Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 170420
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
1220 AM EDT Tue Oct 17 2017

.SHORT TERM...(This evening through Tuesday)
Issued at 336 PM EDT MON OCT 16 2017

...Quiet weather with warming trend...

Still lingering cool temps aloft this aftn, but with ample sunshine
temps have reached the low to mid 50s. Southwest low-level flow off
with the cold temps aloft has resutled in enough over water
instability for lake effect clouds and a few rain showers along the
eastern shore of Lk Superior and over far eastern Upper Michigan. A
few mid clouds spilling in from the northwest and just a few cu but
otherwise skies over Upper Michigan are mostly sunny. Has been
breezy at times on the Keweenaw due to more exposure to the westerly
flow. After some lingering mid clouds early this evening skies
should be clear most of the night into Tuesday. Temps should be
warmer than last night as warm front crossing the region keeps winds
up just enough to prevent decoupling. Even so the interior areas may
dip into the upper 30s. Warming temps aloft and plenty of sunshine
on Tue will lead to temps into the 60s most areas with upper 60s for
parts of west half. Coolest temps will be near Lk Michigan and over
the far east where there will be more cloud cover.

.LONG TERM...(Tuesday night through Monday)
Issued at 250 PM EDT MON OCT 16 2017

...Warm with next chances for rain arriving next weekend...

Upper level troughing over the area early this week gives way to a
more zonal flow pattern mid to late this week. Upper level trough
slides across northern Ontario late Wed into Wed night. Main 980mb
sfc low stays well to the north over Hudson Bay but weak cold front
should bring slightly cooler temps on Thu, especially near Lk
Superior with onshore winds. Main impact from this front will be
gusty winds, both ahead of it on Wed when gusts could reach 30-40
mph but also in its wake on Thu when northwest wind gusts could
reach at least 30 mph if not higher.

Once the shortwave trough exits into eastern Canada by Fri and Sat,
heights will rise sharply downstream of developing troughing over
western Conus. Low pressure tied to that troughing moves from
western Canada Sat to scntrl Canada on Sat. Upper Great Lakes will
be within low-level southwesterly flow ahead of the low. H85 temps
are forecast to reach low-mid teens Fri into Sat. Conservative
estimates would put high temps into the low 70s both days. Given the
setup with limited cloud cover in the warm sector could see isolated
readings pushing 80 degrees on Friday. More cloud cover Sat,
especially west will keep that potential more limited but still we
are looking at temps that would be solid 15-20F above normal both
days.

Chances for showers and possible thunderstorms will increase through
Sat and especially be higher Sat night into Sun morning as surge of
very high or possibly record breaking PWATS advects into the region
ahead of approaching sfc cold front. NAEFS ensembles indicate PWATS
up to 2 SD above normal, but based on current medium range guidance
could see those deviations increasing further as we get closer to
the weekend. Despite similar setup to this past weekend in terms of
a wetter pattern as the weekend goes on, the lack of strong low
pressure/tighter pressure gradient in the vcnty will result in winds
not near as strong as was just experienced this last weekend.

Once the cold front moves through, looks like upper level pattern
will try to switch to something that would bring a more typical fall
like weather pattern to the Great Lakes. Also it appears that this
troughing would be more persistent per current models and NAEFS and
EMCWF ensembles. At the least, max temps for much of next week would
have better chance of ending up blo normal (normal highs center
around 50F for last week of Oct across Upper Michigan). Given the
way fall has gone thus far, we`ll have to see if these trends hold
up.
&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1220 AM EDT TUE OCT 17 2017

A dry air mass will dominate thru tonight, ensuring VFR conditions
continue at KIWD/KCMX/KSAW thru this fcst period. With low-level jet
currently over the area shifting e overnight, ongoing LLWS will end
from w to e before daybreak.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 336 PM EDT MON OCT 16 2017

Expect southwest winds to increase to 20-30 kts tonight before
diminishing to 20 kts or less Tue/Tue night. Another period of
stronger southwest winds of 20-30 kts is expected Wed into Wed
evening with west winds 20-30 kts later Wed night into Thu. Could be
close to gales on Thu, but right now looks to stay just below. South
winds should stay mainly 20 kts or less Fri into Sat ahead of next
cold front that moves through late in the weekend.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&

$$

SHORT TERM...JLA
LONG TERM...JLA
AVIATION...Rolfson
MARINE...JLA


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