Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 161741

Area Forecast Discussion
National Weather Service Marquette MI
141 PM EDT Sun Oct 16 2016

.SHORT TERM...(Today and tonight)
Issued at 414 AM EDT SUN OCT 16 2016

00Z raobs/latest wv imagery and RAP analysis show a shrtwv/sfc lo
pres near James Bay exiting to the ene ahead of a shrtwv rdg axis
moving thru the nrn Plains. Cold fnt attendant to the departing
James Bay lo pres and accompanying showers have clrd the ern cwa
ahead of a hi pres rdg moving into MN under the Plains shrtwv rdg/
larger scale subsidence. Although some fog lingers over mainly the
se cwa, the influx of very dry air depicted on the upstream raobs,
where 00Z pwat was as lo as 0.41 inch at INL, in the nw flow ahead
of the approaching hi pres rdg is clearing any leftover clds acrs
the e. Farther upstream, a strong shrtwv is moving newd into the nrn
Rockies out of the base of a trof along the Pac NW coast. Local
raobs show 12hr h5 hgt falls arnd 100m associated with this

Main fcst concerns in the short term wl focus on pops tngt
associated with aprch of vigorous shrtwv now moving into the nrn
Rockies and associated sfc lo pres/warm fnt.

Today...Passing sfc hi pres rdg/very dry airmass ahead of shrtwv rdg
axis that is fcst to reach the wrn Great Lks late today wl result in
mosunny conditions for Upr MI. With h85 temps topping out arnd 10C,
expect max temps to rise well into the 60s away fm the cooling
influence of Lk Sup in the veering n to ne llvl flow. Some mid/hi
clds ahead of upstream waa in advance of the nrn Rockies shrtwv
moving out into the nrn Plains wl arrive over the w by later in the

Tngt...Sharpening pres gradient btwn shrtwv/lo pres moving e fm the
nrn Plains toward Upr MI and retreating hi pres rdg wl allow for
axis of vigorous waa powered by h925-85 llj ssw winds up to 40-45
kts/isentropic lift best shown on the 300-305K sfcs/area of deep lyr
qvector cnvgc to pass across the Upr Lks. This forcing will bring a
band of showers arriving fm the sw near the WI border arnd 06Z and
then overspreading the rest of the cwa except for perhaps the far e
by 12Z. Maintained a mention of some elevated TS as many of the
models show SSIs a few degrees blo 0C/mucapes aoa 500 j/kg with h85
temps as hi as 13-14C. Most recent SPC outlook has the WI border
zones on the edge of a marginal elevated svr wx risk in WI for hail
with steep h7-5 lapse rates up to 7C/km. With the waa/steady winds/a
good deal of clds, temps wl run above well above normal, especially
over the w where the thicker clds/stronger waa wl arrive earliest.

.LONG TERM...(Monday through Saturday)
Issued at 354 AM EDT SUN OCT 16 2016

Nam shows a 500 mb ridge over the southern plains and a broad trough
over the western U.S. 12z Mon with a shortwave moving into the upper
Great Lakes. Another shortwave ejects out of the broad trough and
moves into the upper Great Lakes Mon night. GFS and ECMWF show about
the same thing as well and will use a blend of them for this
forecast. Have likely pops in for most of Mon and Mon night for the
cwa. Bumped pops up a bit on Mon for the cold front that moves
through the area. Other than that, did not make too many changes to
the going forecast.

In the extended, GFS and ECMWF show a 500mb broad trough over the
Rockies 12z Wed with a ridge over the sern U.S. with a ridge on the
west coast. A trough moves into the northern plains 12z Thu with
850mb temperatures  dropping to -4C. This trough digs into the
central U.S. 12z Fri with 850 mb temperatures still remaining at -4C
over Lake Superior. With Lake Superior temperatures running from 9C
to 12C, this is enough lake-850 mb delta-t for lake effect pcpn. The
trough moves into the ern U.S. 12z Sat with a broad 500 mb ridge in
the western U.S. Temperatures will stay near normal to slightly
below normal for this forecast period.

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 141 PM EDT SUN OCT 16 2016

VFR conditions will linger through this afternoon into early this
evening. A warm front will lift northward toward the area by late
evening, bringing showers and a few thunderstorms to IWD first and
then to the rest of the TAF sites overnight. Ceilings will drop to
IFR overnight tonight at each TAF site with some visibility
restrictions due to rainfall. A low level jet will also develop
overnight which will introduce LLWS to all of the TAF sites with
shear values approaching 40 kts.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 414 AM EDT SUN OCT 16 2016

Nw winds up to 20 kts today ahead of an approaching hi pres ridge
will veer to the e by this evening and then to the se late tonight
while increasing up to 25-30 kts under the tightening pres gradient
between the hi pres ridge departing to the e and an approaching lo
pres from the northern plains. Expect the strongest se winds up to a
gale force 35 kts to occur over eastern Lake Superior late tonight
into Mon morning. After coordination with Environment Canada, opted
to issue a gale warning for this area for 09Z-15Z Mon. These strong
winds will diminish thru the day on Mon as the lo pres/weaker
gradient moves over the Upper Lakes. As another lo pres moves ne
near Upper MI late Mon into Tue, a strong NW wind up to 25-30 kts
will develop in its wake before weakening to about 20 kts or less
Tue night thru Thu with the approach of a hi pres ridge/weaker

Upper Michigan...
Lake Superior...
  Gale Warning from 5 AM to 11 AM EDT Monday for LSZ266-267.

Lake Michigan...


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