Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 120327

Area Forecast Discussion
National Weather Service Gaylord MI
1127 PM EDT Sun Mar 11 2018

Issued at 856 PM EDT Sun Mar 11 2018

Lead shortwave trough and developing surface reflection expected
to dive into our area overnight. Already a band of very light snow
tied to this mid level impulse just to our northwest, with this snow
expected to increase some in both organization and intensity as it
pushes into western sections of the area within the next few hours.
This band of snow will continue to slide east, likely reversing
organizational trends as it pushes into downslope regions of
northeast lower Michigan during the morning. Quick movement of
system, combined with precipitable water values at or slightly above
a quarter of an inch and omega pegged well aloft and above the
favored dendritic growth region should keep snowfall amounts in
check. Latest guidance trends fully support that which was
inherited, with snowfall totals averaging one to perhaps 3 inches by
later Monday afternoon, with those highest totals in the northwest
half of the area. No headlines needed.


.NEAR TERM...(Tonight through Monday)
Issued at 312 PM EDT Sun Mar 11 2018

High Impact Weather Potential...snow returns late tonight and Monday.

A ridge of high pressure extends east into MI, separating low
pressure systems in the TN Valley and along the south shore of
Hudson Bay. That northern low is associated with a potent shortwave
diving south from the arctic, and a closed 500mb low will be just
north of the Sault by late Monday. An brief spike in warm advection
ahead of this system will contribute to some light synoptic snow
late tonight and Monday morning. Emerging lake effect snow is
expected Monday afternoon in strengthening cold advection. Snow
trends are the main concern.

Quiet out there now, with a considerable cu/stratocu field
near/north of M-32, and less so to the south. Swath of layered
clouds and very light precip is to our w and nw, across MN/nw WI/far
western Superior. Forcing within this area of enhanced moisture will
increase markedly tonight as the vigorous arctic shortwave dives
south. However, moisture is not particularly abundant (to be
expected with a system originating from the Canadian arctic). We
should see only a relatively narrow tongue of light snow migrate nw
to se across northern MI late tonight and Monday morning. Leading
edge of snow will edge into western Chip/Mack Cos toward midnight,
Sault/PLN/TVC/MBL toward 3 am, and Rogers/W Branch toward
daybreak. (By then, snow will be waning in western Chip/Mack and
west of TVC). Synoptic snow will tend to diminish Monday morning.
However, as 850mb temps diminish into the lower minus teens by
afternoon, some snow showers will redevelop in nw lower/eastern
upper MI (NNW flow), even as the synoptic precip component further
minors out in ne lower.

Snow totals for tonight/Monday will be 2-3" in eastern upper MI,
and 1-3" in northern lower (highest just e and se of Gd Trav Bay,
lowest near Saginaw Bay). This is not worthy of an advisory, though
any adjustment toward more snow would change that.

Min temps tonight near 20f to the mid 20s. Max temps Monday low to
mid 30s.


.SHORT TERM...(Monday night through Wednesday)
Issued at 312 PM EDT Sun Mar 11 2018

...Lake Effect Snow Showers...

Primary Forecast Concern...Snowfall accumulations.

An upper level trough along with embedded short waves takes its time
meandering across northern Michigan through Tuesday night.
Meanwhile, over lake instability slowly increases (but only into the
modest range) as 850 mb temperatures gradually fall off from about
-12 C at 00z Tue to -15C at 00z Wed. The flow veers from north
northwest Monday evening to northerly overnight Monday into Tuesday
before backing back into the north northwest Tuesday evening. Model
soundings still look fairly impressive with inversion heights
topping of at about 7,000 feet in most cases. At this juncture, am
not expecting huge snowfall amounts due to the limited over lake
instability but favored targeted areas (mainly near the Lake
Michigan lake shores) could see a few inches in total. This may be
handled by winter weather advisories (if even necessary) but best
course of action at this point seems to be to wait to see how it all
evolves. Activity should fall apart early Wednesday with pronounced
surface and upper level ridging. Temperatures will average a few
degrees below normal for mid March.

.LONG TERM...(Wednesday night through Sunday)
Issued at 312 PM EDT Sun Mar 11 2018

Long term forecast begins with a departing low pressure system to
our east providing some lingering moisture and cold enough 850mb
temperatures to perhaps produce some lake effect flurries/light snow
over eastern upper and possibly parts of northern lower through the
first half of Thursday. After this time period confidence is really
low as long range models are differing has an
amplified ridge over the midwestern United States, pushing
aforementioned moisture associated with the departing low pressure
system eastward and replaced with much drier air, while the other
model has a much weaker ridge that allows moisture and colder
northwesterly flow to continue filtering in producing lake effect
clouds/light snow through the beginning of the weekend. The
uncertainty continues into the one model has high
pressure building into the Great Lakes region providing rather quiet
weather, while the other has a cold front associated with a low
pressure system over northeastern Ontario dragging through the
forecast area Friday night through Saturday morning providing a
quick shot of some minor accumulating snow. This is definitely going
to be a changing forecast through the upcoming days. Highs will be
in the mid 30s to mid 40s, while low temperatures will be in the
upper teens to mid 20s.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1123 PM EDT Sun Mar 11 2018

Band of IFR producing snow and lower cigs expected to develop and
move west to east across the taf locations this morning. Snowfall
totals look to remain light, on the order of an inch or two. Snow
to liquid ratios will be decreasing with time as temperatures
warm, which should help negate any blowing snow concerns, despite
increasingly gust northwest to north winds. Snow expected to
become much more scattered this afternoon and evening, with the
greatest threat for more organized activity spreading to the
western taf locations of KTVC and KMBL. Latest trends support
minimal additional accumulations. Cigs are expected to lower a bit
area wide this evening, but look to remain above IFR threshold.




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