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National Weather Service Gaylord Michigan
600 PM EST Friday Feb 27 2015

Near term...(this evening through tonight)
issued at 403 PM EST Friday Feb 27 2015

Sure sign #1 of our (painfully) slow March to Spring in northern
Michigan - diurnally-driven cumulus clouds! Next on the list is our
First Lake breeze...which typically does occur this time of year but
has not just yet. Time to be patient. In the meantime...really not a
bad day out there...minus the continued cold conditions...though
late afternoon readings today are roughly 7-10 degrees above those
from yesterday...courtesy of the beginnings of return flow aloft and
slightly deeper mixing with high pressure marching to our south
along the I-80 corridor. As alluded to is nice to see
some diurnal cumulus development...being fed by a lake moisture component
off open water generally south of Leelanau County but fueled farther
inland via surface "heating" from our ever-increasing sun angle. A
little surprised we haven't seen a bit more flurry activity but then
again our ambient airmass remains quite dry so it's not completely
without explanation.

Looking for another quiet night tonight...but with some big
questions regarding overnight lows. For most should not
(hopefully!) Be as cold as recent we see high pressure
working into Pennsylvania setting up a much better gradient up this
way through the night. With that have some concerns about
more sheltered well as southeastern portions of the
area where the gradient looks to remain rather slack for a longer
period of time. Can foresee those spots really tanking the first
part of tonight before steadying out or rising after 2-3am. Areas
closer to Lake Michigan should be protected thanks to a persistent
(albeit light) southwest breeze...which may impact much of eastern
upper as well. All of this of course sounds good on paper...but will
really have to watch the potential for localized boundary layer
decoupling simply given our very cold snow pack and tendency for
many of our sites to do that up this way. Should that
can easily subtract 10 degrees from going lows...though at the
moment that remains a less than likely scenario. In addition...lake
clouds should shrink back toward the Lake Michigan coast
overnight...but may taunt areas near the shore with some flurries.
No matter how it all shakes out...should see many spots near or
below zero once again...only adding to our already impressive tally
of such nights during the month of February.


Short term...(saturday through monday)
issued at 403 PM EST Friday Feb 27 2015

..slowly moderating temperatures/light snow Sunday and Sunday

High impact weather potential: minimal.

Pattern synopsis/forecast: broad long wave trough encompasses North
America this afternoon...with an anomalous -epo ridge (+2 Standard
deviations) over the eastern Pacific jutting up into Alaska. A
split is developing within the western portion of the long wave
trough over the western u... a positive tilt southern branch
wave over California and the Great Basin this weekend...and a
northern branch short wave trough that will swing through the
northern plains/Midwest/Great Lakes in the Sunday/Monday time frame.

Height falls from this northern branch wave will spread across
Michigan starting Saturday night...with the strongest energy looking
to arrive Sunday night/early Monday. This will be followed by short
wave ridging for Monday. At the surface...1040mb high centered over
Iowa/Missouri this afternoon will move into the middle Atlantic/
northeast Saturday...allowing southwest low level flow/warm
advection to commence. Passage of northern branch short wave trough
Sunday night and resultant surface response will swing winds back
around to the northwest Sunday night with a decent push of cold
air to start next week.

Primary forecast concerns: evolution of snow threat Sunday/Sunday
night is the main concern...along with any lingering lake convection
especially with next cold push Monday.

Saturday...weekend starts with a weak short wave trough sliding
across Southern Lower Michigan/northern Indiana and Ohio...but with
a very dry air mass aloft across northern Michigan this feature
expected to have minimal impact this far north. Just the usual
pesky lake cloud issues will be the main problem for Saturday...with
just enough shallow instability in southwest flow off Lake Michigan
to push some clouds/flurries into northwest lower with a bit of a
diurnal expansion very similar to this afternoon. Outside of that
partly to mostly sunny skies expected with temperatures continuing
to creep upward (though still a good 10 degrees below normal). Warm
advection increases Saturday night along with a push of moisture...
though stronger low level inflow will be focused into the Ohio
Valley through Sunday. Looks to be an initial push of snow into
lower Michigan...though much of this initial wave may pass by to the
south. There are indications that what we may see is an uptick in
snow showers off Lake Michigan into northwest lower so will focus
initial snow chances Saturday night into early Sunday in these
areas...with a lesser chance over southeast counties of the forecast

Sunday...synoptic snow evolution on Sunday will likely be tied to
forcing associated with northern branch short wave swinging into
the upper Midwest Saturday afternoon and upper lakes by Sunday
evening. Expect snow coverage to increase ahead of this short wave
trough Sunday afternoon/evening. Prior to this expect southwest
flow snow showers to continue off Lake Michigan and into northwest
lower Sunday morning. Synoptic snow expected to continue through
Sunday evening...then wind down west to east overnight with short
wave passage. May see a quick transition to lake convection with
arrival of thermal trough with short wave passage...with winds
shifting to the northwest. At this point not planning on
significant accumulations Sunday through Sunday inch
or two across northern lower for now.

Monday...deep layer ridging pushing across the Great Lakes on Monday
will lend itself to another quiescent day...though some flurries
off Lake Michigan can be ruled out.


Long term...(monday night through friday)
issued at 403 PM EST Friday Feb 27 2015

High impact weather potential: accumulating snow possible Tuesday
afternoon into Wednesday.

The main focus in the extended will be early in the period as a
strong 160+ knots upper level jet stream noses into the Great Lakes
Monday night into Tuesday along with the beginnings of an
approaching system taking shape to our southwest. A fairly
substantial modification to our local airmass looks to be on the tightest baroclinic zone slides northward into the S.
Mi/N. IL/N. In during the day Tuesday. In fact... so much of a
modification that 800 mb temperatures may approach 0c across southern parts of
the County Warning Area by Tuesday evening! As it sits now...low pressure (able to
tap into Gulf moisture - ever so elusive this winter in northern
michigan) is expected to ride along this boundary by midweek...
bringing a swath of snow to the region during the Tuesday afternoon -
early Wednesday morning timeframe. Of course with several days to go
before the event unfolds...timing and exact placement of the low are
yet to be nailed down and will ultimately be the determining factors
as to the whether or not part of the County Warning Area experiences a decent snow
event. So far run-to-run consistency is on our side that a
widespread synoptic system will impact the area...but keep in mind
the other side of the Coin that several systems of similar nature
over the past two-three months have ultimately remain suppressed to
our south.

The modified 800 mb temperatures discussed earlier do not look to stick around
long as another shot (albeit brief) of Arctic air is set to spill
into the region Thursday before signals point for another bout of
more "mild" weather to return just in time for next weekend.


Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 600 PM EST Friday Feb 27 2015

Strong high pressure center will slide south of Michigan tonight...
reaching New England by Saturday night. Much of northern lower Michigan
will remain VFR through Saturday...except locations south of a line
from tvc to htl where MVFR lake clouds will gradually spread into
that region under the direction of west/SW low level flow. SW surface
winds will remain around or below 10 kts through the forecast period.


Apx watches/warnings/advisories...


Near term...Lawrence
short term...jpb
long term...gillen

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