Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 261747

Area Forecast Discussion
National Weather Service Northern Indiana
147 PM EDT Sun Mar 26 2017

Issued at 1115 AM EDT Sun Mar 26 2017

Occasional showers and a few thunderstorms can be expected through
the remainder of the day into early this evening. Conditions will
dry out later this evening into early Monday, but another system
will bring renewed rain chances Monday afternoon into Monday
night. Highs today and Monday will be in the upper 50s to the
middle 60s. Lows tonight will drop into the mid to upper 40s.


Issued at 1115 AM EDT Sun Mar 26 2017

Overall no major changes to previous forecast/grids. Rain showers
continue to lift north across the forecast area late this morning
with greatest concentration across the north in stronger DPVA zone
with lead vort max. Showers to extend southward across central
Indiana well located with axis of more pronounced 925-850 hPa
moisture convergence, with short term progs indicating this axis
shifting across far northeast Indiana/northwest Ohio this
afternoon. A more compact upper vort max across west central
Illinois will eventually shift eastward across northern Indiana
late this afternoon/early this evening. This vort max will be
associated with slightly steeper mid level lapse rates as pocket
of -18 to -20 deg C air at 500 hPa lifts northward from southern
Indiana. Already beginning to see some uptick in lightning strikes
across southeast Indiana in association with this cold pocket,
which should reach at least eastern half of forecast area by late
afternoon. Did heighten thunder wording to chance this afternoon,
especially across the southeast where pocket of 250-750 J/kg of
surface based instability is expected. In terms of temperatures, a
fairly dramatic spread in temps across the area from low to mid
40s east to mid to upper 50s west late this morning, but do
expect as warm frontal feature lifts northward this afternoon that
temps will become more uniform late.


.SHORT TERM...(Today and Tonight)
Issued at 418 AM EDT Sun Mar 26 2017

An upper low and associated surface low was over northeast Missouri
and was moving northeast early this morning. The front that was over
northwest Indiana yesterday morning had sagged south and extended
from Lafayette to Muncie early this morning. A northeast to east
flow out of Canada across the chilly waters of Lake Erie with
temperatures in the 30s was spreading very cool air over far
southern Lower Michigan and northwest Ohio. Upstream aircraft
soundings showed a warm layer up to 17C near 900 mb. Given the low
track northwest of the area, favor a mixing out of the shallow cold
layer before cooler air spreads back into the area behind the low
tonight. Rain with embeded storms will spread northeast today.
Severe storms are not expected, although locally heavy rain is
possible. Rain will end tonight, with temperatures staying mild.


.LONG TERM...(Monday through Saturday)
Issued at 418 AM EDT Sun Mar 26 2017

The next in a series of upper level systems will eject northeast out
of the main upper trof and spread rain back across the area by late
Monday. Thermal profiles indicate all rain for this event. A third
and stronger system will arrive late this week.  In the interim
between the second and third systems, very cool air will spread
across the area during the middle of the week as a large high
pressure area builds south out of Canada. Lows Tuesday and Wednesday
nights will dip into the 30s. Rejected some 20s for now showing
up in the GFS MEX guidance. Kept the precipitation all rain for
now; however, the colder GFS BUFKIT was favoring a wintry mix at
the start of the event Thursday.


.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
Issued at 139 PM EDT Sun Mar 26 2017

IFR conditions to slowly improve, at least for a short period, as
mixing occurs with northward moving frontal boundary. Scattered
showers expected at both sites the remainder of the afternoon.
Chance of thunder exists mainly at KFWA where colder air aloft
will help with instabiliity. Have left out of TAF for now
given expected isolated nature.

Inversion will take hold tonight and likely allow for stratus
development again with low end MVRF into IFR conditions expected
late evening into much of tomorrow as low pressure tracks




SHORT TERM...Skipper
LONG TERM...Skipper

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