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Area forecast discussion 
National Weather Service northern Indiana
554 am EST Monday Feb 8 2016

issued at 424 am EST Monday Feb 8 2016

Accumulating snowfall is expected across much of the Great Lakes
through at least Thursday. Amounts during any one period will be
generally light...but the long duration of the event may allow
areas near Lake Michigan to see between 6 and 12 inches of snow
by the time Thursday morning arrives. A blast of Artic air is
poised to impact the region by the weekend with afternoon highs
struggling through the teens and lows in the single digits.


Short term...(today through Wednesday night)
issued at 424 am EST Monday Feb 8 2016

Primary focus from near term through Wednesday night is to delay onset of
primary les event owing to slow southwestern Great Lakes fujiwhara with conserted
cold pool plunge delayed. Initial sheared environment and modest
differentials to provide some lake enhancement of synoptic
moisture/Arctic frontal shsn with episodic waves of enhanced
deformation/DCVA emanating from the upper MS valley region. Until
180 knots ulvl jet presently topping ridge/far northern British Columbia drives southward
towards lower MO valley on Tuesday will les ingredients to congeal. Lake
effect cape and lake induced eql appear broadly ramped with
respect to time and peak on order of 400 j/kg and 13 kft Wednesday after
respectively. Anticipate a few les bands to become well
established and persist Tuesday night into Wednesday...if not into first
half Wednesday night before downturn starts. Total accums establish well
within range of multimodel Cobb averages with/without compaction
and close to or slightest upward nudge over prior forecasts and
consistent with trends.


Long term...(thursday through sunday)
issued at 424 am EST Monday Feb 8 2016

Deep upper level trough will begin to finally pull away from the
area. Northwest flow will persist through at least the first half of
Thursday with high chance to likely probability of precipitation warranted for light quantitative precipitation forecast/accums
as Delta t's in the middle 20s. Alignment of dgz and best lift will not
be fully meshed but still enough to hold onto higher probability of precipitation than
depicted by superblend of models.

Low level flow and thermal contributions will become more
challenging after Thursday with regards to surface temperatures as well
as lake effect potential. Medium range models consistent with regards
to -28 to -34 c core of 850 temperatures accompanying deep upper low.
However...where this will end up is less certain. 12z runs of GFS
and European model (ecmwf) were more towards the NE states. 00z GFS hold with this
idea, but 00z European model (ecmwf) brings core of cold air into the eastern Great
Lakes. At this point...will maintain previous idea of slight chance to
chance probability of precipitation closer to the lake. Enough confidence in colder trend to
lower temperatures a few degrees Friday into Sat. If core of colder air does
come further west...then a significant drop in temperatures will be


Aviation...(for the 12z tafs through 12z Tuesday morning)
issued at 547 am EST Monday Feb 8 2016

High confidence in deteriorating flight conditions through the
period with the greatest impacts occurring tonight and beyond.
MVFR conditions will occur through much of the day as snow showers
affect both sites. A greater concentration of snow shower
activity as well as trend towards potential IFR conditions will
take place after 6z Tuesday. Further changes in tafs will be needed
as situation unfolds.


Iwx watches/warnings/advisories...
Lm...Small Craft Advisory from 1 am Tuesday to 10 am EST Thursday for



short term...Murphy
long term...Fisher

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