Area Forecast Discussion
Issued by NWS Marquette, MI

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002
FXUS63 KMQT 181724
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
Issued by National Weather Service GAYLORD MI
124 PM EDT Wed Oct 18 2017

.UPDATE...
Issued at 1138 AM EDT WED OCT 18 2017

13z surface/composite analysis shows a strong (974mb/4-5 SD below
the mean for mid October) cyclone over northern Manitoba...trailing
cold front south along the Red River of the North and into central
South Dakota. Warm front extends east well north of Lake Superior...
with a strong gradient across the Midwest and upper Great Lakes.
Strong short wave trough driving this front east in a progressive
pattern overall...but the air mass is quite dry ahead of this
feature (e.g., 12z APX/MPX soundings)...with the cold front devoid
of precipitation and only bands of high clouds ahead of the upper
wave.  Decent momentum below 850mb as well (southwest 20-35kt)...so
looking at a breezy afternoon with gusts 25 to 35 mph.  Afternoon
highs well into the 60s expected with some 70s over far western
Upper/Keweenaw Peninsula.
&&

.SHORT TERM...(Today and tonight)
Issued at 310 AM EDT WED OCT 18 2017

...Unseasonably warm and windy today...

Upstream of the region this morning, a deepening area of low
pressure was tracking across central portions of Saskatchewan, with
a cold front extending southward into the northern Plains. An
increasing pressure gradient associated with this system has allow
for periodically breezy winds overnight. Therefore, the nocturnal
boundary layer has struggled to decouple somewhat, this coupled with
return flow developing ahead of the approaching cold front has
allowed early morning temperatures to remain rather mild, in the 40s
and 50s.

The main forecast concern over the next 24 hours will the
continuation of unseasonably warm temperatures and the gusty winds.
High-res and medium-range models, along with ensembles all are
pointing towards gradient flows increasing throughout the day today.
Momentum profiles within BUFKIT are rather impressive, with 35 to 45
knots winds 500-1500 feet AGL. Even though there is some uncertainty
in how deep mixing will get given the reduced solar angle this time
of year, along with upper-level cloud cover increasing somewhat this
afternoon, it shoulnd`t take deep mixing to see southwest winds
gusting upwards of 30 to 40 mph later today. The strongest wind
gusts are expected to be in areas that see downsloping winds,
especially near Lake Superior. Across the east, especially locations
north of Lake Michigan, will also likely see stronger winds as upper-
level clouds will be last to arrive; however, modified cooler air
off of Lake Michigan may hinder the depth of mixing. Contemplated
issuing a wind advisory for the north central and eastern portions
of the forecast area; however, there is some uncertainty if we will
hit or miss wind advisory criteria. Therefore, upon collaboration
have opted to hold off on issuing an advisory for now. Temperature
wise, today will be unseasonably warm as we see afternoon highs
climb a few degrees warmer than yesterday. North of Lake Michigan,
temperatures will remain in the 60s; however, across the west and
central expect temperatures to climb near 70, if not into the low to
mid 70s in some locations. Areas that see downsloping winds across
the northwest and north central will have the best chance at seeing
low to mid 70s today.

Tonight, the above mentioned cold front will track eastward across
Upper Michigan. With little in the way of moisture available ahead
of this front, not expecting any precipitation to develop.
Challenging overnight low temperature forecast as winds should
slowly come down overnight; however, they may stay up just enough to
limit radiational coolings ability to take advantage of the drier
post frontal airmass. Did opt to keep the possibility of upper 30s
across the interior west as that area looks like it will have the
best chance at seeing wind speeds relax overnight. Otherwise, expect
overnight lows to drop into the 40s.

.LONG TERM...(Thursday through Tuesday)
Issued at 311 AM EDT WED OCT 18 2017

Upper level ridging moves into the upper Great Lakes on Thu and
lasts into Fri. Troughing moves into the Rockies and plains Fri
night. Did not make too many changes to the going forecast with
above normal temperature continuing.

In the extended, GFS and ECMWF show a 500 mb trough over the western
half of the U.S. and a ridge along the east coast 12z Sat. The
trough moves into the central U.S. 12z Sun with a sfc cold front
moving through the area. More upper level troughing moves in for 12z
Mon with the trough digging into the eastern U.S. 12z Tue along with
some colder air. Troughing remains over the eastern part of the U.S.
into Wed. Temperatures stay above normal through Monday and then
colder air moves in for Tue and Wed where temperatures return to
near normal. Best chance for rain is on Sun when a cold front moves
through the area.
&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 121 PM EDT WED OCT 18 2017

Only aviation concern will be gusty winds from the southwest this
afternoon...which should subside with loss of heating by early
evening. Some marginal low level wind shear possible...though
winds will be shifting this evening to the west with passage of a
cold front. VFR conditions expected through Thursday morning.

&&

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 644 AM EDT WED OCT 18 2017

Expect 20 to 30 knot winds out of the south-southwest today. A few
gale force gusts to 35 knots look possible, especially across the
eastern half of the lake later this afternoon. Tonight a cold front
will push eastward across the lake and veer wind around to the
west at 20 to 30 knots, with a few gale force gusts possible.
Thursday night through early next week, winds should remain around
or below 20 knots.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning until 8 PM EDT this evening for LSZ248-249.

  Gale Warning until 11 PM EDT this evening for LSZ250-251.

Lake Michigan...
  Gale Warning until 11 PM EDT this evening for LMZ248-250.

&&

$$

UPDATE...JPB
SHORT TERM...Ritzman
LONG TERM...07
AVIATION...JPB
MARINE...Ritzman



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