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Area forecast discussion 
National Weather Service northern Indiana
851 PM EST Thursday Mar 5 2015

Synopsis...
issued at 851 PM EST Thursday Mar 5 2015

Mostly clear skies will continue into the overnight hours. Extremely
cold overnight lows will drop to zero to 5 below zero. Wind chill
values are expected to drop to as low as -10 degrees overnight. High
temperatures on Friday will be in the middle to upper 20s.

&&

Short term...(this evening through friday)
issued at 414 PM EST Thursday Mar 5 2015

Rapid eastward exodus of positive tilted middle tropospheric trough through lower
Great Lakes into eastern states followed by lesser amplitude troffing into
western Great Lakes Friday to solidify dry cp Arctic airmass across region
overnight into early Friday. Increases wrly flow upwind of Lake Michigan to
afford dry air entrainment with any lingering flurries succumbing
to demise near sunset followed by rapid longwave radiational
losses. As surface Ridgeline settles into Ohio Valley on Friday and two high
belted clipper systems track well N-NW...one into far southern Hudson
Bay/northern James Bay the other to Lake Winnipeg by 00 UTC Sat.
Extreme dry upstream air mass characterized by 20 percent of
normal precipitable water...lte 0.10 inches throughout Upper/Middle MS valley. Strong
warm air advection surface-925mb along with high early March sun angle/insolation
with near 10c/12 hour rises at 925mb by 21c in southwestern County Warning Area. As such
have gone a bit hir with temperatures tmrw...strong diurnal plus...muted
on eastern County Warning Area along trailing periphery of exiting cold pool.

&&

Long term...(friday night through thursday)
issued at 414 PM EST Thursday Mar 5 2015

The start of the warmup begins during the day Saturday. Do not
expect much of a maximum temperature difference between Saturday and Sunday
as most of the energy will be used to melt snow.
Additionally...another weak shortwave slips across the Great
Lakes during the day Sunday and this will act to temper the warm
up.

The biggest change in temperatures will occur midweek into the
latter part of the extended forecast. Given the frost depth snow
melt will create isolated flooding in low lying area and poor
drainage locations. Will need to closely monitor waterways for
ice jams as the rivers begin to shed ice and flows increase.

No precipitation during the warm-up and thus little contribution
to the water/flow.

&&

Aviation...(for the 00z tafs through 00z Friday evening)
issued at 624 PM EST Thursday Mar 5 2015

High pressure ridge over Illinois will move east across northern Indiana
tonight resulting in VFR conditions with clearing skies and
diminishing winds. Ridge will move east of the area Friday as a
trough moves into the western Great Lakes resulting in increasing southwesterly winds
and possibly MVFR ceilings toward evening.

&&

Iwx watches/warnings/advisories...
in...none.
Michigan...none.
Ohio...none.
Lm...none.
&&

$$

Synopsis...Murphy/Bentley/rehbein
short term...Murphy
long term...Lewis
aviation...jt



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