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Area forecast discussion 
National Weather Service Gaylord Michigan
335 am EST Friday Jan 30 2015

Near term...(today through tonight)
issued at 1252 am EST Friday Jan 30 2015


Synoptic pattern and observations:

Early this upper trough over the east an associated
surface low...and strong cold front that is working into the East
Coast. Broad ridging across the West Coast...with a weak cyclonic
circulation buried underneath...seen on latest satellite loops
across far Southern California/Arizona and producing rainfall across the SW
Continental U.S.. in between...across the Mississippi Valley...surface high
pressure and cold resides. In northern Michigan specifically...we still
have a tight pressure gradient with northwest winds gusting 25 to 35 miles per hour
and becoming colder. Strongest winds are over and immediately
downwind of Lake Michigan. Lake effect snows are ongoing with 800 mb
temperatures falling through the teens. The better cyclonic convergence is
becoming more unidirectional...veering more north-northwest with time.
Relatively shallow inversion heights (increasing subsidence) around
4000-4500 feet are likely being offset in part due to good lift
within the dgz/optimal temperatures...resulting in decent snowfall
within the bands. Of course the gusty winds are also periodically
blowing around the snow and helping decrease the visibility. Pretty
wintry and nasty mainly within the lake effect bands and where
appreciable snows fell yesterday. A Winter Weather Advisory is in
effect for the better snowfall and winds...poorer conditions west
and south of gtv Bay. The flow aloft is rather fast...with some
sheared out vorticity stretching down the northwest flow into ND/MN...and a
better wave now entering far northern Saskatchewan/Manitoba. Precipitable waters
upstream are around 0.25".

Temperatures ranged from the single digits for much of eastern the upper teens and lower 20s along M-55.

Synoptic pattern evolution and associated weather:

Cold and gusty north-northwest flow will weaken through the day as a looser
pressure gradient arrives...while core of higher pressure sinks into
the Ohio Valley. It'll be quite chilly to start the day with
temperatures in the single below and above zero for most of the
region...and wind chills 5 to 20 below zero. Not as cold west and
south of gtv Bay due to clouds and lake effect snows...but certainly
the continuation of the snow and gusty winds resulting in
periodically poor driving conditions. Will keep current Winter
Weather Advisory going. As winds continue to weaken into the
afternoon...they will also be backing more west in response to
advancing northern Manitoba/Saskatchewan wave. Decay of moisture flux and
a drying bl...will result in a gradual decay of lake effect. Super
sufficient 925mb instability however will likely lead to at least
flurries into the night...and more scattered/likely snow showers for
the overnight. This would be across a good chunk of northwest lower as the
upstream shortwave...brings a little bit of light snow...enhanced by
the shallow instability. The snows may possibly work into The
Straits/Drummond Island...with low level winds just a shade south of
due west.

Most likely no more than an inch...even across northwest lower with lake

Lows mainly 10-20f with lows tonight difficult with a period of
clearing across NE lower and to a shorter period of time eastern
upper (west flow). Temperatures will be crashing when this occurs.
Can foresee single digits below zero easily attainable in these
areas...with cloudy areas in the teens.


Short term...(saturday through Sunday night)
issued at 335 am EST Friday Jan 30 2015

High impact weather potential: nothing major foreseen through the
weekend. There still appears to be a low end risk for some freezing
drizzle Saturday afternoon and maybe Saturday evening...but the
overall impact looks minor given already snow covered/slushy roads
that will remain that way through the weekend.

A familiar-looking pattern with the parade of northern stream
shortwaves continuing...some dropping toward the area and some
skirting just north. Saturday's iteration will feature a modest wave
passing through Ontario...dragging a trailing cold front through the
area during the afternoon hours. Majority of the upper forcing with
said wave will pass to our north...leaving US hinging our bets on
whatever sort of low level/frontal forcing we can muster for precipitation
chances. Brief but notable intrusion of "warmer" air aloft looks to
work into the region through midday...with a lack of moisture above
800mb and cloud top temperatures warming above -10c at least raising an
Eyebrow toward the potential of a little freezing drizzle. As
mentioned yesterday...the ambient airmass to ME just looks a little
too cool to support any significant freezing drizzle...and even if
it were to occur (most likely south of M-32)...any impact should be
minor given the time of day it would occur (during the daylight
hours). Farther north...weak frontal forcing and deep enough
moisture up to 800mb with cloud temperatures down as low as -15c should be
enough to bring at least a brief round of some light snow showers
for many areas along and just behind the boundary. Accumulation
looks minor but it will likely snow...thus higher probability of precipitation will remain.

