FXUS63 KMQT 180459

Area Forecast Discussion
National Weather Service Marquette MI
1159 PM EST Sun Feb 17 2019

.SHORT TERM...(This evening through Monday)
Issued at 404 PM EST SUN FEB 17 2019

Fluffy lake effect continues. WV loop and 12z RAOBS show a wsw flow
aloft across the Upper Great Lakes with main shortwave trough
sliding across IA, MN and southern WI. Light snow/flurries on north
side of the weakening system have grazed southern Upper Michigan

noteable snow showers today have occurred near Lk Superior,
especially over Marquette county. MQT VWP showed nne winds through
4.5kft most of the day, so there were waves of light to moderate
snow all day across north central. Earlier eye was on mesolow that
formed over eastern Lk Superior possibly on edge of ice shelf near
Michipicoten Island, though tough to tell for sure. In any case, ne
low-level winds out of the persistent high pressure ridge from
northern Canada to the Upper Great Lakes pushed this mesolow
steadily to the sw through the day. The mesolow and enhanced snow
pushed into Marquette county around 2 PM this aftn. Enhanced forcing
from the mesolow as well as NE winds adding upslope and very high
SLRs combined to produce brief, but intense burst of snow with
snowfall rates likely over 2 inches per hour. Widespread heavy snow
with 30-35 dbz echoes have settled down in last hour or so.
Otherwise, lake effect near Lk Superior has been light for most part
with just some light snow showers and flurries over far western
Upper Michigan vcnty of Ironwood to across the Keweenaw.

Tonight into Monday, even though system to the south slides to the
lower Great Lakes, do not expect much change in current setup across
Upper Michigan. Still will have high pressure ridge to the north
keeping ne winds across Lk Superior and Upper Michigan and shallow
low-level moisture to H85/4kft AGL. All that moisture remains within
the DGZ so SLRs will stay around 30:1 leading to at least a few more
inches of fluffy snow. NNW winds may gust 15-20 mph near the shore
late tonight eastern Marquette county into western Alger county, so
could see some patchy blowing snow near Lk Superior. The ne low-
level winds should keep partly to mostly cloudy skies over much of
the area tonight, but inland areas near WI border and over far east
could see temps drop down to around zero if not blo. High builds
more overhead on Monday which will turn winds from ne to nnw, so
expect main focus for snow showers from Marquette to the east toward
Grand Marais and Newberry. Still decent open water over eastern Lk
Superior and with temps at top of inversion around -18c, over water
instability will remain sufficient, though inversion only as high as
H9/3kft will keep the LES on the light side. High temps cool down
further on Mon across Upper Michigan with low teens near Lk Superior
and near 20F far scntrl.

.LONG TERM...(Monday night through Sunday)
Issued at 435 PM EST SUN FEB 17 2019

Models suggest that mid/upper level ridging from the northeast
Pacific into eastern Alaska and northwest Canada will favor
troughing into the wrn CONUS. Although a trough over Hudson Bay and
northeast Canada will maintain confluent flow and sfc ridging
through early this 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.

Monday night, very light wind fields are expected which along with
the ice cover patterns may again allow for meso-low like bands to
organize over eastern Lake Superior. However, confidence in any
details is low.

Tuesday, with the sfc ridge building toward the southern Great
Lakes, sw low level flow will keep the LES offshore over the north.
Partial sunshine will allow temps to climb into the lower 20s.

Wed, Models were in good agreement with a vigorous shortwave lifting
northeast from the central plains into the western Great Lakes that
could bring snow to the area. Moderate to strong 700-300 mb qvector
conv with this feature and modest moisture inflow should be able to
squeeze out 0.20-0.30 inch pcpn amounts. With snow/water ratio
values in the 15-20/1 range, general 3-5 inch snow amounts are

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-Sun, Models have trended farther southeast with the stronger
shortwave and sfc low moving through the central CONUS. Although the
favored ECMWF/GEM keep Upper Michigan on the fringe of pcpn shield,
cannot rule out a shift close to the region given the prominent se
CONUS ridge and stronger farther west solutions of some
GEFS/GEM ensemble members.

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1158 PM EST SUN FEB 17 2019

NE low-level winds will continue overnight before backing nw today.
The ne winds overnight will favor KSAW for most peristent lake
effect -shsn/MVFR conditions. Not out of the question that some
brief periods of IFR vis will occur as well. As winds back today,
-shsn will end, and MVFR cigs should scatter out in the aftn. At
KIWD, expect some lake effect -shsn with MVFR conditions prevailing
overnight. The MVFR cigs may scatter out at times. As winds back
today, MVFR cigs will clear out in the aftn. At KCMX, winds will
continue to be off the lake thru the period. However, with
considerable ice around and upwind of the Keweenaw, lake
effect clouds will likely vary btwn sct and bkn MVFR.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 404 PM EST SUN FEB 17 2019

Quiet conditions continue with winds 25 kts or less through the
forecast period. Heavy freezing spray will persist through Monday
across the eastern half of Lake Superior.

Upper Michigan...
Lake Superior...
Heavy Freezing Spray Warning until 10 PM EST Monday for

Lake Michigan...


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