Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 260649

Area Forecast Discussion
National Weather Service Marquette MI
249 AM EDT Fri May 26 2017

.SHORT TERM...(This evening through Friday)
Issued at 414 PM EDT THU MAY 25 2017

WV imagery and RAP analysis indicated mid/upper level trough over
the wrn CONUS with a downstream ridge from the cntrl plains through
the upper MS valley into nw Ontario. At the surface, riding also
prevailed from the lower MS valley through WI to wrn Lake Superior.
Vis loop showed mostly sunny skies over most of nrn Upper Michigan
with sct/bkn cu over the south. Moisture and a weakening deformation
zone with a mid level low from OH to Lake Huron supported clouds and
light rain over far eastern Upper Michigan.

Tonight, the slowly progressive pattern will allow the sfc ridge to
build into cntrl and ern Upper Michigan. A period of partly to
mostly clear skies this evening will allow temps to drop into the
mid and upper 40s. There should also be enough mosture, dewpoints in
the mid 40s, along with the period of favorable radiational cooling
for some fog formation. 850-700mb WAA with 295k-305k isentropic lift
may also support light rain over nw WI that could spread into the
wrn cwa late. However, since the lift weakens as it moves eastward
only slight chance pops were included.

Friday, as the sfc trough moves to the east and a weak shortwave
trough lifts toward wrn Lake Superior, lower end pcpn chances across
the west half will increase, mainly during the late afternoon. Even
with temps climbing to around 70 inland, instability to support tsra
remains west of the cwa.

.LONG TERM...(Saturday through Thursday)
Issued at 248 AM EDT FRI MAY 26 2017

Nam shows a closed 500 mb low north of Lake Winnipeg with a trough
extending down into the northern plains into the central Rockies 12z
Sat. This trough moves slowly east and affects the upper Great Lakes
Sat night through Sun night. Nam has some q-vector convergence Sat
night into Sun that moves through the area. With troughing in the
area, pops pretty much anytime cannot be ruled out. Overall, have
some low chance pops in for much of the forecast period and did not
make too many changes to the going forecast.

In the extended, GFS and ECMWF show a 500 mb trough over the central
U.S. 12z Mon with a ridge in the western U.S. which remains
stationary into Tue. The ridge moves into the Rockies 12z Wed, but
the upper Great Lakes still remains in the upper trough into Thu.
Temperatures still look to remain below normal this forecast period.
No real dry periods, but not a total washout either.

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 121 AM EDT FRI MAY 26 2017

VFR conditions will likely prevail at KIWD/KCMX thru this fcst
period. VFR conditions will also prevail at KSAW with the exception
of early this morning when radiation fog may develop. Vis should
fall to MVFR, perhaps lower. Winds at all terminals will be under
10kt thru the period.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 414 PM EDT THU MAY 25 2017

Expect winds under 20 kts through early next week as a relatively
flat pres gradient dominates the Upper Lakes.

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


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