Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 171709

Area Forecast Discussion
National Weather Service Northern Indiana
1209 PM EST Tue Jan 17 2017

Issued at 1159 AM EST Tue Jan 17 2017

Cloudy skies and perhaps a few light showers or
drizzle is possible this afternoon and tonight. Temperatures will
be mild into the 40s to and low 50s in southern portions of the
forecast area. Mild tonight with lows in the 30s. High pressure
then builds in for Wednesday and Thursday with highs into the low
to mid 40s each day. Mild and at times wet weather pattern is
expected Friday through early next week.


.SHORT TERM...(Today and Tonight)
Issued at 305 AM EST Tue Jan 17 2017

Potent shortwave and attendant sfc reflection over northern IL as of
08z will translate ene through the Lower Great Lakes early this
morning. Shot of mid level DCVA, convergence, weak elevated
instability, and appreciable moisture will continue to support
showers and possibly a rumble of thunder as this feature moves
through. Brief heavier rain onto frozen ground could generate some
localized flooding early this morning.

Eastward exit of deeper moisture/ascent will allow for a drying
trend mid morning into afternoon, though cannot rule out some
patchy drizzle/light showers given lingering low level
moist/cyclonic flow. Mild otherwise with main focus through the
morning on the potential for dense fog across far northern
IN/lower MI near weak gradient/sfc low track. Have the potential
for locally dense fog mentioned in the HWO and will monitor VIS/Ob
trends for a possible advisory this morning (best chances for sig
VIS restrictions across nw IN/lower MI).

A secondary northern stream shortwave will drop through tonight
bringing some resurgence in light showers/drizzle given brief PVA
surge and what appears to be sufficient lingering moisture depth.
Ongoing cold advection and resulting weak mixing should keep
widespread fog from reforming overnight. Cooler otherwise will temps
falling into the 30s.


.LONG TERM...(Wednesday through Monday)
Issued at 305 AM EST Tue Jan 17 2017

Ridging will provide fair wx and moderation into Wednesday and
Thursday. The associated subsidence/drying aloft is expected to
break up low clouds leaving at least a partly cloudy sky by
Wednesday afternoon/Thursday.

A highly anomalous blocking ridge of high pressure in the mid-high
levels will set up across Canada Friday into next weekend, while a
very active/strong pacific jet sends a couple of slowing storm
systems east into the middle of the country (before
occluding/weakening northeast). The lack of any cold air across
eastern NOAM will no doubt result in above normal temps through this
period, though clouds/rain/easterly low level flow could limit highs
somewhat Friday, Sunday, and Monday. A period of light rain looks
likely sometime Thursday night/Friday as weakening deformation axis
with initial piece of pacific energy attempts to survive north into
block. Brief period of southwest flow and dry conditions on Saturday
could allow temperatures to overachieve before better rain chances
arrive later Sunday/Monday on northern fringe of deep occlusion
likely emerging into the TN/OH Valleys.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1159 AM EST Tue Jan 17 2017

Low level clouds and mist will keep ceilings below 1 kft for the
majority of the forecast period. As the front approaches an
isolated chance of rain is possible for the afternoon and evening.
Some improvement to flight conditions is possible by tomorrow
morning as ceilings should rise up to low MVFR flight criteria.




SHORT TERM...Steinwedel
LONG TERM...Steinwedel

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