Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 161900

Area Forecast Discussion
National Weather Service Northern Indiana
300 PM EDT Sat Sep 16 2017

Issued at 150 PM EDT Sat Sep 16 2017

Dry weather is expected to continue tonight into Sunday morning. A
weak cool front will approach the area Sunday afternoon into
Sunday evening resulting in a chance of showers and isolated
thunderstorms. This front will stall across the region for Monday
and Tuesday resulting in a continued chance of showers and a few
thunderstorms. High temperatures on Sunday will reach into the
low to mid 80s before cooling slightly into the upper 70s to lower
80s for Monday and Tuesday.


.SHORT TERM...(This Evening through Sunday)
Issued at 258 PM EDT Sat Sep 16 2017

A trough over the Northern Rockies will continue on a northeast
track into south-central Canada allowing a trailing shortwave to be
able to move through sparking off a few light, diurnal showers
across the region this afternoon. However, coverage appears too
low for a mentionable pop. Expecting a quiet overnight, but clouds
will begin to move in as a slow moving cold front approaches from
the Plains. Diurnally forced and helped along by a pre-frontal
trough, but with little instability and no shear, showers and an
isolated non-severe storm appear possible to end Sunday. Sunday
will feel a little more summer-like with above normal temperatures
in the low 80s and dew points in the mid to upper 60s.


.LONG TERM...(Sunday Night through Saturday)
Issued at 258 PM EDT Sat Sep 16 2017

The front then stalls across the region, but little forcing and a
weaker front will yield little rainfall overnight into Monday.
Shower and thunder chances increase Monday afternoon with a little
bit more forcing and some instability, but shear is once again non-
existent. The forcing for Monday slows up while Jose is near the Mid-
Atlantic and Northeast Coast so will continue the mention of showers
overnight into Tuesday especially with the coupling of the upper

A second trough rotates into Canada where a wave break occurs.
This causes a pattern change for late week where a trough develops
across the west and ridging in the east. Sensible weather, as a
result, will be warmer temperatures across the region with lesser
shower activity heading into the weekend.


.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 150 PM EDT Sat Sep 16 2017

Generally VFR conditions are expected to persist this forecast
valid period. A very weak short wave will progress across the
southern Great Lakes region this afternoon. Moisture of any
significance is very shallow in nature, and mid level lapse rates
remain very unfavorable for shower development. Cannot completely
discount a very low end potential for an isolated shower, but much
below confidence level and expected coverage for any terminal
forecast mention. A more widespread area of diurnally enhanced VFR
cu is working its way northeast from east central Illinois marking
the leading edge of weak low level theta-e advection. A more
pronounced low level theta-e ridge is expected to advect into the
region Sunday morning, and potential of pre-frontal shower
development will increase especially toward the very end and just
outside of this forecast valid period. Light south winds this
afternoon will back southeast with loss of diurnal mixing this
evening, then back to south southwest in advance of the frontal
boundary for late in the period.




LONG TERM...Roller

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