Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 151718

Area Forecast Discussion
National Weather Service Northern Indiana
118 PM EDT Sat Jul 15 2017

Issued at 110 PM EDT Sat Jul 15 2017

Dry and pleasant weather will persist today as high pressure
drifts south across the Great Lakes region. There is a chance for
a shower or thunderstorm Sunday as a weak cold front moves across
the area before dry conditions return Monday. Highs will be mainly
in the 70s through Monday.


.SHORT TERM...(Today and Tonight)
Issued at 304 AM EDT Sat Jul 15 2017

Surface high pressure centered over N IL tonight providing clear
skies...light winds...and low humidities. An ideal mid July day in
store for today as these conditions will continue as ridge drifts
slowly south. Clouds will begin filling in over the northern CWA
Saturday night as short wave energy drops down in NW flow and will
dig into southern Ontario and the far northern great lakes late
Saturday night. Otherwise a rather comfortable night for this time
of year as overnight lows drop into the lower 60s.


.LONG TERM...(Sunday through Friday)
Issued at 304 AM EDT Sat Jul 15 2017

Short wave trough will continue to dig southeastward into SE
Ontario and eastern great lakes Sunday. Weak surface frontal wave
and associated frontal boundary will accompany this disturbance
and generate just enough mass convergence acting on a modestly
unstable airmass...afternoon CAPE`s around 1500J/ bring a
chance for showers/thunderstorms for an otherwise moisture lacking
system. Another Canadian high builds into the great lakes region
behind this disturbance which will re-enforce seasonably cool and
less humid conditions for Monday. Eastward expansion of upper
ridge will have temperatures quickly warming back to normal on
Tuesday and also enhance/strengthen northern stream flow which
will set the stage for multiple rounds of ridge-riding convective
complexes. Problem is that medium range models continue to differ
on extent of ridge expansion and resulting position of northern
stream flow...European and Canadian ensembles have ridge axis
focused further east over the MS river valley...a warmer and drier
solution for our area which would have temps approaching 90 on
Wed...while GEFS staying with a more plains centric
position...limiting the mid week heat and bringing precip in as
early as Wednesday. Blended POP grids are a mess as a result and
will continue to attempt trimming back where feasible until better
model consensus is realized.


.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 109 PM EDT Sat Jul 15 2017

Stubborn stratus deck has finally eroded from over KFWA. Pockets
of SCT to occasionally BKN cu remain, but satellite data shows
increasing subsidence causing coverage and depth of clouds to
slowly decrease. High clouds will begin to move in later this
evening into the overnight from upstream convection which will
move SE, but likely weaken well before reaching the area.

Chances for showers/storms rather limited with most likely area of
development occurring SE of KFWA near/just outside the forecast
period. No mention of precip in the TAFs as a result.





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