Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 301134

Area Forecast Discussion
National Weather Service Marquette MI
734 AM EDT THU JUN 30 2016

.SHORT TERM...(Today and tonight)
Issued at 424 AM EDT THU JUN 30 2016

A sharp and stacked trough currently over the Manitoba/Ontario
border will pivot around a stacked low over extreme southern Hudson
Bay today into this evening. In the absence of any other mid to
upper-level forcing, this trough axis will promote a band of showers
and some thunderstorms across the CWA today. Expect precip to
gradually expand in coverage through this morning while tracking ESE
across the west and central as the trough begins to interact with
better low-level moisture evident in a higher low-level theta-e axis
advecting ahead of the low-level portion of the trough. Therefore
maintained categorical PoPs spreading across the central and east
late this morning into this evening. Showers will end from WNW to
ESE this evening as the trough swings across the CWA, though some
lingering low-level moisture will allow light showers to hang on for
several more hours for mainly the N to NW wind upslope regions of
Lake Superior.

While initial instability will be marginal, some destabilization
will occur across the SE half of the CWA before cloud cover thickens
after noon. This is especially true along Lake MI and the south-
central, where afternoon MLCAPE values surpass 1000 J/kg. Much of
this instability should be realized as the approaching trough
interacts with a lake-modified boundary from SSW winds off Lake MI
and Green Bay. Though deep-layer shear will be lacking ahead of the
trough, low web-bulb freezing levels of 9-10kft will support small
hail with any pulsing cell that manages to become relatively

.LONG TERM...(Friday through Wednesday)
Issued at 501 AM EDT THU JUN 30 2016

Mid/upper level troughing from Hudson Bay to the Great Lakes and ern
Canada into Saturday will give way to a zonal pattern across the nrn
CONUS and srn Canada early next week as an omega blocking pattern
develops over nrn Canada. However, some ridging from the nrn plains
into Sask/Manitoba that gradually slides to the east will maintain
wnw flow into the Upper lakes.

Friday through Sunday, confluent mid/upper level flow and high pres
building over the area will bring dry weather to region with mostly
clear skies. Cool conditions on Friday with breezy nw winds and
highs in the 60s to lower 70s will rebound into the 70s to near 80
for Sat/Sun when light winds and prominent lake breezes prevail.

Mon-Wed, There is more uncertainty as for several runs, the ECMWF
has hinted at potential for convection developing and move near or
just north of the CWA from mon into mon night as 850 mb theta-e
ridging/instability develops and spreads from the nrn plains toward
wrn Ontario and the nrn Great Lakes and wnw flow shrtwvs brush the
region. The GFS/GEFS/GEM maintain a stronger ridge, keeping the area
dry. Slight or lower end chance pops continue tue into wed given the
proximity to the unstable air to the sw and potential for additional
shrtwvs moving through the region. However, the models maintain
enough mid level or sfc riding to limit pcpn potential and keep
mainly dry weather going.

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 734 AM EDT THU JUN 30 2016

A cold front crossing Upper Michigan will bring SHRA and possibly
some thunderstorms to all sites from west to east today. The best
chance for TSRA among the sites will be mid-afternoon at KSAW.
Otherwise, expect ceilings to fall to at least the MVFR range with
the showers. Favorable upslope winds will then allow both KCMX and
KSAW to lower to IFR ceilings for a period behind the showers before
drier air brings improving conditions tonight.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 424 AM EDT THU JUN 30 2016

A cold front crossing Lake Superior late today will allow west winds
to quickly veer northwest to north at 15 to 25 knots this afternoon,
especially across the east half. The stronger winds will continue
well into Friday before persistent high pressure brings winds under
15 knots late Friday through the 4th of July.

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


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