Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 190536
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
136 AM EDT Fri Apr 19 2019

.SHORT TERM...(This evening through Friday)
Issued at 338 PM EDT THU APR 18 2019

A cloudy dreary day was observed across the Upper Peninsula, with
some locations downwind of Lake Superior seeing persistent fog and
light rain/drizzle throughout the morning hours. The expansive cloud
cover kept a lid on afternoon temperatures, as they only climb into
the mid to upper 30s in most spots. down across the south central,
where downsloping winds aided in further warmer temperatures climb
into the 40s.

Tonight, as shortwave energy continues to push east across the Upper
Peninsula scattered rain showers/drizzle will be possible. Out west,
where drier, colder air will start to work in later tonight, it is
not out of the question that precipitation switches over to or mixes
with snow in spots. Not expecting much in the way of accumulations.
Once deeper moisture continues to vacate the west half of Upper
Michigan, the combination of light winds, clearing skies, and recent
snowmelt/precipitation will allow for fog to develop. Across the
central and east, confidence is not as high in fog development given
the timing of drier air and vacating cloud cover.

Tomorrow will be a pleasant day across much of the area as high
pressure starts to tracks eastward. While we will see ample sunshine
across the area, the combination of warm temperatures inland and
downwind from Lake Superior, and broad northerly flow expected to
dominate will keep persistent cooler air coming in off of Lake
Superior. Therefore, keeping temperatures near the shoreline to be
quite a bit cooler (low to mid 40s) compared to further inland (mid
to upper 50s). With ample sunshine and drier air aloft expected,
deep mixing will develop and favor the transport of drier air aloft
and breezy northerly winds down the surface. RHs will likely lower
into the upper teens to lower 20s, especially where downsloping will
further enhance drying and warming.

.LONG TERM...(Friday night through Thursday)
Issued at 427 PM EDT THU APR 18 2019

During the long term, a lower amplitude, split flow pattern will be
the rule across the CONUS/southern Canada. With a more zonally
oriented northern stream flow that keeps cold air bottled up well to
the n and allows Pacific air to spread across the CONUS, temps
across Upper MI each day this weekend thru next week will be around
normal or above normal. The warmest day will be Sat. Of course,
there will be the usual chilly conditions along the Great Lakes,
depending on the wind direction from day to day. As for pcpn,
fortunately, under the more dominate influence of the northern
stream, this will be a drier pattern that won`t aggravate snowmelt
runoff that will be continuing thru the period. A couple of
shortwaves passing across northern Ontario early next week may
generate some shra, but likely nothing of significance. Two more
northern stream shortwaves may affect the area next week, one
midweek and the other late week. Neither of these waves should
produce significant rainfall. Meanwhile, in the southern stream, a
trof will drift across the CONUS during next week. While this trof
should not impact the weather here, it will be a feature to monitor.
If the trof or any energy ejecting from it tracks far enough n or
links up with the northern stream, more significant rainfall could
spread into Upper MI.

Beginning Fri night/Sat, a clear/quiet night Fri night under sfc
high pres ridge drifting across the fcst area will be followed by a
warm day on Sat, especially so over western Upper MI under southerly
winds. With sfc high pres ridge still over far eastern Lake
Superior/eastern Upper MI and northern Lake MI during the day Sat,
it will be cooler along the Lakes though it may warm up quite a bit
near Lake MI before winds shift onshore. Will be cool along Lake
Superior from n central Upper MI into the Keweenaw as winds back
under developing lake breeze wind component. Over the w, a continued
dry air mass and late morning 850mb temps around 5C will support
temps rising well into the 60s. Some of the traditional warm spots
may touch 70F. Given the still very dry air avbl for mix down as the
boundary layer builds during the day, once again incorporated some
of the drying based on mixing heights to lower dwpts. Interior min
RH may fall to 15-20pct Sat aftn. As non forested areas/grassy areas
continue to open up with snow melting away, these areas will become
ready for fire starts.

Shortwave moving across northern Ontario Sat night/Sun will send
associated cold front across the area. Timing of this front is much
better with today`s 12z model runs than it was 24hrs ago. Front
should be over central Upper MI at 12z Sun and will exit the e
during the aftn. Some -shra will be possible in the vcnty of the
front. ECMWF has been trending a little farther n with energy
ejecting from the southern stream trof over the western CONUS in
addition to having a more favorable upper jet configuration in the
upper level confluence zone across northern Ontario early next week
(better right entrance upper diffluence over the northern Great
Lakes). As a result, it has been trending toward a wetter scenario
Sun/Mon. There is some support for this solution from the CMC
ensembles, but not as much from the GFS. For now, this fcst has
modestly increased pops.

The next northern stream wave will pass in the midweek period,
bringing the next chc of -shra. Whether or not there is some link up
with the southern stream trof drifting e across the CONUS remains to
be seen.
&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 135 AM EDT FRI APR 19 2019

VFR conditions will continue through the period at all sites. There
will be some ground fog in and out of IWD overnight.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 338 PM EDT THU APR 18 2019

Behind the low pressure system winds will turn north to northwest
and diminish in speeds through the overnight hours, to below 20
knots. Winds will remain below 20 knots through the weekend and into
early next week.
&&

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

$$

SHORT TERM...Ritzman
LONG TERM...Rolfson
AVIATION...07
MARINE...Ritzman



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