Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Gaylord Michigan
1230 PM EST Tuesday Jan 27 2015

issued at 948 am EST Tuesday Jan 27 2015

Inherited forecast working out as planned. Still some lingering
flurries...especially hugging the Lake Huron coast south of
Alpena. These should come to an end as flow GOES north and dry air
deepens. Otherwise...sunny and seasonable with highs mostly in the


Near term...(today through tonight)
issued at 232 am EST Tuesday Jan 27 2015

High impact weather potential: none.

Regional pattern: can/T help but notice the classic satellite
presentation of rapidly developing cyclone along the East Coast
early this morning...but alas the weather is a good bit quieter in
these parts as northern Michigan continues to be sandwiched between
deepening eastern noam trough and longwave ridging centered along
The Rockies ensuring a continued flow of northwesterly winds aloft.
Band of moisture is pushing across northern Michigan as of this
writing...along eastern flank of broad warm advection regime
centered west of Lake Michigan south of southward dropping low
evident from the surface up to 800 well as a middle level
contribution from southeastward dropping shortwave /seen as a nice
swirl in WV imagery dropping through Michigan/. This moisture and
weak ascent has manifested itself as a broad area of light snow that
has been struggling to overcome llevel dry wedge as it tries to push
across Lake Michigan and into northwest lower. Finally...llevel
easterly flow along western periphery of Canadian high is supporting
lake clouds/-shsn along much of the coast of northeast lower with
t8s around -11c.

Through daybreak: light lake effect snow band extending along the
coast from pzq to slh will continue to fan out as it is pushed south
by backing llevel flow. We continue to see light returns further
south from apn to Harrisville...and expect these to
scattered flurries/light snow will remain in the forecast through
daybreak for the coast of northeast lower. Elsewhere...apx 88d
showing band of -sn making it/S closest approach to northwest lower with
surface observations supporting the idea that the llevel dry wedge
evident in the 00z apx radiosonde observation is holding strong. Expect significant
cloudiness to remain...with some potential clearing reaching
chip/Mack towards daybreak. Temperatures in this area should sneak
into the single digits...with temperatures remaining 10-15 south of the
mighty Mac.

Today: temporary Rex block strengthens along the US East Coast with
classic high over low pattern extending from the surface to middle
levels. This will continue to bring weakening to surface system
west of the lakes that will pretty much wash away today. With this
occurring and overhead shortwave energy passing south and east of
the region...threat for synoptic snows will be over. More
complicated will be llevel moisture evolution...with current
southeasterly flow slowly backing northeasterly as downstream high
pressure builds west. This should allow a slow erosion from east to
west of deep moisture with increasing sun resulting. Exception will
again likely be along the coast of Lake Huron...with some
clouds/flurries probably continuing through the morning south of apn
over northeast lower. By the flow loses its easterly
component...clearing should pretty much reach all locations. T9s
near -12c suggest low 20s for temperatures...right in line with
guidance consensus.

Tonight: potential definitely there for a cold night with western
edge of surface ridge axis pretty much right overhead by
evening...sinking south and allowing flow to back southwesterly
after midnight. Never a guarantee given cloud concerns...and with
backing flow...focus turns to Lake Michigan and llevel temperatures
that...despite warming...should be cold enough to allow for some
cloud development. At the same time...first high clouds ahead of
next weather system look to arrive as warm advection aloft commences
after midnight. Thus...confidence in cold temperatures greatest away from
the coast of northwest lower /where cloud concerns are greatest/ and
eastern upper...where developing southwesterly gradient is strongest
here /h1000 geostrophic winds 15-20kts/ threatening to keep the
llevels mixed. Outside of these areas...temperatures will likely fall to
or below zero again...with the coldest spots potentially reaching
-5f or so. Temperatures 10-15 immediate coast of northwest lower...and single
digits above zero for eastern upper.


Short term...(wednesday through Thursday night)
issued at 232 am EST Tuesday Jan 27 2015

Pattern description and evolution:

A general ridge west and trough east patter looks to hold for
awhile. Longwave troughing over the Pacific/Alaska will continue to
send shortwaves into western Canada...set to drive toward northern
Michigan. The next wave/clipper is fairly decent...already into
British Columbia...and with precipitable waters near a respectable 0.75". There is
also a cut off low spinning over California...underneath the overall
ridging. This feature is expected to lift out of The Rockies and
into the northern plains...possibly working in tandem with the main

Associated weather:

Back door drying from NE flow early on Wednesday will rapidly turn
cloudy with the approach of deep warm air advection...pocket of upper divergence
and overall respectable and strengthening deep layer -divq. These
are the result of merging/near merging two waves...which may also
lead to a band of enhanced forcing due to frontogenesis. Right
now...the strongest forcing and deep moisture is expected across
eastern upper. Am concerned to some degree of the lack of deep
moisture Gulf...and much of the forcing likely being
used up to saturate the atmosphere. However...those precipitable waters and
presence of both waves could bring a good 2-4" across northern Michigan.
Do not see any lake help with lake surface t's 1-3c and 800 mb temperatures rising
toward 0c to -2c when snows are expected to develop. The initial
snows are seen across eastern upper with the elevated warm front and
potential developing fgen...for Wednesday afternoon. The best snows
will fall Wednesday night into Thursday morning...before forcing
wanes and deep drying ensues. Strong cold advection develops later
Thursday afternoon and mainly Thursday night...with 800 mb temperatures falling
to -16c to -20c....and light lake effect snows likely. Gusty northwest
winds will make things feel quite chilly with wind chills falling
below zero.


Long term...(friday through monday)
issued at 232 am EST Tuesday Jan 27 2015

A few changes. Very chilly air and light lake effect continues
Friday while a weak clipper and elevated warm front try and work on
lingering...yet loosening baroclinic zone. No impressed with this
feature...and may just be dealing with some remnant lake effect
flurries. Of more note...another California trough underneath the
persistent ridging may eject into the plains while developing low
pressure in Texas Saturday. We could actually see a system tap
deeper moisture from the Gulf...and move up our way Sunday/early
next work week. Will have to keep an eye on this over the coming
days. Maybe a better snow?


Aviation...(for the 18z tafs through 18z Wednesday afternoon)
issued at 1226 PM EST Tuesday Jan 27 2015

VFR conditions. Clear skies gives way to slowly increasing high
clouds tonight well ahead of next clipper system. Winds remain
light. Some hints of Lake Michigan produced MVFR strato-cumulus
developing across kpln/ktvc/kmbl Wednesday morning. Will not go
this Route just yet.


Apx watches/warnings/advisories...


near term...Arnott
short term...smd
long term...smd

National Weather Service Glossary of Abbreviations