We sort of sit in no man's land Saturday evening as colder air just
starts to filter into the region...all while we await upstream
trends to see just how much phasing can get take place over the
plains/middle miss valley. Similar to what occurred Thursday
afternoon...can't completely rule out another period of some light
freezing drizzle with saturation shrinking below 850mb but cold air
advection only slowly kicking into gear. That threat should be gone
no later than 03-06z as some very chilly air works back into the
area as expansive low level ridging from the northern plains into
Ontario kicks our low level flow almost due northerly.

Now...speaking of potential phasing to our south...guidance trends
and simple pattern recognition continue to favor little impact this
far north heading into Sunday. Looking more and more likely that
another northern stream wave working through Ontario will act to
block any northward progress of the stronger wave over the middle miss
valley. Not helping matters will also be the above-mentioned very
strong low level ridging (surface pressures nearing 1044mb to our
west)...also acting as a formidable block to any northward progress
of the surface low that is more likely to skirt through the
Tennessee Valley. Given that scenario...could well end up seeing a
good deal of inland sunshine for Sunday and clear skies Sunday north flow favors clouds and light snow showers near the
lakeshores but potentially some quite cold conditions inland. Shear
magnitude of the cold air (h8 temperatures in the -19c to -23c range) and
very shallow moisture argues for only very light snow accumulation
where lake effect does flake size will be quite small
with the dgz basically at ground level. Some potential is there for
spots to dip below -10f Sunday night provided winds and clouds


Long term...(monday through thursday)
issued at 335 am EST Friday Jan 30 2015

We now return you to normal winter weather (though arguably there is
no such thing as "normal weather" in northern michigan). Broad upper
troughing looks to reside over much of the eastern Continental U.S. Through the
entire work week...reinforced at times by a couple of northwest flow
emanating shortwaves that will drag several cold fronts through the
region. Timing and placement of these features of course remains a
challenge... as it often is in such setups...but a general consensus
would place one wave arriving later Tuesday and another sometime on
Wednesday or Wednesday night. The initial wave does at least peak
some interest given a persistent and decent fgen signal noted for a
few days now so something to watch. Outside of synoptic support...
simple step-down toward much colder conditions once again mandates
daily chances for lake effect snow showers...with temperatures
solidly below normal for the first week of February.


Aviation...(for the 06z tafs through 06z Friday night)
issued at 1252 am EST Friday Jan 30 2015

..light lake effect and blowing snow...

Gusty northwest winds and very cold air continues to rip down and across
Lake Michigan...resulting in periods of light lake effect snows
for mainly tvc and mbl. Some of these snow showers will continue
to affect pln more infrequently over the next several hours. Skies
will remain prevailing MVFR across northwest lower Michigan...but a core
of drier low level air ripping south through eastern upper...will
bring a possible clearing MVFR cloud deck to pln/apn by daybreak.
Feel the need to hang on to MVFR ceilings longer...into the daylight

Gusty winds will settle from west to east from daybreak into the
afternoon. Until then blowing snow will continue to try and keep
visibilities down into mainly MVFR ranges...but certainly some sporadic
IFR visibilities possible through daybreak.

Winds will back this afternoon...coming increasingly out of the
west and light heading through the night. This will shove MVFR
lake clouds and flurries back into much of northwest lower. A disturbance
aloft will arrive overnight...bring a touch of light system
snow...mainly pln/apn. Could see some visibilities come down with
enhanced lake effect for the next set of tafs.


Apx watches/warnings/advisories...
Michigan...Winter Weather Advisory until noon EST today for miz020-025-026-



Near term...smd
short term...Lawrence
long term...Lawrence

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