Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 261926

Area Forecast Discussion
National Weather Service Marquette MI
326 PM EDT Sun Mar 26 2017

.SHORT TERM...(This evening through Monday)
Issued at 320 PM EDT SUN MAR 26 2017

Water vapor imagery and RAP analysis show a mid level low centered
over northern IL. Deep moisture associated with this feature surged
back to the n across Upper MI last night into today, bringing
periods of -ra/-fzra. Upslope e to se flow also resulted in some
patchy dense fog this morning into early afternoon over portions of
the Keweenaw Peninsula...Dickinson and southeast Marquette counties.

Models show the mid-level low and assoc trough lifting ne through
Lower Mi this evening and then into Ontario late tonight/Mon
morning. With movement of the mid-level trough the 850mb trough and
weak isentropic ascent also shifts e tonight, so expect pcpn over
mainly the central and eastern fcst area to diminish. However with
abundant moisture, developing nnw upslope flow and approaching weak
shortwave, some -ra/-fzra will remain possible over the w tonight.
Sfc temps should slip back to around freezing over the w and n
central, so there may still be a little bit of icing at some
locations late tonight. However, accumulations should be minor so no
statement will be issued at this time. Expect some fog as well.

Weak northerly flow between sfc low over eastern Ontario and sfc
high building into south central Canada will result in murky weather
conditions with some fog and possible light drizzle or freezing
drizzle Mon morning mainly over upslope locations of west and north
central U.P. Forcing from incoming northern stream shortwave could
enhance upslope pcpn turning dz/fzdz to -ra/-fzra for a time late
morning into mid aftn. NAM soundings suggest could even be brief
period of sleet or snow mixing in over west and northwest with
evaporative cooling aloft. Limited moisture depth as noted on NAM
soundings will not warrant anything more than slight chc to low chc
pops. Expect highs in the mid 30s to lower 40s, warmest e and se
under cloudy skies.

.LONG TERM...(Monday through Saturday)
Issued at 425 AM EDT SUN MAR 26 2017

Split flow pattern across North America remains in place through the
upcoming week. Pattern lacks significant widespread precip through
Thu with next chance of widespread precipitation not arriving until
Thu night or Fri if the 12z GEM and EC are correct. GFS not in line
with that idea at all though as it keeps precip well to the south
of here so will have to wait and see how that works out.

On Mon morning, low pressure lifting to the central Great Lakes from
the middle Mississippi River valley will be located vcnty northern
Lk Huron to Georgian Bay. Main sfc high will be centered well to
north over far northern Manitoba. Weak north to northeast low-level
flow btwn the two features will result in murky weather conditions
with some fog and possible light drizzle or freezing drizzle. Precip
could be enhanced turning to light rain or light freezing rain for a
time morning to mid aftn as northern stream shortwave moves through.
Could even be small chance of sleet or snow mixing in over west and
northwest with evaporative cooling aloft. Moisture profiles above h9
from various models look too variable to hit up pops too much
though. Low level moisture gradually scours out Mon night into Tue
as high pressure over cntrl Canada builds toward Upper Great Lakes.
NNE winds out of the high leading to upslope flow could keep some
clouds in through at least Tue morning. Cut max temps Mon into Tue
some along Lk Superior with the gradient onshore flow.

Best chance for seeing sunshine will be later Tue and more so into
Wed as the high builds overnhead. Dropped highs slightly over the
north with the peristent gradient onshore flow out of the cool high
and crossing the chilly waters of Lk Superior.

As alluded to at the top a lot of differences still present with
late Thu into Fri system. GEM and ECMWF continue to indicate cutoff
low in the southern to central Plains Wed into Thu drifts far enough
northeast on Fri to bring rain across the Upper Great Lakes. GFS is
still completely dry for Fri as northern stream troughing moving
through on Thu keeps southern stream system well to the south across
the mid South and basically has no qpf into WI or lower MI. No clear
trends as GFS has shown its dry scenario for Fri for the couple days
and the ECMWF has shown the wetter idea over most of its recent
runs. GEM has bounced back and forth between these two ideas. Will
remain with consensus solution given the uncertainty.

Main issue from the precip would be possible freezing rain late Thu
night into Fri morning as rain first arrives and as dry east sfc
flow holds down temps. GEM would indicate this system becomes mainly
a rain producer Fri into Fri night, but ECMWF which phases more
northern stream energy into the approaching southern stream system
would suggest potential for some snow or mix of rain and snow. 00z
ECMWF trended colder and would have snow over most of the cwa for
Fri now. A consensus of all these solutions with ptype based mainly
on sfc temps resulted in chance pops for mainly snow on Thu night
going to chance pops for rain/snow on Fri. However, if the GFS and
UKMET farther south ideas are correct Thu into Fri would end up
pretty nice with plenty of sunshine and temps well into the 40s if
not pushing into the 50s. For sure have some details to be sorted
out as we get later into this week.

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 320 PM EDT SUN MAR 26 2017

Abundant low-level moisture persisting will continue the
LIFR cigs at KIWD/KCMX/KSAW thru this fcst period and cigs could
be near landing mins at KSAW and KCMX. Some -ra is expected at
times, especially at KSAW. Expect some fog as well, which could
drop vis to LIFR. &&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 320 PM EDT SUN MAR 26 2017

With no signIficant weather systems affecting the Upper Great Lakes
this week, no gales are expected on Lake Superior. In fact, winds
will mostly be under 20kt.

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


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