Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 260545

Area Forecast Discussion
National Weather Service Northern Indiana
1245 AM EST Sat Nov 26 2016

Issued at 635 PM EST Fri Nov 25 2016

Some Light rain or drizzle is possible along and north of highway
overnight as an upper level disturbance crosses the region. Lows
will primarily be in the lower to middle 30s. Dry conditions are
expected Saturday, though cloudy skies will likely prevail at
least into midday. It will gradually become warmer with highs in
the lower to middle 40s Saturday and into the upper 40s to lower
50s on Sunday. Periods of rain will move through the area Monday
and Tuesday as a strong low pressure system moves into the Upper
Great Lakes.


.SHORT TERM...(This Evening through Saturday)
Issued at 341 PM EST Fri Nov 25 2016

Again for at least third day in a row have further squelched
diurnal range with warmer lows/cooler max temps in near/short term
periods. Expansive/thick cloud coverage across region under
cyclonic low level flow/thermal trof overhead. Anticipate some
light response to passage of upstream shortwave over southern
Wisconsin at present to pivot/translate eastward through CWA this
evening...especially along/north of US 30 in tandem with 50-70m/12
hour mid level height fall centroid. In wake expect cloud cover to
become trapped beneath subsidence inversion with breakout likely
postponed until midday Sat and have reigned in max temps


.LONG TERM...(Saturday Night through Friday)
Issued at 341 PM EST Fri Nov 25 2016

Low amplitude ridging surface/aloft should finally allow for a
more substantive boundary layer warming on Sunday. This in advance
of primary focus/progression of deepening/congealment of complex
northern stream systems into Northern Plains by daybreak Monday.
Warm air advection/burgeoning baroclinic leaf into at least
western CWA early Monday as eastern CO surface low on Sunday
ejects northeast/deepens into eastern SD by 12 UTC Mon. Secondary
shortwave energy injected through base of trof/northern TX to
likely elicit strong cyclogenesis along tail of frontal zone with
surface low CYCLONICALLY rotating from southern plains Mon into
Lower Ohio Valley Monday evening/night for episode of extreme
GOMEX moisture flux convergence/lift with heavier/more widespread
rainfall event late Mon aft into Mon night. At this time have
withheld mention of convection, given disparate MUCAPE fields of
EC/GFS and uncertainty of low level jet placement/focus.
Thereafter little change in blended approach. Intrusion of colder
air with orphaned Great Lakes cyclonic flow along with lake
enhancement could bring mix ra/sn showers by late Wed night as
near surface wet bulb temps cool sufficiently. Potential upset
would be significance of presently discounted outlier Can
depicting strong tertiary cyclogenesis well west of Appalachian
chain late Wed night/Thu.


.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1238 AM EST Sat Nov 26 2016

Pattern should finally start to break down for this forecast cycle
with passage of the last in a series of short waves now beginning
to depart the Great Lakes region. Some enhanced subsidence behind
this short wave has led to pocket of clearing across northwest
Indiana, although would suspect that flow off Lake Michigan and
lingering shallow lake induced instability will keep low clouds
in place for terminals this morning. Drier air advecting
southeastward should result in continued improvement with cigs
this morning, although lowering inversion heights still pose some
lower end threat for cigs below 2k feet over the next several
hours. Light southwest flow to develop by this evening as
anticyclone drifts southeast of the area, with an increase in mid
level clouds late. Looking ahead, may have to consider some fog
mention just beyond this forecast valid period for Sunday morning
depending on extent of mid level cloudiness.




LONG TERM...Murphy

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