Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 151142

Area Forecast Discussion
National Weather Service Northern Indiana
641 AM EST Wed Nov 15 2017

Issued at 409 AM EST Wed Nov 15 2017

 A cold front will bring widespread showers today with highs
generally in the mid to upper 40s. This will be followed by cooler
and mainly cloudy conditions into Thursday. Light lake effect
rain and snow showers are possible tonight, mainly along and north
of the toll road. Another storm system will move through later
Friday into Saturday with periods of rain and milder temperatures.


.SHORT TERM...(Today and Tonight)
Issued at 409 AM EST Wed Nov 15 2017

A warm front is currently migrating northeastward towards our CWA,
generating scattered rain showers along/ahead of it. Expect this
front to continue lifting through our CWA this morning. As moisture
transport increases along the LLJ, we`ll see rain showers become
more numerous. The system cold front will track eastward into our
CWA a bit later today, and with it categorical pops. While things
may be initially scattered, expect them to consolidate as the day
wears on into a more defined and progressive area of precipitation.
Expect we`ll encounter the dry slot by late this afternoon and early
this evening. This will cut precipitation to more of a
sprinkles/flurries situation instead of more substantial shower
activity, mainly focused along/north of I 80-90 where lake
enhancement kicks in. Have these sprinkles/flurries tapering off by
Thursday morning as dry air overcomes any ability to produce
precipitation. Cloud cover will be on the decrease tonight for the
southwest as the dry slot moves in, allowing for low temperatures to
drop into the low 30s. Further north and east, expect lows in the
mid-upper 30s. High temperatures will be in the 40s and may even
reach 50F in the southwest today.

In other short term news, winds will kick up ahead of and behind the
front, veering from south-southeast to the northwest overnight.
Gusts up to 30 mph are possible, especially near the lakeshore.


.LONG TERM...(Thursday through Tuesday)
Issued at 409 AM EST Wed Nov 15 2017

Thanks to high pressure, dry weather is expected on Thursday and
Thursday night. Cloud cover may linger on northwesterly winds and
lake enhancement, which will keep highs around 41F. Earlier in the
day may be breezy, but winds should lighten up by late afternoon as
the pressure gradient slackens. Lows will be in the upper 20s and
low 30s.

Our next chances for precipitation look start Friday afternoon, with
our forecast area on the nose of a LLJ and in the region of
subsequent warm air/moisture advection. Models still largely
disagreeing on things in terms of strength/timing of this system,
unfortunately. The surface low is forecast to lift northeastward
across our area Saturday as it deepens to anywhere from 978-986 mb
(depends on the model) over Lake Huron/Southern Ontario. With
LLJ/anomalous moisture per Pwats of over 1 inch, and sufficient
upper level support from the left exit region of a 300mb jet-kept
the higher consensus pops through Saturday afternoon. Also kept the
going slight chances for thunder, given models suggest around 100
J/Kg of MUCAPE Saturday.

Late Saturday afternoon into Sunday it looks as if we are dry
slotted, and eventually left with the lingering upper level trough.
Ambient lift from this trough, combined with 850mb temps falling to
-9 to -12C suggest the potential for lake effect rain/snow showers
through Sunday night. Morning highs on Saturday will be in the upper
40s and low 50s, then fall into the upper 30s and 40s by late
afternoon. Lows Saturday/Sunday night will be bitter, ranging from
the low to mid 20s.

High pressure builds in for the remainder of the long term, with dry
conditions and highs in the upper 30s and 40s Monday into Wednesday.
Lows will be in the upper 20s and 30s.


.AVIATION...(For the 12Z TAFS through 12Z Thursday Morning)
Issued at 641 AM EST Wed Nov 15 2017

VFR flight rule in the process of gradually decay in response to
ramping moisture advection swd of low pressure winding up across the
nrn lakes. However top down saturation slowed as upstream low level
moisture flux pinches off with ewd extent and denoted in general ewd
erosion seen in reflectivity echoes early this morning. Nonetheless
overlap of frontal based forcing and narrowed moisture ribbon will
yield a several hour period of -shra and greater saturation to
promote widespread MVFR conditions mid to late morning.


LM...Small Craft Advisory until 7 PM EST Thursday for LMZ043-046.




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