Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 231144
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
744 AM EDT FRI SEP 23 2016

.SHORT TERM...(Today and tonight)
Issued at 452 AM EDT FRI SEP 23 2016

Pattern still ongoing transition to greater amplification across the
CONUS with a prominent mid/upper level ridge developing from the se
CONUS through central Canada and an amplified trough digging through
the Rockies with its associated closed low moving from Utah this
morning into Colorado this evening. Upper Mi has been dry early this
morning in confluent flow ahead of amplifying mid-upper level ridge
over the Northern Plains and subsequent sfc high pressure building in
from Ontario/Manitoba. There have been some lingering mid-clouds over
all but the Keweenaw likely aided by lingering mid-lvl moisture and
some weak lift from shortwave trough moving through the Upper Lakes.

Today, expect mid clouds to erode later this morning over the area
as the weak shortwave passes to the east and is replaced by q-vector
divergence spreading in from Ontario. Despite the expected increase
in sunshine, the cool ENE low-level flow over the area will keep max
temps near normal, from the lower 60s north to mid-upper 60s south.

Tonight, the models still suggest that a band of mid-lvl fgen will
develop in response to the amplifying ridge to the west and upper
level div with the right entrance of the 250-300 mb jet to the
northeast. Also isentropic ascent will be increasing late tonight
from the west as noted on 350k sfc. Still, this forcing and increase
in mid-level moisture will be fighting through a dry low-level
airmass and large-scale anticyclonic flow under the dominant sfc
high centered over Ontario. For this reason, I`m skeptical that any
pcpn will reach into our far western counties before 12z Sat, but
will keep going slight chc pops in for late tonight given there are
still a few models printing out some QPF late.

.LONG TERM...(Saturday through Thursday)
Issued at 336 AM EDT FRI SEP 23 2016

Nam shows a shortwave ridge over the Upper Great Lakes 12z Sat with
a trough over the Rockies. The trough moves into the northern and
Central Plains Sat night and into the upper Great Lakes on Sun into
Sun night. Deeper moisture and dynamics arrive Sun morning over the
area and then head east Sun into Sun night. Basically, did not make
too many changes to the going forecast. Have likely pops spreading
across the area on Sun into Sun night. Did not make too many changes
to the going temperatures either.

In the extended, GFS and ECMWF show a 500 mb trough over the
northern plains and upper Great Lakes 12z Mon which moves very
little through Wed. GFS hangs this trough around while ECMWF moves
it east with shortwaves rotating around it helping to reinforce the
trough. Both models were different yesterday as well. Both drop the
trough into the lower Great Lakes by 12z Thu and this is followed by
a shortwave ridge that builds into the Upper Great Lakes. Confidence
continues to be low for this forecast as the extended models
continue with different solutions. Slow moving system does move out
and temperatures look to be at or slightly above normal for this
forecast period.
&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 744 AM EDT FRI SEP 23 2016

A fairly dry ne veering e flow arnd hi pres bldg into nw Ontario wl
result in predominant VFR conditions at the TAF sites this fcst
period.
&&

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 452 AM EDT FRI SEP 23 2016

NE flow over Lake Superior with SFC trough over the Lower Midwest
and SFC ridge building in from Canada will support some higher wind
gusts of 20-25 knots mainly over the western half of the lake into
this evening. As the Canadian high builds more over the Upper Lakes,
winds will dip below 20 kts late tonight into Saturday night.
Southerly winds will increase Sun afternoon into Sun night 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.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&

$$

SHORT TERM...Voss
LONG TERM...07
AVIATION...Voss
MARINE...Voss



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