Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 132309

Area Forecast Discussion
National Weather Service Northern Indiana
609 PM EST Fri Jan 13 2017

Issued at 332 PM EST Fri Jan 13 2017

There is a chance of light freezing rain overnight, mainly for
locations south of Route 24. Light icing is possible across these
areas early Saturday morning. Otherwise a period of dry weather is
in store from Saturday afternoon through Sunday afternoon. A warm
front lifting across the area Sunday night into Monday morning
will bring another potential of some freezing rain across most of
the region, which will transition to all rain on Monday. Periods
of rain will continue Monday and Tuesday with mild conditions
developing for much of next week.


.SHORT TERM...(This Evening through Saturday)
Issued at 332 PM EST Fri Jan 13 2017

Short term forecast concern will continue to focus on potential of
some freezing rain overnight into early Saturday, mainly across
southern third of the forecast area.

Low level warm advection/moisture transport will commence early this
evening as low level winds continue to veer more southerly in
response to departing low level anticyclone across the Great Lakes
region. Much of the initial isentropic lift later this evening will
be spent on low level saturation issues. Duration of more
favorable isentropic lift will also be limited by the passage of a
couple of highly sheared upper level short waves emanating from
confluent upstream upper level flow pattern. With more limited
duration to favorable advective forcing, prospects for more
significant precipitation appear to have lessened as far north as
southern portions of the forecast area. Low level flow will veer
more westerly shortly after daybreak likely cutting off
additional measurable precip chances. Freezing drizzle/light
freezing rain is still the precip type of choice, although some
possibility of mid level seeding could introduce some instances of
light sleet/light snow. With sharp moisture gradient setting up in
this type of flow pattern, have maintained a sharp north to south
PoP gradient tonight from high chance far south to slight chance
central sections. Will not issue any headlines at this time given
lower confidence in coverage and extent of freezing rain, but will
need to monitor this as even light precip amounts/light icing
could lead to some travel impacts late tonight/Saturday morning.

Chances of any light precip across the south will diminish
Saturday morning with all indications still pointing toward a lull
in precip chances Saturday afternoon through most of Sunday as
brief shot of drier low level air moves into the area in the wake
of weak northern stream upper level short wave passage.


.LONG TERM...(Saturday Night through Friday)
Issued at 332 PM EST Fri Jan 13 2017

Generally quiet weather expected for most of the day Sunday as
upper level ridging builds into the region in advance of cut-off
upper PV anomaly which will begin to eject from the Texas
panhandle. Stronger advective forcing and mid/upper level support
should be situated west and southwest of the local area to begin
Sunday although eventual ramp up of isentropic lift again for
Sunday night will result in increasing precip chances from south
to north. Primary low level moisture transport axis will still
likely be located back across the mid MS valley with some of the
warm advection induced lift again being spent on saturation
issues across local area. The potential does exist for another
instance of light icing as stronger warm advection forcing lifts
north across the area. Confidence in impacts is low at this time,
but it is possible that an advisory will be needed some time in
the late Sunday/early Monday timeframe for most of the area.

A very brief lull in precip chances is possible early Monday between
leading edge isentropic lift and eventual approach of deeper
moisture (another 1 inch PWAT axis) associated with upper trough
lifting across the Central Plains. Some decent rainfall amounts are
possible in the Monday night-Tuesday night period which may need to
be watched considering some current high water levels on area
rivers. Have not included a mention at this time, but there could be
a narrow window for sufficient elevated instability/forcing to yield
an isolated thunderstorm during this period, but chances seem quite
low. Unsettled pattern and additional light rain chances may linger
into Wednesday if slower solution (more highly phased idea of EC)
evolves) verifies.

Other than the rain showers to begin the week, the biggest story
will be the much above normal temperatures. Highs on Tuesday should
range from upper 40s northwest to mid to upper 50s far southeast. A
brief cool down behind phasing system is expected mid week, with
moderating temperatures back into the 50s anticipated by Friday.


.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 609 PM EST Fri Jan 13 2017

Dry entrainment through srn periphery of strong arctic high centered
through the nrn lakes will keep precipitation focused south of the
terminals through cntrl/srn IL/IN this period. Some uptick in mid
level moisture flux seen Sat morning which should yield eventual
mvfr flight conditions invof of kfwa but vfr conditions expected to
persist at the ksbn terminal throughout the period.


LM...Small Craft Advisory until 4 PM EST this afternoon for LMZ043-



SHORT TERM...Marsili
LONG TERM...Marsili

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