Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 210729

Area Forecast Discussion
National Weather Service Marquette MI
329 AM EDT Sat Apr 21 2018

.SHORT TERM...(Today and tonight)
Issued at 329 AM EDT SAT APR 21 2018

High pressure from Hudson Bay to the lower Great Lakes will refocus
with center over the lower Great Lakes by daybreak Sunday. Some high
clouds moving through now and that has kept temps mainly in the 20s
early this morning. These clouds will drift out of the area this
morning and with the high pressure overhead, expect another day with
mostly sunny conditions. Temps aloft slightly warmer than Fri, so
made sure forecast inland temps were a couple degrees warmer than
Fri. Result is temps into the mid 60s inland west and reaching well
into the 50s elsewhere. Temps along the Great Lakes will run up to
the lower, maybe mid 50s by early aftn but then fall off again this
aftn as lake breezes develop. Though fire weather is not much of a
concern at this point, continued to cut dwpnts compared to most
guidance as they have been too moist lately. With high pressure and
airmass of very dry Hudson Bay origin, pretty apparent it is going
to take stronger moisture advection than just melting snow to boost
low-level moisture to levels most models are showing the last few
days. Have a feeling this moist bias in the models will continue
until snow pack is gone.

High pressure and light winds tonight, along with less cloud cover
than currently observed, should lead to slightly cooler temps mainly
in the upper teens to lower 20s inland and in the mid to upper 20s
near the Great Lakes.

.LONG TERM...(Saturday night through Friday)
Issued at 241 PM EDT FRI APR 20 2018

NAM shows a closed 500 mb low in the central plains 00z Sun.
Shortwave ridging moves into the upper Great Lakes Sat night. This
ridge remains over the area through Sun. Quiet and dry weather
through Mon with temperatures above normal.

In the extended, GFS and ECMWF show a 500 mb trough over the
southeastern U.S. and another trough over the northern and central
plains 12z Tue. The trough over the plains moves through on Tue into
Tue night. Another shortwave moves into the upper Great Lakes 12z
Thu and this shortwave digs into the lower Great Lakes 12z Fri. Will
see some rain and snow showers out of this. Temperatures slip back
to below normal for most of this forecast period.

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 124 AM EDT SAT APR 21 2018

Thanks to surface high pressure and ridging aloft remaining in
control over the region, VFR conditions with light and variable to
calm winds will continue to prevail through this TAF period at all
three terminals. Could see some mid-to upper-level clouds gracing
the skies through early Saturday.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 329 AM EDT SAT APR 21 2018

Winds will remain less than 15 knots through most of the period.
Main exceptions would be northwest winds over 20 kts possible later
Tue into Tue night and again late Thu into Thu night in wake of cold
fronts moving across Lk Superior.

Issued at 440 AM EDT FRI APR 20 2018

Snowpack will be melting through at least early next week under
warming which will push temps to around normal or even slightly
above normal. Mostly sunny days thru the weekend will strongly aid
the melting. With nighttime temps falling blo freezing and dewpoints
likely remaining low, only a gradual increase in melting/runoff
should occur. Early next week, min temps may not fall blo freezing
for a night or two, increasing runoff potential, though dewpoints
will likely remain low, keeping melting of snow slower than would
otherwise occur. The addition of notable rainfall is the biggest
concern to increase flooding potential. Fortunately, there will be
no pcpn thru the weekend, and pcpn which occurs Tue/Wed should be on
the light side as a cold front passes. Temporary cool down following
the frontal passage will then slow down the ongoing snow melt.
Overall, these conditions don`t suggest any significant concerns
with the snow melt over the next 7 days. While melting will likely
be relatively controlled given the forecast, rivers will begin to
respond this weekend and minor flooding is quite possible at some
point down the road on the usual rivers that experience spring

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


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