Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 201156

Area Forecast Discussion
National Weather Service Marquette MI
756 AM EDT Tue Jun 20 2017

.SHORT TERM...(Today and tonight)
Issued at 416 AM EDT TUE JUN 20 2017

Upper troughing firmly in place from Hudson Bay to the Great Lakes.
More vigorous shortwave is digging across Minnesota within the
western edge of mean troughing. Main sfc low well to the northeast
of the region over northern Quebec at 996mb but there is weaker sfc
trough just northwest of Lk Superior. Are even seeing a few light
showers ahead of these features working west to east across central
forecast area. 00z sounding at CWPL in northern Ontario showed
increasing h7-h5 moisture beneath the upper trough in wake of the
sfc front so plan is to see increasing showers around daybreak
sliding across mainly northwest to central Upper Michigan. Similar
to Mon, would expect most showers to shift to south central Upper
Michigan by mid aftn. Just a small chance of a thunderstorm with
mlcapes up to 300 j/kg but with similar thermal setup to Mon there
could be more instances of cold air funnels. Not enough confidence
though to issue SPS. Will have to be nowcast type issue as it was
on Monday. H85 temps late this aftn change little compared to
Mon aftn so went with high temps mainly in the 60s, coolest near
Lk Superior east of Marquette and warmest over far scntrl where
readings could again near 70 degrees.

Once shortwave over Minnesota slides south and east of the area by
late this aftn, subsidence and strong drying will end any showers by
early this evening and clouds should decrease quickly from west to
east with skies becoming mostly clear overnight. With high pressure
over the plains settling over the western Great Lakes leading to
light winds/clear skies seems that favored cool spots may try to
fall into the lower 40s as is occurring this morning in the vcnty of
the high over south central Canada.

.LONG TERM...(Wednesday through Monday)
Issued at 348 AM EDT TUE JUN 20 2017

Nam shows a 500 mb ridge over the desert sw with troughing in the
ern U.S. and a broad 500 mb trough across the pacific nw and
northern Rockies 12z Wed. A closed 500 mb low will develop over
central Saskatchewan 00z Thu and this will head east into western
Ontario 12z Fri. Nam brings in some 850-500 mb q-vector convergence
and deeper moisture Wed night. Did not make too many changes to the
going forecast for temperatures or weather.

In the extended, GFS and ECMWF show a flattened 500 mb ridge across
most of the southern half of the U.S. 12z Fri with a broad trough
over the northern half and across most of Canada. The broad 500 mb
trough becomes more amplified on Sun over the upper Great Lakes
region and the area stays in upper level troughing into Tue. This
will mean unsettled weather will continue along with below normal

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 755 AM EDT TUE JUN 20 2017

A weak low pressure trough dropping across Lk Superior and Upper
Michigan will result in more showers today. Best chances for rain
will be at IWD and CMX through late morning and at SAW into mid
afternoon. Even with the clouds and showers, conditions should stay
VFR at IWD and MVFR at SAW. Different story at CMX where LIFR
conditions (LIFR cigs and IFR vsby) have already set up this
morning. Low conditions will improve to MVFR-VFR but it will take
until early to mid aftn. High pressure builds in behind the trough
by late aftn and result will be clear skies at all TAF sites tonight
into Wed.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 416 AM EDT TUE JUN 20 2017

A few westerly gusts to 25 kts are possible this morning over the
east half of Lk Superior. Otherwise expect winds to remain 20 kts
or less into Wed. S winds shifting to the SW may reach up to 25
kts late Wed night through Thu night as a low pressure system and
cold front cross the Upper Great Lakes. Winds will diminish below
20 kts Fri into Sat behind the cold front.

Issued at 416 AM EDT TUE JUN 20 2017

The Sturgeon River at Nahma Junction in Delta county is slowly
falling but remains just above action/bankful stage early this
morning. Flood advisory was already extended through later this
morning and will keep that going until later obseravation/trends
suggest otherwise.

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


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