Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 171128

Area Forecast Discussion
National Weather Service Northern Indiana
628 AM EST Tue Jan 17 2017

Issued at 305 AM EST Tue Jan 17 2017

Rain showers with areas of fog and possibly a rumble of thunder
will continue early this morning as low pressure tracks into the
lower Great Lakes. Cloudy skies and perhaps a few light showers or
drizzle then by this afternoon and tonight. Temperatures will be
mild into the 40s to mid 50s today, with lows into the 30s
tonight. High pressure then builds in for Wednesday and Thursday
with highs into the low to mid 40s each day. A mild and at times
wet weather pattern is then expected Friday through early next


.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 12Z TAFS through 12Z Wednesday Morning)
Issued at 625 AM EST Tue Jan 17 2017

Bulk of rain ahead of cdfnt should move east of the terminals by
or shortly after start of taf period but ifr conditions expected
to predominate much of this taf period as moist low level cyclonic
flow conts. Some -dz still psbl at times today and sct -shra
likely in the area tonight as another upr level low moves
through. Some improvement to flight conditions expected late
tonight as this system moves east into OH.




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

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