Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 242328

Area Forecast Discussion
National Weather Service Marquette MI
728 PM EDT Sat Oct 24 2020

.SHORT TERM...(This evening through Sunday)
Issued at 414 PM EDT SAT OCT 24 2020

Sfc analysis shows a trough/cold front moving southeast across
eastern Lake Superior and the Keweenaw Peninsula this afternoon. As
this front continues to push se across the rest of the cwa this
afternoon and evening, winds will shift from westerly to more n-nw
behind the front late today into tonight. The result will be that w-
e oriented lake effect snow bands affecting mainly areas along Lake
Superior today will become oriented more nw to se tonight and maybe
even eventually n-s later on Sunday bringing light lake effect snow
farther inland across the U.P.

With an absence of any shortwave to help enhance les and model
soundings indicating inversion heights at or blo 5 kft along with
generally drier air beneath the inversion, expect any additional les
accumulations to be light later today into early Sunday. Expect
accumulations to generally be an inch or less with favored spots for
accumulating snow over the higher terrain of Ontonagon and Gogebic
County and eastern Marquette and western Alger counties where low-
level convergence is maximized.

Lake effect snow could increase in coverage/intensity during the day
on Sunday as a shortwave moving in from the west along with deeper
moisture provides additional enhancement. Weakly cyclonic northerly
flow will favor the higher terrain of Marquette and possibly Baraga
counties for 1-2" of lake effect snow during the day on Sunday as
SLRs should be around 15:1. The rest of the CWA should see
generally see snow amounts of an inch or less.

.LONG TERM...(Sunday night through Saturday)
Issued at 309 PM EDT SAT OCT 24 2020

Upper air pattern consists of a deep 500 mb trough in the Rockies
and northern plains 00z Mon with ridging on the Gulf Coast and also
off the west coast. The northern plains shortwave moves into the
upper Great Lakes 12z Mon. Upper troughing remains over the upper
Great Lakes Mon into Tue. Light pcpn moves out Sun night with
highest pops across the east and south and then drier weather moves
in for Mon with lake effect pcpn still possible. Overall, nothing
big to note in this time period and made very little change to the
going forecast.

In the extended, the GFS and ECMWF show a broad 500 mb trough over
the northern U.S. 12z Wed with a ridge on the west coast. A sfc cold
front will be moving through the upper Great Lakes 12z Wed. A
shortwave moves into the upper Great Lakes 12z Thu. The 500 mb ridge
moves into the Rockies 12z Fri and into the upper Great Lakes 12z
Sat with troughing moving into the northern plains. Temperatures
will remain below normal for this forecast period until Sat when
temperatures go to near normal. Pretty quiet for this forecast
period with very limited moisture to work with.

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 727 PM EDT SAT OCT 24 2020

Westerly winds shift to the north tonight at all three TAF sites,
keeping the potential for widely scattered to scattered lake effect
snow showers going for all locations. Ceilings will vary from VFR to
MVFR with the lower ceilings associated with the snow showers.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 414 PM EDT SAT OCT 24 2020

Ridging will remain over the lake tonight into Monday as winds
should stay blo 25 knots.

Low pressure moving east through Manitoba and Ontario Tue night
early Wed will result in increasing southwesterly winds on Tue.
Winds over the western half of the lake should increase to low end
gales and near 30kts in the east. As the low brushes the northern
shoreline and then moves east, winds will subside blo gales Thu into

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


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