Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 280535

Area Forecast Discussion
National Weather Service Marquette MI
135 AM EDT SAT MAY 28 2016

.SHORT TERM...(This evening through Saturday)
Issued at 345 PM EDT FRI MAY 27 2016

SW flow aloft bringing multiple minor shortwaves across Upper Great
Lakes. Leftover weak shortwave has helped drive cluster of shra
and isold thunderstorms as far north as Menominee county and Bay
of Green Bay. Pocket of mucapes over 500j/kg also supporting these
showers and storms which should lift into central cwa next few
hours. Additional scattered showers are streaming north across WI
and western Upr Michigan. Not much thunder seen though as sfc based
or elevated CAPES are fairly meager, generally less than 500j/kg.
Scattered showers and an isold thunderstorm expected early this
evening based on radar trends over Upper Great Lakes. As another
shortwave and sfc front/weak low pressure wave lift toward Upr
Michigan later this evening, expect another round of widespread
showers with at least a slight chance of thunderstorms as elevated
cape remains less than 250j/kg. Another mild night with temps mainly
in the 50s and fog should develop again, though probably
later as the rain moves through initially.

Chances for showers and thunderstorms continues on Sat. Put a lull
in during the morning as subsidence behind the wave that moves
through tonight will probably lead to a min in coverage. Models
are in agreement with that idea, though with this type of pattern
near term convection will depend on individual shortwaves that are
hard to determine at this point. Daytime heating should increase
coverage of showers and thunderstorms in the aftn. Will depend on
how much instability is realized. Some hint that low clouds may
hang around til midday, so that would alter forecast of sfc based
CAPEs up to around 1000j/kg. Also think there will be better chances
in afternoon as upper level trough and sfc trough are closer to the
region attm. High temps should reach at least low 70s and could
reach upper 70s if there is enough sunshine.

.LONG TERM...(Saturday night through Friday)
Issued at 319 PM EDT FRI MAY 27 2016

Nam shows a trough in the wrn U.S. with a shortwave over the
Mississippi River valley 00z Sun with a ridge over the ern U.S. This
shortwave moves across the upper Great Lakes Sat night and Sun.

Confidence continues to be low for this forecast overall as it
depends heavily on amount of convection which influences the cloud
cover which influences the temperatures. Hard to time the shortwaves
out and how much convection will fire with them which in turn
influences how much cloud cover and the temperatures. For now, will
not make very many changes to the going forecast and will have some
chance pops to low likely pops into Sunday night and then will keep
Memorial Day dry for now. Is not out of the question that there
could be some lake breeze convection that forms on Memorial Day as
GFS and NAM both generate a little qpf, but thinking right now is
that this is overdone and will keep dry. Will not change
temperatures much from the going forecast.

In the extended, GFS and ECMWF show a 500 mb closed low and trough
over the northern plains and another over the desert SW 12z Tue. The
trough over the northern plains moves slowly east 12z Wed and moves
into the upper Great lakes 12z Thu and this remains over the area
into Fri. Still looks unsettled this forecast period with
temperatures near normal. Mon night and Fri look to be the driest
for this forecast for right now.

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 135 AM EDT SAT MAY 28 2016

An area of showers will lift northward across the eastern half of
the UP through the early morning hours. Moist easterly flow off fog
covered Lake Superior has already lowered cigs/vsbys at CMX into LIFR
range and that should persist through the overnight hours. As has
happened the last couple of nights cigs/vsbys will also lower into
the IFR range at IWD and SAW with the moist airmass in place.
Daytime heating will allow scattered showers to develop almost
anywhere over the western half of the UP during the day on Saturday
but there will be some improvement in cigs/vsbys by mid morning.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 345 PM EDT FRI MAY 27 2016

A relatively weak pres gradient/hi stability will dominate the Upper
Great Lakes this forecast period, so expect winds at or below 20kts.
Since moist air will linger over the chilly lake waters, dense fog
will linger into at least Sun. Dense fog should begin to diminish
early next week as drier air arrives from the northwest.

Upper Michigan...
Lake Superior...
  Dense Fog Advisory until 6 PM EDT /5 PM CDT/ Sunday for LSZ162-

Lake Michigan...
  Dense Fog Advisory until 4 PM EDT this afternoon for LMZ248-250.



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