Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 200621

Area Forecast Discussion
National Weather Service Northern Indiana
221 AM EDT Thu Oct 20 2016

Issued at 721 PM EDT Wed Oct 19 2016

Rain accompanied by some thunderstorms will overspread most areas
early this morning. The heaviest rainfall along with nearly all of
the storms will be southeast of a Knox to Sturgis line. Cooler
air will spread into the area Thursday night with high
temperatures Friday afternoon only reaching the lower 50s. Cool
and dry conditions will continue this weekend.


Issued at 1238 AM EDT Thu Oct 20 2016

Added thunder southeast half of the area; mainly south and east of
Warsaw as a large area of moderate to heavy rain showers along
with elevated storms moves across this area. Increased rainfall
amounts overnight given latest model data and radar obs/trends.


.SHORT TERM...(This Evening through Thursday Night)
Issued at 250 PM EDT Wed Oct 19 2016

Decent rain event beginning to unfold for at least the southeast
half (maybe more?) of the forecast area over the next 12 to 18
hours as low pressure develops and tracks along the frontal
boundary that moved through yesterday. Increasing mid level
forcing has allowed an extensive area of mid clouds to develop and
stream northeast into the region with pockets of showers and
thunderstorms affecting east central and southeast Illinois back
into SW Missouri. Initial surge of precip will likely stay across
mainly SE sections where decreasing condensation pressure deficits
will exist as much deeper moisture arrives. Further NW will take a
bit more time to saturate with NW extent of this still somewhat
questionable with models varying on what will likely end up as a
tight gradient for rain/no rain. Have trended pops upwards most
areas especially late evening into Thursday morning. For the time
being have left thunder out, but certainly possible in SE sections
where some elevated instability may allow for pockets of embedded

Rain will begin to exit NW areas slowly through the day with
likely to categorical pops warranted SE as low will be slow to
depart as upper level trough undergoes a negative tilt. Pops
continue far SE into Thursday evening with at least a chance of
some lake effect rain showers in the wake of the system late Thurs
night into Friday in NW sections. Overnight lows will drop into
the 50s with extensive cloud cover in place. Strong cold air
advection will arrive by Thursday with highs only climbing a few
degrees from overnight lows.


.LONG TERM...(Thursday Night through Wednesday)
Issued at 250 PM EDT Wed Oct 19 2016

Drier and cooler air will reside across the region through much of
the period as high pressure slowly drifts through the area.
Near/slightly below normal temperatures will slowly moderate back
above normal by Sunday and into next week as heights slowly
increase. Next system may bring some rainfall towards the end of
the period.


.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 148 AM EDT Thu Oct 20 2016

Aviation weather conditions will continue to deteriorate through
the remainder of the overnight hours as upper level trough tracks
across the central Plains slowly shifts eastward. Widespread rain
with a few embedded thunderstorms has occurred downstream of this
feature in response to strong frontal forcing and favorable upper
level support in right entrance region of a strong upper jet
streak. Orientation of low level circulation will keep more
impressive moisture profiles confined to to northeast Indiana
where confidence in lower end MVFR cigs is higher for latter
portions of the overnight into Thursday morning. Cannot completely
rule out a period of IFR cigs at KFWA sometime in the 10-18Z
timeframe but will maintain MVFR conditions. Confidence is
somewhat lower at KSBN but will maintain MVFR cigs above fuel
alternate conditions. Cigs should improve to VFR by Thursday
evening as drier low level air advects into the area.


LM...Small Craft Advisory from 2 PM this afternoon to 5 PM EDT Friday
     for LMZ043-046.



LONG TERM...Fisher

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