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Area forecast discussion 
National Weather Service northern Indiana
649 PM EST Tuesday Nov 25 2014

Synopsis...
issued at 316 PM EST Tuesday Nov 25 2014

Partial clearing in cloud cover is expected this evening along
with light winds. High clouds will move back in on Wednesday ahead
of the next system passing across Illinois. No precipitation is
expected until late Wednesday night when lake effect snow showers
will be possible across far Southern Lower Michigan and parts of
northwestern Indiana. Low temperatures tonight are expected to
drop in the lower to middle 20s. Highs Wednesday will climb to the
lower to middle 30s.

&&

Update...
issued at 635 PM EST Tuesday Nov 25 2014

Updating to increase cloudiness overnight and into Wednesday morning as
diminishing winds should help trap low clouds beneath subsidence
inversion overnight... with light easterly low level flow developing
Wednesday probably advecting same cloud deck back to the west. Current
temperatures about 5f above forecast mins and left in tact as any breaks
could allow for that much of a fall.

&&

Short term...(this evening through wednesday)
issued at 312 PM EST Tuesday Nov 25 2014

No major weather concerns for the period as inversion heights
will continue to lower...flow shifts more SW and moisture
diminishes further. Share concerns of previous shift with
potential for inversion trapping low level moisture and allowing for
slow demise or even some redevelopment of stratus if skies do
manage to clear some. Have continued with a downward trend into
this evening. And then slowly increase clouds later tonight into
Wednesday. Thickening high clouds during the day Wednesday will
yield a mostly cloudy to cloudy day as low pressure tracks out of
the plains into NE Missouri by Wednesday afternoon. Any rain
chances will remain well removed from the area warranting removal
of any probability of precipitation Wednesday afternoon.

In terms of temperatures...lowered overnight lows a hair tonight with
clearing in the evening. Weak southeast flow will allow for slightly warmer
air to arrive on Wednesday with temperatures making a run for freezing
across the area.

&&

Long term...(wednesday night through tuesday)
issued at 312 PM EST Tuesday Nov 25 2014

Long wave pattern to transition to more of a zonal flow through the
period with embedded short waves helping create a roller coaster
pattern with respect to temperatures through the period. No
significant synoptic type snowfall expected in the long term but
some accumulating lake effect snow expected on Thanksgiving.

Fast moving clipper system to pass by to our south Wednesday night.
Models have trended further south and thus have removed the slight
chance of light snow that was in our far southwest with only some
flurries possible. Low level flow will gradually become northerly as
this wave passes through the Ohio Valley. This will allow a weak surface
trough/cold front to move south across the area early Thursday
morning. Light snow showers possible with this feature across the
north where some lake enhancement expected to begin with cold air
advection. Delta T values climb into middle and upper teens through the
day and expect scattered snow showers over Michigan counties and Northwest
Indiana near the lake through the day. Secondary trough drops south
in afternoon and passage of this feature should aid in a brief
window of decent lake effect snow from late afternoon into the middle
evening hours. During this period...Delta T values rise into the 20s
but inversion heights not great in the 5-7kft range. Saturated layer
does extend to around 5 or 6kft with partially saturated dgz and
northwest trajectories. This should be sufficient for a few good
bands of lake effect and some accums. Expected amounts currently
look to be in the general 1 to 3 inch range. Duration should be
short and diminishing after 03z as flow quickly backs to southwest
and warm air advection increases ahead of next short wave.

This next short wave and warm air advection to bring at least a
chance for light snow Friday...especially north where deeper
saturation looks most likely. Models vary on amount of saturation
but have kept a low pop going for consistency and given uncertainty.
Another decent warmup will follow for the weekend...though this
really just gets temperatures back to near normal for this time of year but
will feel warm given recent pattern. Beyond the weekend uncertainty
continues with respect to location of baroclinic zone and weak short
waves in zonal flow dictating boundary location and how far we get
into the cold sector and for how long. No significant weather
systems currently seen in the long term period but several weaker
short waves likely keeping cloud cover in place with a few low
chances for light precipitation to small to mention.



&&

Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 635 PM EST Tuesday Nov 25 2014

High pressure building into the area this evening will allow light
westerly winds to become variable overnight. Back edge of stratus
deck currently along weak ridge axis over Illinois but have doubts it
will make much eastward headway overnight as ridge weakens. Light
easterly winds should develop on Wednesday as a weak low pressure
system drops southeast from the northern plains. This should advect low clouds
back to the west so forecast MVFR ceilings to predominate through the
period.

&&

Iwx watches/warnings/advisories...
in...none.
Michigan...none.
Ohio...none.
Lm...Small Craft Advisory until 7 PM EST this evening for lmz043-046.

&&

$$

Update...jt
synopsis...Fisher
short term...Fisher
long term...Fisher
aviation...jt



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