Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 281954
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
354 PM EDT SUN AUG 28 2016

.SHORT TERM...(This evening through Monday)
Issued at 353 PM EDT SUN AUG 28 2016

Tonight, Low-level jet increases to 30 kt in response to shortwave
approaching from the Northern Plains and becomes oriented toward the
far western CWA. Increasing waa and theta-e advection along with
MUCAPE values increasing to near 1000 j/kg could generate some sct
shra/tsra late tonight over far west. Farther e, slow moving sfc
high pres ridge and axis of min precipitable water around 2/3rds of
an inch suggest leaning toward the low side of guidance for mins
tonight. Expect interior locations over the e to fall into the 40s.
Even over the central, a few spots could drop blo 50F if clouds are
slow to increase. Temps radiating through dewpoints could also
produce patchy fog over inland central and eastern areas of CWA.

On Mon, series of weak shortwaves in westerly flow aloft will bring
the approach of a cold front from west late Mon aftn or Mon evening.
Theta-e advection aloft ahead of the front could result in sct
showers and isold tsra as early as Mon morning. At the least,
consensus of models indicates good deal of mid-high clouds with a
few light showers. NAM/GFS and various high res guidance point to
weakening cluster of tsra moving into west half of Upper Michigan on
Mon morning. Extent of convection on Mon morning dictates how much
instability is present during the aftn as the front approaches.
Models show MLCAPEs increasing to 1000-1500 j/kg in the afternoon
generally over the west half of the CWA. Strong storms certainly are
possible with that extent of instability but effective shear is
barely over 20 kts so would seem that severe potential is low attm.
Mon looks to be a warm and humid day with dwpnts pushing over 60
degrees. Max temps near 80 or into low 80s seems good possibility
with even just a few breaks in the clouds during the day.

.LONG TERM...(Monday through Saturday)
Issued at 319 AM EDT SUN AUG 28 2016

On Mon, westerly flow aloft in wake of the strong trough moving
through attm brings a cold front in late Mon aftn or Mon evening.
Theta-e advection aloft ahead of the front could result in showers
and isold tsra as early as Mon morning. At the least, consensus of
models indicates good deal of mid-high clouds with a few light
showers. NAM/GEM and various high res guidance such as NCEP WRFs
point to weakening cluster of tsra roaming over west half of Upper
Michigan on Mon morning. Extent of convection on Mon morning dictates
how much instability is present during the aftn as the front
approaches. Even if there is minimal sfc based convection in the
aftn, there is potential for elevated convection on Mon evening
before the front crosses with sfc-h85 winds fm the wsw pushing 1-6km
MUCAPE up to 1000j/kg at least over the west cwa. Strong storms
certainly are possible with that extent of instability but effective
shear is barely over 20 kts so does seem that severe potential is low
attm. Shear is stronger over northern Minnesota and with expected
storm motion seems that greatest chance for severe over the cwa would
be on Mon evening over far west vcnty of IWD. Mon looks to be a warm
and humid day with dwpnts pushing over 60 degrees. Max temps near 80
or into low 80s seems good possibility with even just a few breaks
in the clouds during the day.

Front moves through early on Tue but secondary cold front moves
through late Tue morning into Tue aftn. May still be enough
instability and lingering moisture to kick off more showers and
thunderstorms over mainly south and east cwa. Latest ECMWF is slower
with departing qpf than previous three runs were. Not sure if that is
a trend or an outlier. Will keep some small chances going all day,
especially if another shortwave moves through in the wnw flow aloft.

High pressure builds over west cwa on Tue and will dominate across
all the cwa Tue night into the rest of the workweek. Upper trough in
vcnty on Wed along with h85 thermal trough with temps down to 6c
could support a few showers. Better shot of showers will be north
and east of Lk Superior across Ontario closer to track of shortwave
within the trough. Cool airmass could provide couple chilly nights
Tue night and Wed night and possibly Thu night too.

High slides east by next weekend allowing warm front to lift across
the Upper Great Lakes region. Theta-e advection will gradually bring
chance of showers and thunder back to the region. Depending on how
quick the instability axis progresses could see some rain as early
as late Fri night into Sat morning. Greatest chances as it look now
would occur later in the weekend just ahead of a cold front working
toward the region from the Northern Plains.
&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 132 PM EDT SUN AUG 28 2016

Morning low clouds have finally eroded and expect VFR conditions to
continue at all taf sites at least through this evening. Radiation
fog could develop at SAW overnight under sfc high pressure and near
calm wind and have included MVFR vsby in taf there. Scattered
showers/t-storms may also develop at IWD late tonight into Monday
morning with increasing warm advection ahead of approaching trough
over the Northern Plains so have included VCSH in IWD taf.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 353 PM EDT SUN AUG 28 2016

Expect winds mostly under 20kt through the middle of next week as
pres gradient remains generally weak. If stronger winds do occur,
Tue/Wed would be the time frame as a high pres ridge builds toward
the area in the wake of cold front passage Mon night/early Tue
morning. Eastern Lake Superior would be favored for the stronger
winds.
&&

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

$$

SHORT TERM...Voss
LONG TERM...JLA
AVIATION...Voss
MARINE...Voss


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