw OH remains dry and
unseasonable mild within a well mixed warm sector. Rainfall
totals in excess of a half inch will be possible in sw Lower MI,
with higher amounts just north from the IL/WI border into central
Lower MI.

Trailing cold front will work through later Saturday night/Sunday
morning with additional shower chances. Transient/brief shot of
cooler/drier/seasonable air then follows into early next week as
high pressure builds in wake of trough.


.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 114 PM EDT Thu Oct 12 2017

Cigs only slowly rising today as expected and KSBN has finally
reached MVFR while KFWA still holding in IFR conditions. Expect
slowly rising cigs rest of the day. Uncertainty tonight on whether
CIGS will maintain MVFR category or drop back down to IFR with
nocturnal cooling. Remained optimistic with MVFR cigs and some BR
development but confidence low given moist low levels. Similar
uncertainty for Friday on how fast clouds will break up. Kept a
BKN MVFR deck in both terminals through end of period.




SHORT TERM...Steinwedel
LONG TERM...Steinwedel

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