Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 151843

Area Forecast Discussion
National Weather Service Marquette MI
243 PM EDT Thu Mar 15 2018

.SHORT TERM...(This evening through Friday)
Issued at 243 PM EDT THU MAR 15 2018

Benign weather expected for at least the next 36 hours, and likely
to persist into the medium/longer term periods as well.

High pressure continues to drift east from the Upper Midwest/Central
Canada, which will steadily erode the lingering shallow moisture and
bring an end to the lake-effect snow showers across central/eastern
UP this afternoon. Skies have already cleared across the western UP,
and expect a gradual push to the east this evening/overnight. As a
result, temperatures for the central/western UP will quickly radiate
tonight given optimal conditions. Have held onto the current
forecast lows of single digits below zero across the west and some
areas of the higher terrain across central UP. Further east, it
apppears clouds will linger and thus help to hold temps up in the
single digits above zero to perhaps the lower teens.

High pressure will be positioned overhead Fri, allowing a very light
pressure gradient to produce light to calm winds from the
west/northwest. Temps will steadily rebound into the 30s and
eventually warm to near 40 across interior portions of southwest UP.

.LONG TERM...(Friday through Wednesday)
Issued at 402 AM EDT THU MAR 15 2018

A quiet stretch of late winter/early spring weather is on the way
thru next week. Currently, an amplified ridge extending from the
western Plains n thru the Northwest Territories is supporting a deep
trof over the eastern CONUS. Over the next few days, the upstream
ridge will fade away, and split flow will become more pronounced
across N America thru the middle of next week. With the northern
stream featuring a trof over eastern Canada, shortwaves and
associated pcpn tracking across the CONUS in the southern stream
will likely be forced s of Upper MI by the eastern Canada trof.
During the last half of next week, ridging will build across the
Plains then shift to the Great Lakes in response to a trof
developing into the western CONUS. These large scale changes will
support a dry period of weather for Upper MI. It`s quite possible
that many locations will not see any pcpn for the next 7 days, and
the dry weather may even extend thru the end of next week, depending
on how progressive the late week pattern is across the CONUS. There
will be some LES off Lake Superior today which will diminish/end
from w to e this aftn/tonight. The only other potential of any pcpn
over the next 7 days, and that looks doubtful, will be early next
week as a shortwave dropping into the eastern Canada trof pushes
colder air into the Upper Lakes, possibly cold enough to support a
little light LES off Lake Superior. As for temps, readings on most
days won`t stray far from normal, but max departures from normal
will be as much as around 10 degrees over the next few days. The
coldest day will be today and the warmest day Sat.

Beginning Fri/Sat...With sfc high pres dominating Fri, expect a
sunny day though there may be some stratocu over the e in the
morning before 850mb temps moderate further. Expect high temps in
the 30s, but some locations over the interior w may reach 40F. A
very weak sfc trof will slip s across the area Fri night with
essentially no impact on the weather. Under mostly clear skies/light
winds, favored the global CMC bias corrected for mins since it is
typically a superior performer on radiational cooling nights.
Traditional cold spots should see temps bottom out around 5F. Temps
will range up to 15-20F near the Great Lakes. Model RH fields
suggest there be some sct clouds on Sat, particularly across the n
and e. High temps will be higher than Fri, rising well into the 40s
over the interior w half.

Shortwave tracking thru northern Ontario will send a cold front s
across Upper MI late Sat night or Sun morning. Limited
moisture/forcing and 850mb temps too high to support lake
enhancement as the front passes suggest fropa will likely be dry.
Models have waivered on the degree of CAA in the wake of the cold
front, but the last 24-36hrs of models runs have generally suggested
850mb temps only perhaps just reaching the marginal threshold for
LES. Given that the low-level flow will become notably anticylonic
by the time the coldest air arrives, it seems unlikely that any LES
will develop Sun night into Mon. Meanwhile, shortwave tracking
across the CONUS in the southern stream early next week is likely to
pass well s of the area due to the se Canada troffing in the
northern stream. Compared to the last 2 runs, there are considerably
fewer CMC ensembles now in the 00z run that track the wave far
enough n to bring pcpn into the fcst area, and there are only a few
GFS ensembles that do. Medium range models do show an inverted sfc
trof extending from the sfc low back into the Dakotas/western MN in
response to an upstream shortwave diving from the western Dakotas
toward the mid Mississippi Valley. SE track of this energy while sfc
high pres dominates northern Ontario to provide a feed of dry air
suggests this pcpn will not reach Upper MI. As a result, will carry
a dry fcst Mon thru Wed. Building mid-level ridge shifting from the
Plains to the Great Lakes should then maintain dry weather Thu/Fri
as well.

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 118 PM EDT THU MAR 15 2018

Lake effect clouds have started to clear across the south with VFR
conditions now being observed at KIWD.  However, the clouds are
persisting around KCMX and KSAW with low confidence in when they
will finally erode. Associated light lake effect snow showers also
continue at KSAW with occasional drops in visibility to IFR
conditions. Admittedly there is low confidence in just how long the
clouds and snow will continue at KCMX and KSAW, respectively, but
the expectation is for VFR conditions to gradually spread eastward
to all TAF sites this afternoon and evening. This TAF package is on
the pessimistic side with IFR conditions for visibility continuing
at KSAW for the next 1-2 hours followed by MVFR ceilings through
the evening, and MVFR conditions for ceilings continuing at KCMX
through the early afternoon hours.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 243 PM EDT THU MAR 15 2018

Light west/northwest winds overnight through Friday will be at or
below 20kts on Lake Superior. No significant winds are expected for
the next few days over Lake Superior.

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


SHORT TERM...Beachler
LONG TERM...Rolfson
MARINE...Beachler is the U.S. government's official web portal to all federal, state and local government web resources and services.