Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 191145

Area Forecast Discussion
National Weather Service Marquette MI
745 AM EDT Mon Mar 19 2018

.SHORT TERM...(Today and tonight)
Issued at 451 AM EDT MON MAR 19 2018

WV imagery and RAP analysis indicated confluent mid/upper level flow
through nrn Ontario into the nrn Great Lakes between a trough from
Quebec into nrn New England and a ridge from IA into the ern
Dakotas. This supported a building sfc ridge from nrn Manitoba into
the Great Lakes which was bringing cool dry air into Upper Michigan
on ene low level winds. Otherwise, IR loop showed an area of mid
clouds spreading from ne MN into portions of north and western Upper

Today, ne flow CAA will drop 850 mb temps to around -12C and keep
temps below normal with highs from the  mid and upper 20s north to
the lower 30s south. min temps at the top of the shallow cold layer
to 3k ft will provide only marginal instability for any LES. The
very dry low level air with dewpoints around 10F will also be
unfavorable for any diurnal -shsn development.

Tonight, although the slowly veering ne winds will be light enough
to allow decent radiational cooling, there may be enough cloud
cover to keep temps from dropping off too far. Nevertheless,
expect min readings will still drop a bit below guidance from 5 to
10 inland to 10 to 15 near the Great Lakes. The dry air will
remain unfavorable for any pcpn beyond a few flurries that may
develop north central in upslope flow.

.LONG TERM...(Tuesday through Sunday)
Issued at 244 AM EDT MON MAR 19 2018

Looks like quiet weather will persist through much of the week. A
weak upper level trough will bring an increase in mid-level clouds
Tue into Wed but low-level dry air in a ne flow circulating around a
Hudson Bay high should ensure dry conditions. The mid level clouds
combined with the cool ne flow off Lake Superior will keep temps blo
normal Tue into Wed with highs in the upper 20s north to lower to
mid 30s south.

Upper ridge from the west begins to shift into the Upper Great Lakes
Thursday and Friday yielding more sunshine as temps push back toward
normal with highs in the lower to mid 30s north to upper 30s south.

Next weekend mainly on Saturday, the 00Z Canadian model indicates
pcpn (mainly in the form of snow) reaching into mainly the sw and
south central portions of Upper Mi, associated with a stronger
shortwave moving through the Upper MS Valley. It is likely that the
northern portion of the pcpn shield from this shortwave will be
impeded by continued dry east to northeast low level flow from the
Hudson Bay high as suggested by the drier 12Z/00Z ECMWF solutions
and now the latest 00z GFS solution. At this point, will keep low
chc pops in for light snow over the sw and south central fcst area
based on model consensus, but could easily see drier solution of
12Z/00Z ECMWF and 00z GFS verifying given strength of persistent
ridging from Hudson Bay into the Upper Great Lakes.

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 745 AM EDT MON MAR 19 2018

Mainly VFR conditions are expected through the TAF period with
periods of mid clouds. However, upslope ne flow of colder air will
support a greater chance for MVFR cigs at KSAW by late this evening
that will persist overnight.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 451 AM EDT MON MAR 19 2018

High pressure building in from Ontario will produce ne winds around
25 knots over western Lake Superior today into tonight. Otherwise
no significant winds are expected through the forecast period,
with winds generally staying at or below 20 knots.

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


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