Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 221149

Area Forecast Discussion
National Weather Service Marquette MI
749 AM EDT THU SEP 22 2016

.SHORT TERM...(Today and tonight)
Issued at 529 AM EDT THU SEP 22 2016

Models still doing a remarkably poor job handling convection or
lack thereof over the region early this morning. Much of the
convection is focused well to the south of Upper Mi into central
Wi early this morning along 850 mb warm front and in area of best
850 mb warm advection. Only city of Menominee getting brushed by
this convection with a few showers in past hour, and dry NE
low-level flow ahead of sfc high now poised to build in fm south
central Canada later tonight and Friday has kept much of the cwa dry
overnight. Some showers continue to generate over the MN arrowhead
aided by forcing in right entrance region of 120-130 kt 250-300 mb
jet max over Ontario and assoc 700 mb frontogenesis and perhaps some
conditional instability as noted by neg EPV in 650-500 mb layer.
These showers are moving out mostly over northern Lake Superior but
occasionally a few have passed over the Keweenaw Peninsula.

Today into Tonight...Generally followed closer to regional Canadian
model for forecast details as it overall had a much better handle on
current convection than the NCEP models.  The Canadian model shows
the building sfc high from southern Canada continuing to push frontal
boundary and associated warm advection over central WI farther south
through the day which follows along with recent radar trends. As a
result expect any lingering showers over MNM county to get pushed
south of the area later this afternoon if not sooner. Would expect
any lingering showers over the Arrowhead of MN to dissipate as well
toward 12z with gradual influx of drier air from the nw assoc with
the building high.

NE flow over the area combined with persistent cloud cover through
most of the day will ensure cooler high temps today generally in the
lower 60s most areas...except mid to upper 60s for downsloping along
the Bay of Green Bay and Lake Mi. Models suggest clouds may even
persist into tonight and this combined with continued NE gradient
flow could keep temps from dropping off too much from daytime highs.
Look for mins tonight from the mid to upper 40s over the interior to
the lower 50s near the Great Lakes.

.LONG TERM...(Friday through Wednesday)
Issued at 303 AM EDT THU SEP 22 2016

Nam forecasts a 500 mb ridge over the plains with a closed 500 mb
low and trough over the central and southern Rockies 12z Fri. This
ridge moves into the upper Great Lakes 12z Sat and remains over the
area into 12z Sun while the 500 mb trough and low move northeast
into the northern Plains. The frontal zone and pcpn will get pushed
south and will be dry until late Fri night and Sat morning when a
wave will try to bring some pcpn into the west, but only have slight
chance pops for now. Next wave and chance for pcpn comes in for Sat
night and have chance pops in for the west half late. Overall, did
not make too many changes to the going forecast.

In the extended, GFS and ECMWF show a 500 mb ridge on the west
coast, a trough in the northern plains and a ridge in the Great
Lakes and sern U.S. 12z Sun. This trough moves slowly east 12z Mon
with it starting to affect the upper Great Lakes. Upper air pattern
becomes increasingly amplified with very little movement to the east
through the forecast period with a slow moving sfc low pressure and
several fronts affecting the area this forecast period. Looks wet
with a slow moving system and temperatures look to be at or slightly
above normal.

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 730 AM EDT THU SEP 22 2016

Although only isolated showers are expected over the area today, the
presence of low lvl moisture near the warm fnt to the s of Upr MI wl
allow for MVFR cigs to develop at both IWD and SAW thru this mrng
and into much of the aftn. There could even be a period of IFR cigs
at IWD this morning. Since CMX is closer to the drier air, expect
cigs to remain VFR at that site. The arrival of drier air wl cause
improvement later this afternoon in the TAF period. The upslope ne
flow should allow for MVFR cigs to redevelop at SAW late tonight.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 529 AM EDT THU SEP 22 2016

NE flow over Lake Superior with SFC trough over the Lower Midwest and
SFC ridge building in from Canada could support some higher wind
gusts of 20-25 knots mainly over the western half of the lake into
Fri evening. As the Canadian high builds more over the Upper Lakes,
winds will dip below 20 kts Friday night into Saturday night.
Southerly winds will increase late Sunday into Mon to 25 to 30 knots
over mainly the north central and eastern part of the lake as a low
pressure trough approaches from the west.

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


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