Area Forecast Discussion
Issued by NWS Marquette, MI
FXUS63 KMQT 130522
Area Forecast Discussion
National Weather Service Marquette MI
1222 AM EST Fri Jan 13 2017
.SHORT TERM...(This evening through Friday)
Issued at 359 PM EST THU JAN 12 2017
Short description of the upcoming conditions (see the WSW and SPS
for more info).
A shortwave cross through the area is leading to strong winds that
have already increased over the western CWA. Winds will continue to
turn out of the WNW tonight, especially impacting the Keweenaw and
lakeshore areas E of Munising with blowing/drifting snow and light
LES. Continued the winter wx advisory for the Keweenaw given very
low VIS occuring and expected to continue. Issued an SPS for NE U.P.
as winds will be more isolated to the lakeshore. Wind chills will
drop to -25F to -30F over the interior W tonight into Fri morning,
so issued a wind chill advisory there.
Snow gradually diminishes in the NW wind snowbelts through FRI.
.LONG TERM...(Friday night through Thursday)
Issued at 326 PM EST THU JAN 12 2017
A hi pres rdg near the Great Lks wl bring generally dry wx to the
area this weekend. Although the weekend wl start on a seasonably
chilly note, there wl be a warming trend into early next week as upr
hgts begin to rise with the arctic branch retreating n into Canada
and an upr rdg building over the se CONUS. Depending on the track of
a polar branch shrtwv/sfc lo pres lifting ne fm the srn Plains on the
nw flank of the se upr rdg, there wl probably be a mixed pcpn event
arnd Tue. Pacific air and well above normal temps wl dominate much of
Fri ngt/Sat...A clipper shrtwv embedded in the arctic branch flow is
fcst to track across Ontario to the n of a hi pres rdg stretching fm
the ne states into the Upr MS River Valley. A lo pres trof associated
with the clipper is fcst to cross Lk Sup during this time. But with
an absence of any sgnft mstr inflow and the passage of the sharper
dpva/deep lyr qvector cnvgc to the n closer to the shrtwv track,
expect any accompanying pcpn to be light and limited mainly to areas
near Lk Sup. Some of the guidance does show a weak disturbance
tracking thru WI and bringing some lgt pcpn to the scentral right
under the sfc rdg axis, but if this pcpn does occur it wl be light.
Depending on the cld cover associated with this disturbance, some
locations over the scentral could be quite chilly on Fri ngt with
lighter winds closer to the hi pres rdg axis just to the s. More clds
and a stronger wsw flow over the nrn tier wl limit the diurnal temp
fall in that area. As h85 temps warm to arnd -8C on Sat, expect max
temps to rebound into the 20s.
Sat ngt thru Sun ngt...Hi pres is fcst to build over the Upper Lks
and bring dry wx to the cwa under rising upr hgts as the arctic
branch flow retreats into Canada and an upr rdg builds over the se
CONUS downstream of a trof over the sw states. There wl be a slow
warming trend as h85 temps recover to -2C to -4C on Sun. Lowered fcst
min temps blo the consensus on Sat ngt in areas away fm lk
moderation with light winds and moclr skies.
Mon thru Tue ngt...Concern during this time wl focus on the timing/
pops/ptype associated with shrtwv/sfc lo pres lifting out of the sw
trof toward the Great Lks. Although Mon is likely to be dry until at
least early aftn, some of the faster models indicate some waa sn
well ahead of the sfc lo wl arrive over the scentral in the aftn.
While the longer range guidance continues to show some variability on
the fcst mass/thermal fields with uncertainty on the interaction btwn
the primary shrtwv and another disturbance in the plains, current
trends sug the heaviest pcpn wl fall on Tue and over the central and
ern cwa. Since the bulk of the models show h85 temps rising aoa 0C
over much of the cwa, the associated pcpn is likely to be wintry mix.
Wed/Thu...Expect a drying trend on Wed following the passage of the
disturbance/sfc lo pres to the ne. The zonal flow of Pacific air in
its wake is fcst to lift h85 temps as hi as 5C on Wed, so expect
well above normal temps. This warm, dry wx wl linger on Thu with the
persistent flow of Pacific air.
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1221 AM EST FRI JAN 13 2017
Gusty west winds that have resulted in considerable blsn have
diminished but LES will persist keeping vsby in the IFR/LIFR range.
Winds will gradually diminish overnight with improving vsby as some
light lake effect snow showers continue into Friday morning. The LES
will end by Friday afternoon as high pressure builds into the area.
At IWD, MVFR conditions with light LES will give way to VFR
conditions as winds back to the west.
VFR conditions will prevail at SAW through the forecast period.
However, lake effect clouds may reduce cigs near the MVFR threshold
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 326 PM EST THU JAN 12 2017
Expect wnw gales to 35-45 kts under the tight pres gradient between
a lo pres moving into Quebec and hi pres building into MN to slowly
diminish under gale force late tonight with the slow approach of the
hi pres/flatter pres gradient. Not out of the question there could
be some storm force gusts this evng. The hi waves whipped up by the
strong winds and very cold arctic air surging into the area will
result in heavy freezing spray that will diminish on Fri as the
winds/waves subside. As the pres gradient sharpens between a lo pres
crossing Ontario and the hi pres moving to the e on Fri night, expect
sw winds to increase up to 30 kts and then shift to the w following a
lo pres trof passage on Sat. But then as the hi pres builds closer
later on Sat into Sun and lingers into Mon, expect winds to diminish
under 20-25 kts. As a lo pres approaches from the sw later on Mon
into Tue, winds will shift to the e-ne. Since this lo pres is
forecast not to deepen significantly, winds are now expected to
remain under 25 kts.
Winter Weather Advisory until 1 AM EST early this morning for
Wind Chill Advisory until 10 AM CST Friday for MIZ009-010.
Heavy Freezing Spray Warning until 11 AM EST this morning for
Gale Warning until 4 AM EST early this morning for LSZ245>251-
Heavy Freezing Spray Warning until 9 AM EST this morning for
Gale Warning until 1 AM EST /midnight CST/ early this morning
Heavy Freezing Spray Warning until 7 AM EST /6 AM CST/ this
morning for LSZ240>242-245>247-263.