Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 160843

Area Forecast Discussion
National Weather Service Marquette MI
443 AM EDT Mon Jul 16 2018

.SHORT TERM...(Today and tonight)
Issued at 442 AM EDT MON JUL 16 2018

A mid-upper level low moving east through northern Ontario has
propelled a cold front through all but the eastern third of Upper Mi
early this morning. 850 mb moisture transport and MUCAPE values in
excess of 1000 j/kg out have supported scattered t-storms out ahead
of the front over eastern counties early this morning. Radar and
model trends suggest these storms should be exiting Luce County
within the next hour.

Today, expect noticeably cooler and less humid air behind the front
today. Also it will be windier, especially in the afternoon as ample
sunshine and cooler air aloft give way to sufficient mixing in the
afternoon. With west to northwest winds overspreading the area
behind the exiting cold front, these winds will be downsloping into
the south central portions of the forecast area. Expect high temps
to range from the lower to mid 70s nw with onshore flow while lower
to mid 80s will be reached south central due to downslope flow.
Expect nw wind gusts to to reach upwards of 25-30mph, and perhaps
locally a bit higher, with 0-3km lapse rates steepening nicely in
the afternoon. Gusty nw winds could cause a moderate risk for
swimming toward evening for Marquette and Alger county shorelines.

Tonight, dry conditions and mostly clear skies continue tonight in
the wake of the front. Expect min temps from the upper 40s interior
west to mid to upper 50s south central in continued nw downslope

.LONG TERM...(Tuesday through Sunday)
Issued at 439 AM EDT MON JUL 16 2018

Sharp upper level trough over Manitoba and northern Ontario today
loses some of its punch as it crosses Hudson Bay into Quebec on Tue.
Still will have a glancing blow of cooler air tied to the trough
sweep across Upper Michigan on Tue. Coolest temps in the 60s will be
near Lk Superior with gradient north to northwest winds as sfc high
pressure builds from south central Canada to the Upper Great Lakes.
Stronger winds and building waves will likely result in a high swim
risk on Lk Superior for Tue, especially for Alger county. With the
high centered on Upper Michigan Tue night, may see lows in favored
cold spots drop into the upper 30s or lower 40s.

The cool down will not last for a long time though as the exiting
upper trough and sfc ridge will bring warmer return flow to Upper
Michigan starting on Wed. Have highs reaching back into lower 80s
away from lake breezes but humidity values should still be on the
lower side. Based on the chilly night Tue night and sunshine/mixing
on Wed, lowered Td compared to what model blends gave. Seems it will
be the driest in the interior east closer to departing high pressure
ridge. Stronger south winds on Wed night into Thu should result in
much warmer conditions on Wed night then temps warming into the 80s
all areas away from Lk Michigan on Thu. Should stay dry until Late
Thu into Thu night when shortwave trough and associated sfc low
pressure system approaches the Upper Great Lakes from the west.

This late week system now looks to move farther north across
northern WI and Upper Michigan, which will bring good chance of
scattered showers and possible thunderstorms to much of Upper
Michigan especially Fri into Fri night. Since the low only slowly
drifts east of Upper Michigan into the weekend, will have lingering
chances for showers into Sat and Sat night, especially over the east
half. Temps on Fri likely warmest over far east with later arrival
of rain chances. Farther west on Fri with better chances of rain and
thicker clouds, readings should remain in the low to mid 70s. Highs
on Sat should be in the 70s across the board and with better chance
of north winds behind the low pressure system, it could stay in the
60s near Lk Superior. Dwpnts back into the 60s will lead to more
humid conditions Fri and Sat, though at least temperatures will not
be in the 80s or 90s while the dwpnts are higher. System begins to
lose its influence of the weather over Upper Michigan on Sun, but
still have some slight chances for rain. ECMWF slowest departing the
upper system where the GFS and GEM are moving it out of the area by
that time. Based on farther north track of sfc low on Fri, seems
that Fri into Fri evening will be when the better chance of thunder
occurs. Though admittedly a bit early to diagnose, instability and
shear profiles forecast attm do not suggest severe weather is likely
in this setup. Only smaller chances of thunder would occur into Sat
with greater warmth/instability staying well to the southeast closer
to the sfc low.

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 124 AM EDT MON JUL 16 2018

A dry cold front will push eastward across all terminals later
tonight through the morning hours. Expect VFR conditions will
continue with breezy west to northwest winds by Mon afternoon.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 442 AM EDT MON JUL 16 2018

Lingering fog over Lake Superior will dissipate later this morning
as drier air behind the cold front pushes over the lake. North-
northwest winds behind the front could become gusty this afternoon,
but should be less than 30 knots. By Tuesday, high pressure will
start to work in across western Lake Superior, so expect the gustier
winds to be confined across eastern Lake Superior. Later in the
week, high pressure will move across the region bringing light winds
on Wednesday/Thursday.

Upper Michigan...
Lake Superior...
Lake Michigan...
  Dense Fog Advisory until 6 AM EDT early this morning for LMZ248-



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