Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 201911

Area Forecast Discussion
National Weather Service Marquette MI
311 PM EDT Sun Aug 20 2017

.SHORT TERM...(Today and tonight)
Issued at 500 AM EDT SUN AUG 20 2017

WV imagery and RAP analysis indicated zonal mid/upper level flow
across the nrn CONUS with the main upstream shortwave trough over
wrn Manitoba. At the surface, sw flow was increasing over nrn MN and
Lake Superior between a ridge from PA into lower MI and nrn WI and a
cold front into the nw corner of MN.

Today, Expect that with plenty of sunshine and sw flow WAA pushing
850 mb temps to around 17C, highs will climb into the mid 80s, with
the higher readings in downslope locations near Lake Superior and
lower temps in the mid and upper 70s downwind of Lake Michigan. The
warming combined with dewpoints in the lower to mid 60s will result
in MLCAPE values in the 1k-2k J/Kg range. As the front moves into
the area along with lake breeze boundaries, sct shra/tsra should
develop by mid to late afternoon over the nw half and spread into
cntrl Upper Michigan early this evening. There is still some
uncertainty with the coverage/POPs with the amount of capping as the
stronger qvector conv and height falls remain well to the north.
With 0-6km shear values in the 30-35 knot range, some organized
stronger convection may develop with the potential for small hail
along with gusty winds. Relatively high freezing levels around 14k
ft will limit the potential for larger hail.

Tonight, the sct shra/tsra should move through the rest of the cntrl
and ern cwa between 00z-06z with drier air moving into the west
overnight behind the front.

.LONG TERM...(Monday night through Sunday)
Issued at 311 PM EDT SUN AUG 20 2017

As main upper trough moves into the Upper Great Lakes on Monday
night...a wave will develop along the frontal boundary stalled out
just south of the area. As the waves lifts east
northeastward...precipitation shield will move across central
and eastern sections of the U.P. The rain should move east of the
area by Tuesday monring. A reinforcing cold front will drop
southward across Lake Superior by late in the day Tuesday.  It`s
passage should be dry but it will usher in a stretch of cool but
tranquil weather for mid to late week.

Return flow warm advection regime returns for next weekend as will
the next chances of rain for the area.

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 146 PM EDT SUN AUG 20 2017

VFR conditions expected through the period. There could be scattered
showers or thunderstorms at each TAF site this afternoon into early
this evening as a cold front crosses the region but the best chance
will be at SAW. Patchy fog may develop at KSAW tonight, but a lot of
that will hinge on whether rain occurs at the TAF site.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 500 AM EDT SUN AUG 20 2017

Winds will remain at or below 20 knots through the first half of the
work week as the pressure gradient remains fairly weak across Lake
Superior. Southwest winds may gust close to 25 knots this afternoon
ahead of a cold front moving through, but it should be for a short
duration. The next chance for gusty winds will be Wednesday as low
pressure slides to the northeast of Lake Superior. Northwest winds
may gust as high as 25 knots during that time period.

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


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