Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 230542
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
142 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
area.

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...(Friday night through Thursday)
Issued at 409 PM EDT THU JUN 22 2017

The wet and cooler than normal trend will continue through much of
the extended portion of the forecast.

The general trend for much of the extended forecast continues to be
the troughing over the east half of the CONUS with ridging expected
to linger over the west half. The main impact that this will have on
the weather in the U.P. will be increased cloud cover along with
intermittent chance for 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
synchronized with the multiple shortwaves sliding around the trough
the area. At this point, the more widespread focus will likely be
Saturday through Sunday, mainly in the afternoon, as a stronger
upper-level disturbance slides through or just south of the U.P.
Temperatures will generally be in the mid to upper 60s with
overnight lows in the 40s to around 50.

Toward the end of the extended forecast, Tuesday through Thursday,
models are trending toward a bit of a brief break in the troughing
across the area. This will allow a brief ridge to build in ahead of
a cold front that is expected to slide into the area Wednesday into
Thursday. As the front slides through Wednesday afternoon into
Thursday, the chance of showers and thunderstorms will return once
again. Ahead of this front and under the ridge, temperatures will
warm closer to normal with highs in the mid to upper 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.
&&

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

$$

SHORT TERM...Rolfson
LONG TERM...KEC
AVIATION...JLB
MARINE...Rolfson



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