Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 221730

Area Forecast Discussion
National Weather Service Northern Indiana
130 PM EDT Sat Oct 22 2016

Issued at 121 PM EDT Sat Oct 22 2016

Quiet weather will dominate the remainder of the weekend. Expect
clear to partly cloudy skies through Monday. Lows tonight will be
in the 40`s. Highs Sunday will be in the mid-upper 60`s and low
70`s. On Monday, highs will fall back into the 50`s and low 60`s.


.SHORT TERM...(Today and Tonight)
Issued at 342 AM EDT Sat Oct 22 2016

Lake effect rain showers will continue to wind down this morning,
with quiet conditions than persisting into tonight.

Scattered lake effect rain showers persist early this morning.
Thermally induced lake low level troughing and nocturnal enhancement
to low level convergence across southern Lake Michigan has allowed
for continued anchoring of lake effect rain shower activity across
NW La porte county  as of 07Z. Weaker showers also should be working
inland across Berrien county through daybreak. Some weak increase
in upper forcing over the next few hours should also continue to
overspread the southern Great Lakes as a sheared vorticity max
associated with eastward migration of upper jet core approaches.
Passage of this vort max and break down of stronger nocturnal
convergence should allow for quicker deterioration of lake effect
rain showers toward 12Z. Scattered sprinkles/light rain showers
may persist for a few hours after daybreak in closer proximity to
Lake Michigan shoreline. Some patchy frost will be possible
through 13Z away from lake effect clouds across the northeast and
far southwest sections, but just enough weak low level mixing
should tend to limit coverage.

Otherwise dry conditions expected for the remainder of the forecast
area today. Gradual eastward shift to upstream ridge axis will usher
in a strong low/mid level baroclinic zone today. Mid level WAA
induced clouds developing across the mid-upper MS Valley will
overspread the area late morning into this afternoon which may give
at least a period of mostly cloudy skies northern half as this
forcing shifts from west to east. Temp forecast somewhat tricky
given periods of cloud cover and competing effects of warm advection
and lowering mixing depths this afternoon. Taking all into
consideration, temps should be at least a few degrees warmer most
locations today from near 60 southwest to lower 50s far northeast.
Light southwest return flow to become established tonight with
slightly milder mins into the lower to mid 40s for most


.LONG TERM...(Sunday through Friday)
Issued at 342 AM EDT Sat Oct 22 2016

The next eastern Pacific jet streak/short wave across Pacific
northwest this morning will quickly translate eastward over the
next 36 hours dampening the upstream ridge, and will eventually
track across the Great Lakes region on Sunday. A brief but fairly
intense shot of low level warm advection will precede frontal
boundary with this system that may allow portions of the area to
make a run at the upper 60s or around 70 Sunday afternoon (warmest
southwest). With better DPVA remaining to the north of the area
and a stratospheric intrusion of much drier air into the mid
levels, will keep a dry forecast going Sunday/Sunday night. Some
guidance suggests some brief light precip potential Sunday night
behind the front but given lack of moisture and very shallow
moisture profiles will refrain from any mention.

A fairly seasonable temperature pattern to then set up for much
of the Monday-Wednesday period. Warm advection will increase once
again mid week in advance of next advertised more robust short
wave approaching the area, but increased clouds/precip potential
should limit temp increase somewhat. Have maintained low warm
advection wing-type PoPs Tue/Tue night, with PoPs ramping up more
significantly Wed/Wed night as upper trough and stronger low level
convergence fields come into play. Guidance displaying some
significant spread in exact track of this wave and associated sfc
reflection so will continue to omit thunder mention at this time,
but maintain likely PoPs from west to east Wed/Wed night.

Not much change made to the remainder of the forecast with some
indications another fropa may be possible toward the end of the
forecast period associated with more active northern stream. Another
period of above normal temps should precede this front, with
duration dependent on southward penetration of this boundary in the
Day 7-8 timeframe.


.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 121 PM EDT Sat Oct 22 2016

A building ridge of high pressure will keep conditions primarily
VFR through the TAF period. Some of the model guidance have BR
developing at both sites towards 10-12Z Sun morning, but only
have vis dropping to 5-6 SM. Left out of the TAF for now given low
confidence and limited potential impacts.




SHORT TERM...Marsili
LONG TERM...Marsili

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