Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 170500

Area Forecast Discussion
National Weather Service Marquette MI
1200 AM EST Sun Feb 17 2019

.SHORT TERM...(This evening through Sunday)
Issued at 214 PM EST SAT FEB 16 2019

Looks like we`ll remain with quiet weather into Sunday. 12z raobs
and wv satellite loop indicate weak ridge aloft across Upper
Great Lakes this aftn downstream of stronger shortwave trough
heading over the northern Plains. Sfc low pressure trough is just
emerging onto the High Plains with swath of snow over mainly SD
while high pressure ridge extends from northern Canada to the
Upper Great Lakes. N to nnw winds out of the high along with
moisture below 3kft and H9/3kft temps of -14c has been good
enough for persistent lake effect snow showers and flurries over
the east half. Very shallow strato cu has pretty much thinned out
over rest of area with just high clouds streaming across ahead of
plains wave.

Following the sfc-H9 winds going from nnw to ne through the night
and into Sun, expect lingering lake effect flurries over the east
this aftn to diminish then reform late tonight into Sun over ncntrl
and Keweenaw. Other main question is whether there could be very low
clouds and maybe even light fog try to form overnight after this
batch of high clouds departs this evening. Even if temps fall well
blo zero, not sure if there will be enough low-level moisture to get
the low clouds and/or fog to develop. If the fog does develop, could
lead to slippery spots on untreated roads, but just not sure if it
will. Sun morning expect low-level moisture blo H85/4kft to increase
across all of Upper Michigan as the plains system slides by to the
south. With the increasing moisture there will probably be some
flurries develop as well. Better chance for light accumulating
snow showers (still 1-2 inches at most) will be over ncntrl near
Lk Superior with some help off the lake. Highs on Sun should be
slightly cooler than today, reaching the upper teens to near 20F.

.LONG TERM...(Sunday night through Saturday)
Issued at 404 PM EST SAT FEB 16 2019

Models suggest that mid/upper level ridging from the Gulf of Alaska
into northwest Canada will persist into much of next week favoring
troughing into the wrn CONUS. Although a trough over Hudson Bay and
northeast Canada will maintain confluent flow and sfc ridging
through early next week, by the middle and end of the week, it will
shift off to the east allowing sw flow through the wrn Great Lakes
and a more active pattern for Upper Michigan.

Sunday night into Monday, a shortwave trough will shift through
far nrn Ontario with the sfc high moving through the nrn plains
allowing colder air to move into the area on nrly winds which will
produce light LES over north central Upper Michigan. With 850 mb
temps around -17C, the DGZ through the shallow convective cloud
layer (equilibrium heights around 4k ft), very fluffy snow
accumulations of an inch or two may be possible. Highs on Monday
will only climb to around 15F north and west to around 20 south.

Monday night through Tuesday, a shortwave sliding through nrn
Ontario shrtwv will bring a wind shift to the west or northwest with
850 mb temps around -18C. There may be a brief period with more
favorable deep moisture. However, overall LES amounts should remain
light with disorganized low level winds.

Wed, Models were in slightly better agreement with a shortwave and
sfc low moving into the western Great Lakes that could bring snow to
the area. Although confidence in any details is still low, moderate
dynamics and isentropic ascent, particularly with the stronger
ECMWF, the potential for light to moderate accumulations.

Thu-Fri, After some light LES in the wake of the Wed system, mid
level and sfc ridging will bring drier weather late Thu into Fri.

Sat, a strong shrtwv is likely to emerge from the sw CONUS. The
models were in better agreement that it could lift into the western
Great Lakes accompanied by a quickly deepening sfc low. Although
high impacts may be possible with this system, confidence in any
details remains low.

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1200 AM EST SUN FEB 17 2019

As high pres ridging strengthens just n of the area, low-level ne
winds will prevail thru today. As a result, expect lake effect
clouds/MVFR cigs/flurries and occasionally -shsn to be the rule at
KSAW thru the fcst period. At KCMX, VFR conditions will likely
prevail thru the night. Later this morning, winds may take on enough
of an easterly component for MVFR cigs/flurries to develop and
linger into mid or late aftn. At KIWD, VFR conditions will likely
prevail into the aftn. NE winds aren`t really favorable for lake
effect clouds/MVFR cigs at KIWD, but there are some indications that
MVFR cigs may develop at that terminal this evening.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 214 PM EST SAT FEB 16 2019

Quiet conditions continue. Expect winds 25 kts or less through the
forecast period. Could be some heavy freezing spray return Sun night
into Mon.

Upper Michigan...
Lake Superior...
Lake Michigan...


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