Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 200748

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

.SHORT TERM...(This evening through Tuesday)
Issued at 302 PM EDT MON JUN 19 2017

Water vapor imagery and RUC analysis reveals mid-upper level pattern
with a ridge over the western CONUS and broad trough into the
central CONUS including the Great Lakes region. Water vapor imagery
also revealed a series of shortwaves from MN and ND rotating through
the trough axis and into Upper Mi this afternoon. Weak daytime
heating under mostly cloudy skies has led to MLCAPE values of 200-
500 j/kg this afternoon enough to support scattered to numerous
showers mainly central and even some isolated t-storms along the WI
border. Given the fairly weak instability combined with minimal deep
layer shear expect only small hail with stronger storms into early
this evening despite lower freezing levels of 8-9 kft. Cool airmass
in place resulted in a cold air funnel sighting in Forsyth Township
in MQT county shortly after noon EDT so issued a SPS highlighting
potential of cold air funnels through the rest of the afternoon.
High temps have been mainly in the 60s with a few lower 70s readings
over southern MNM county. Look for scattered showers and isolated t-
storms to taper off late evening after sunset with the loss of
diurnal heating.

Tonight into Tuesday...Next best chance for showers and possible t-
storms will occur late tonight, after 09z Tue, as the stronger
shortwave trough over Saskatchewan and Manitoba dives se into the
Upper Great Lakes region. Scattered showers and isolated
thunderstorms (along WI border) will be possible into at least early
afternoon Tue as the shortwave works its way through the region and
MLCAPEs will be fm 100-250 j/kg, highest south central. Confluent
flow and mid-level subsidence/q-vector divergence in the wake of the
shortwave will provide for drying conditions west to east later Tue
afternoon. Despite breaks in the cloud cover Tue afternoon,
especially west half, high temps across area will be mostly in the
60s as models show h85 temps of 5-6c.

.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 00Z TAFS through 00Z Tuesday evening)
Issued at 1157 PM EDT MON JUN 19 2017

Satellite imagery continues to show considerable mid-level clouds
over Lake Superior and moving southeast across the TAF sites this
evening. Expect this cloud cover to persist through the
overnight, but fortunately the bases appear to be at VFR conds or
4-5kft agl. Some guidance indicates CIGs will begin to fall just
prior to daybreak with another weak disturbance bringing a VCSH
possibly to TAF sites mid-morning Tue thru the aftn with CIGs
around 1500-2000ft agl. Confidence is not very high with CIGs aft
10z Tue.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 302 PM EDT MON JUN 19 2017

Winds should remain 20 kts or less into Wed, then may increase up to
25 kts Thu into Fri as a low pressure system and cold front cross
the Upper Great Lakes.

Issued at 302 PM EDT MON JUN 19 2017

Heavy rain of 1.25 to 1.75 inches that occurred over central Upper
Michigan on Sunday pushed the Sturgeon River near Nahma Junction in
Delta County to action/bankfull stage early this morning. Based
on current stage and rising trend along with additional rain from
showers this afternoon, will continue flood advisory through late

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


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