Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 241959

Area Forecast Discussion
National Weather Service Marquette MI
359 PM EDT WED AUG 24 2016

.SHORT TERM...(This evening through Thursday)
Issued at 358 PM EDT WED AUG 24 2016

12Z raobs/latest wv imagery and RAP analysis show a shrtwv moving
ENEwd thru the Ncentral Great Lks in the SW flow aloft btwn upr rdg
axis over the SE Conus and a closed upr lo moving slowly to the E
into srn Manitoba. The shrtwv caused some showers over mainly the SE
2/3 of Upr MI this mrng...but the pcpn has diminished to isold-sct
showers with the arrival of deep lyr qvector dvgc/subsidence/mid lvl
drying in the wake of the shrtwv now departing to the E. A sfc cold
fnt associated with the distrubance in srn Manitoba/accompanying sfc
lo pres in NW Ontario is drifting into wrn Lk Sup, with much drier
air following this bndry. Some hi clds on the nrn flank of another
shrtwv moving NE toward the Midwest is bringing some hi clds to srn
MN and wrn WI.

Late today/tngt...Expect lingering showers to diminish thru early
this evng as the Great Lks shrtwv continues to the E and mid lvl
drying/subsidence dominates. Although some of the hier res models do
generate some additional showers as the trailing cold fnt crosses
the area this evng, aggressive mid lvl drying/hi stability shown on
RAP fcst sdngs and then loss of daytime heating this evng wl greatly
limit this potential. So tended toward the drier 12Z Cndn model.
Although drier llvl air wl arrive as well overngt, the aprchg hi
clds and a steady WNW h925 flow wl tend to restrict nocturnal
cooling a bit. Expect min temps in the 50s to arnd 60 over the E,
where the drier llvl air wl arrive latest. Locations near Lk Sup wl
be even warmer.

Thu...Shrtwv now over srn Manitoba is progged to move more steadily
to the E but shear out/weaken in the process. Although there is a
period of some dvpa/deep lyr qvector cnvgc fcst in the mrng and a
reinforcing cold fropa, lingering lo/mid lvl dry air warrants a dry
fcst even if some diurnal cu develops. h85 temps peaking near 14C
over the E ahead of this second cold fropa wl allow temps to rise to
near 80. Max temps over the W downwind of Lk Sup wl probably hold in
the 60s with a gusty W wind up to 30 mph off Lk Sup following the
second fropa.

.LONG TERM...(Thursday through Tuesday)
Issued at 503 AM EDT WED AUG 24 2016

Models suggest that a progressive pattern will prevail with a
mid/upper level trough over nrn Ontario Thursday that will slide
into nrn Quebec by Friday as another trough develops over the nrn
Rockies. The upstream trough is expected to move into the nrn plains
Saturday and through the nrn Great Lakes Sunday. Cooler and drier
weather will build into the nrn Great Lakes from Thursday into Friday
as high pressure builds from the nrn plains into the Great Lakes.
Shra/tsra chances return for the weekend as the plains trough moves

Thursday into Friday, Breezy conditions, especially over the
Keweenaw, will prevail with wrly winds gusting to 20-30 mph, as the
dry slot moves over the area. A trailing secondary cold front and
shrtwv could bring some isold -shra into wrn cwa Thursday night into
Friday morning. Even with shallow moisture, mainly below 750 mb, 850
mb temps down to 6C will also support potential for nw flow lake
enhanced pcpn.  Otherwise, cooler air and drier air will prevail
with highs from the upper 60s west to mid 70s south and east and
dewpoints falling into the mid 50s.

Saturday-Sunday, although models trended stronger with the trough
and were in better agreement that it will bring bring good coverage
of shra and a few tsra into the region, model differences remain with
the timing of the trough through the cwa. The GFS/GEFS remained
faster than the ECMWF resulting in enough uncertainty for mainly
chance pops.

Monday-Tuesday, Expect drier conditions with mid level and sfc
ridging building into the area behind the trough Monday. A mainly
zonal pattern will allow potential for another shrtwv to approach
the area by Tuesday. Temps will remain at or slightly above
seasonal averages with highs in the mid to upper 70s.

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 158 PM EDT WED AUG 24 2016

The arrival of drier llvl air wl result in a return of VFR
conditions at all 3 TAF sites by this evng. Expect a gusty W wind up
to 25 kts to develop on Thu under a tightening pres gradient. The
best chc for stronge gusts will be at the more exposed CMX location.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 358 PM EDT WED AUG 24 2016

Expect winds to veer to the W following a cold frontal passage
tonight, with wind speeds over the W half up to 25 to perhaps 30 kts
on Thu. The winds will veer further to the NW on Thu night but then
diminish into Fri with the closer approach of hi pres/flatter pres
gradient. SE winds up to 20 kts will then prevail on Sat night into
Sun between the departing hi pres and a lo pres approaching from the
SW. Following the passage of this lo, light winds under 20 kts will
prdominate later on Sun and Mon with a relatively weak gradient in

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


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