Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 230705

Area Forecast Discussion
National Weather Service Marquette MI
305 AM EDT Fri Jun 23 2017

.SHORT TERM...(This evening through Friday)
Issued at 406 PM EDT THU JUN 22 2017

Water vapor imagery and RAP analysis show a deep mid-level low over
southern Manitoba (500mb height anomalies around 230m). Low is
embedded in overall broad, low-amplitude troffing centered over
central N America. In the weakly cyclonic flow across the n central
CONUS, shra/tstms have been tracking from the eastern Dakotas/IA
toward Lower MI today, aided by right entrance of 120kt upper jet
extending from northern MN across northern Ontario and low to mid
level frontogenesis. Northern edge of this pcpn extends about as far
n and w as a Watersmeet to Marquette line.

As upper jet axis and frontogenesis drift se tonight, ongoing shra
and isolated embedded thunder will also shift se. Much, if not all,
of the shra should be se of the fcst area by 06z. Otherwise, over
the next 24hrs, the deep mid-level low over southern Manitoba will
open up as it moves ese, with remnant vort max passing across
northern Lake Superior Fri aftn. Ahead of it, another shortwave trof
currently over MT/ND will also shift e, moving across Upper MI late
tonight/Fri morning. Not really anything going on ahead of the
latter wave. Farther w and nw under colder mid-levels, isold shra
are developing in nw ND. Given arrival of wave late tonight/Fri
morning, these shra will likely have dissipated before reaching the

On Fri, remnant of the Manitoba mid-level low will arrive at a more
favorably aligned time with respect to daytime heating. Lingering
low-level moisture over the eastern fcst area combined with Lake
Superior lake breeze aided windshift may support sct -shra over the
eastern fcst area inland from Lake Superior in the aftn. No mention
of thunder was included in fcst. However, with model consensus for
mlcape of a couple hundred j/kg, not out of the question that there
could be a rumble or two of thunder. To the w, cooling mid-levels
under somewhat sharper troffing might support a few sprinkles or an
isolated -shra inland. At this point, lack of instability suggests a
mention of pcpn in fcst is not warranted. Otherwise, looks like a
breezy day under deep mixing. Expect gusts to 20-30mph over the w
and central, strongest over the Keweenaw. Deep mixing should also
support dwpts falling to or blo lowest guidance, but no fire wx
issues given the surplus of rainfall over the last couple of weeks.

.LONG TERM...(Saturday through Thursday)
Issued at 305 AM EDT FRI JUN 23 2017

The wet and cooler than normal pattern for the weekend into early
next week will transition to a warmer but still fairly active
pattern for mid to late next week.

Ridging over the western CONUS and over Greenland will allow a broad
mid-upper level trough to persist over the east half of the CONUS
for the weekend into early next week. As a result, Upper Mi can
expect increased cloud cover along with periods of rain showers and
isolated afternoon thunderstorms. The better chances for rain will
occur with the diurnal instability cycle, during peak heating in the
afternoon and syncronized with a series of shortwaves sliding
through the trough and across the Upper Lakes. At this point, it
looks like the best chances will likely be Saturday through Sunday,
mainly in the afternoon, as a couple of stronger shortwaves slide
just south of the region. There will be some lingering showers on
Monday, but coverage may be more isolated to scattered over mainly
the east half, as the mid-level trough axis and associated sfc
trough push east. Temperatures Sat thru Mon will generally be in the
60s with overnight lows in the mid 40s to around 50.

Models are trending toward a break in pcpn for Tue as a confluent
flow develops ahead of the advancing mid-level ridge over the Plains
and sfc ridging builds into the area. The sfc ridge will move east
Tue night in advance of a cold front that will slide into the area
late Wednesday into Thursday. As the front slides through the chance
of showers and thunderstorms will return once again. A few of the
models also indicate MUCAPEs of 1000-1500 j/kg along with deep layer
shear near 30 kts so there may also be a threat of strong to
possibly severe storms with convection that moves through the area
late Wed into Thu. Ahead of the front and under the ridge at least
Tue into Wed, temperatures will rebound closer to normal with highs
in the 70s and lows in the mid to upper 50s.

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 142 AM EDT FRI JUN 23 2017

VFR conditions are expected to prevail at KIWD/KCMX/KSAW through the
forecast period with sct-bkn diurnal cu developing by Friday
afternoon. Gusty winds will develop Friday morning, especially at
KCMX which is more exposed to westerly winds. Gusts up to 30kt are
expected late morning thru the aftn.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 406 PM EDT THU JUN 22 2017

Vis satellite imagery has given hints of patchy fog on Lake Superior
today. This patchy fog may linger tonight and then perhaps thru Fri
over far eastern Lake Superior. Winds will remain generally below
20kts into early next week. Stongest winds should occur later
tonight thru Fri evening when gusts may reach 20-25kt at times.

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


SHORT TERM...Rolfson
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