Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 260424

Area Forecast Discussion
National Weather Service Marquette MI
1224 AM EDT FRI AUG 26 2016

.SHORT TERM...(This evening through Friday)
Issued at 335 PM EDT THU AUG 25 2016

A shortwave just N of the MN arrowhead is producing some isolated
showers over the arrowhead and even some lightning directly beneath
the shortwave. That shortwave will slide N of Lake Superior into
this evening, but no precip is expected over the CWA. A trailing SFC
trough/cold front will move into the area from the NW late tonight
into Fri, bringing potential for lake enhanced showers over the W
and N central, along with cloud cover. Showers should clear up in
the late morning and afternoon and cloud cover will diminish in
the afternoon and evening.

.LONG TERM...(Friday night through Thursday)
Issued at 315 PM EDT THU AUG 25 2016

Recent model runs have trended faster at brining a return of deeper
mstr/pcpn to the area late Fri ngt/Sat ahead of a shrtwv aprchg thru
MN on Sat. With this faster trend, Sun now looks to be the drier day
of the upcoming weekend. A WNW flow aloft to the E of a bldg upr rdg
in the Plains will dominate the wx pattern next week. A disturbance
embedded in this flow wl track fm Scentral Canada into Quebec early
next week and drag a cool fnt across the cwa Mon ngt/early Tue. More
sgnft extended model differences are then the rule the second half
of next week.

Fri ngt...Although the night wl start off on the tranquil side with
sfc hi pres rdg/mid lvl dry air in place, a SW flow aloft ahead of
an aprchg shrtwv in the Nrn Plains is fcst to draw more moisture
into the Upper Lks later at ngt. The result wl be incrsg clds, and
perhaps some showers near the WI border toward 12Z.

Sat/Sat ngt...Arrival of dpva/isentropic ascent on the 305K sfc/deep
lyr qvector cnvgc/deep mstr ahead of aprchg shrtwv wl cause an area
of more nmrs/wdsprd showers to move into the Upper Lks. There are
still some inconsistencies among the guidance on the strength/track
of accompanying sfc lo pres and location of greater qpf, so tended
toward a consensus of the guidance. While there are differences on
the track/qpf, models have overall trended toward a faster solution.
So tended to bring pops in faster on Sat and then dry out the fcst
quicker on Sat ngt. Plenty of clds on Sat and h85 temps not far fm
12C to the N of sfc warm fnt wl greatly hold down max temps on Sat.

Sun...There could be some lingering mrng lo clds, but arrival of
dnva/deep lyr qvector dvgc/larger scale drying/sfc hi pres during
daytime warming ahead of trailing shrtwv rdg wl bring a return of
some sunshine during the day. H85 temps in the 12-14C range wl allow
for max temps into the 75-80 range away fm some cooling downwind of
mainly Lk Sup with WNW h925 winds. The hiest temps wl be over the
Scentral, where this WNW flow wl downslope.

Early next week...The medium/extended range guidance advertises a
WNW flow aloft over the Great Lks to the E of a bldg upr rdg in the
Plains wl dominate the wx pattern. There is decent agreement a
shrtwv/sfc lo wl tracking thru Scentral Canada on Mon will drift
across nrn Ontario and into Quebec on Mon ngt/Tue. Although there
could be some showers/TS as early as Sun ngt in the WAA ahead of
this feature and as the attendant cold fnt drifts thru the Upr Lks
on late Mon/early Tue, passage of the stronger dynamic forcing to
the N should limit pops over Upr MI. Temps early next week should
average aoa normal.

Extended...Although the longer range guidance points toward a bldg
mean upr rdg in the Plains, there are some sgnft differences among
the explicit longe range models on how far to the S a Canadian hi
pres wl settle in the more or less NW wind component to the E of the
upr rdg axis. While the 00Z ECMWF showed a hier amplitude trof over
ern Canada/a sharper NW flow into the Great Lks/farther S track of
the sfc hi pres into NW Ontario late in the week, recent GFS runs
indicate a more WNW flow wl prevail in Ontario to the E of the upr
rdg axis and allow a warm/humid SW flow arnd sfc hi pres over the SE
Conus to dominate the Upr Lks just to the S of a W-E oriented stnry
fnt just N of Lk Sup. The GFS fcst scenario would support above
normal temps/chcs for showers and TS while the ECWMF fcst would
result in aob normal temps/mainly dry wx except when that model
shows another shrtwv digging thru the Upr Lks on Thu. Considering
the sharp differences/plausible outcomes, wl maintain the consensus
fcst for now.

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1224 AM EDT FRI AUG 26 2016

A trough will drop through the area later on tonight. Behind it,
MVFR cigs should develop at all TAF sites late tonight into Friday
morning. Conditions will begin to improve Friday afternoon.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 335 PM EDT THU AUG 25 2016

Ahead of an approaching SFC trough, WSW winds will continue at 20-
30kt into this evening over much of the the W half of Lake Superior
today. Over eastern Lake Superior winds continue to be lighter, even
dropping below 10kt and becoming variable into this evening over
portions of S central Lake Superior as lake breeze circulation
develops. Stronger winds up to 20-25kt will then quickly develop
later this evening before winds diminish to below 20kt across the
entire lake late tonight into Fri morning after passage of the SFC
trough. Winds will diminish further to mostly under 15kt on Fri as
high pressure briefly builds over the area. Winds will be mostly
under 20kt through the weekend under a weaker pressure gradient.

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


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