Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 180507

Area Forecast Discussion
National Weather Service Marquette MI
1207 AM EST Wed Jan 18 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 325 PM EST TUE JAN 17 2017

12Z raobs/latest wv imagery and RAP analysis show a general zonal
flow present over Canada and the nrn tier of the CONUS. There are a
pair of shrtwvs over the Great Lks that were responsible for the
light wintry mix of pcpn that impacted the se cwa this mrng, but as
these disturbances have pressed to the ese, the diminishing dynamic
support and arrival of dry air shown on the 12Z INL raob have caused
this pcpn to diminish and skies to begin clrg over the nw half.
Since h85 temps are above 0C in the zonal flow of Pacific air, sfc
temps are running well above normal, mainly well into the 30s. A sfc
hi pres rdg axis is present upstream over MN under the large scale
subsidence ahead of shrtwv rdg axis trailing the departing
disturbances. Some fog did dvlp last ngt under this rdg axis. There
is a strong disturbance moving e across nrn Manitoba, and some hi
clds on its srn flank extend s into the nrn Plains.

Tngt...Large scale subsidence/mid lvl dry air ahead of aprchg shrtwv
rdg axis wl bring dry wx tngt and clrg of lingering clds now mainly
over the se half of the cwa. With this clrg, expect some fog to dvlp
over mainly the se half of the cwa, where winds wl be lighter thru
the ngt under incoming sfc rdg axis and the lingering clds wl dspt
later in the day and restrict diurnal warming/then allow for more
diurnal cooling. Although the disturbance crossing central Canada
and the associated sharper forcing wl remain well to the n of Upr
MI, the earlier tightening pres gradient/stronger sw winds and
arrival of some hi clds over the nw half of the cwa wl restrict the
diurnal temp fall and the potential for any fog in that area.

Wed...After any lingering fog burns off in the mrng, Wed wl turn
mosunny with nothing more than some hi clds lingering to the s of
the passing Cndn disturbance. H85 temps are fcst to peak as hi as 7-
8C, so tended toward the hier end of guidance for max temps,
especially in areas impacted by the downsloping wsw flow. Expect
temps to rise aoa 40 away fm some cooling off Lk MI.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 325 PM EST TUE JAN 17 2017

Longer range forecast continues to prog an above normal period for
temperatures, with a high degree of confidence. Pattern has remained
suggestive that high amplitude ridging will reside over the Great
Lakes and for the most part the eastern half of the CONUS. There are
a few areas of concern for the later portion of the week, with
guidance pivoting a embedded shortwave lifting north across the
plains towards the Great Lakes late Thur into Fri/Sat. Thermal
profiles suggest the bulk of any precip will fall as liquid;
however, during the nocturnal periods as the surfaces cool, some of
the precip could begin to fall as sleet/freezing-rain Fri ngt/Sat.

With the shortwave trapped within the 500mb ridge, it will not be
very progressive so expect periodic chances for precip throughout
the weekend into early next week. Then beyond Mon ensembles begin to
lean towards 500mb ridging re-developing across the Central Plains
and eventually lifting northeast towards the Great Lakes region.
This will likely displace the main flow of systems further north
across the Northern Plains into Ontario/Hudson Bay and clip the U.P.
Temperatures throughout the extended, as eluded to earlier, will
generally be in the mid/upr 30s, but could easily see several
locations touching 40 degrees.

Dew points will also be on the rise over the weekend into early next
week, which could indicate some potential hydro concerns depending
on the duration of above freezing Td`s, which helps to accelerate
the loss of snowpack.

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1202 AM EST WED JAN 18 2017

With good radiational cooling conditions across the area, patchy
dense fog has developed with the most persistent VLIFR vsby at
SAW. The fog has been more variable at IWD and CMX. Expect that
the fog at SAW will linger into Wednesday morning. Confidence is
lower at CMX but there still is the potential for some periods of
VLIFR fog. Since the sw winds will increase over the west, fog is
less likely at IWD. LLWS should also develop Wednesday morning as
west winds increase above the surface inversion. Fog may redevelop
again by later Wednesday evening.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 325 PM EST TUE JAN 17 2017

Expect light winds under 15kt into this evening to become wsw up to
25-30kts late tonight into Wed as the pres gradient tightens between
a hi pres passing thru the Lower Great Lakes and lo pres crossing
central Canada/Hudson Bay. As the low continues eastward and the
pres gradient weakens, winds will diminish Wed afternoon/night.
For the remainder of the week, expect winds under 20kts as
conditions become unseasonably warm over the Upper Lakes with no
significant weather features impacting the area.

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


LONG TERM...Beachler
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