Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 231951
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
351 PM EDT Fri Jun 23 2017

.SHORT TERM...(This evening through Saturday)
Issued at 350 PM EDT FRI JUN 23 2017

Tonight: As a shortwave shifts to the east of the area this evening
and daytime instability decreases, expect any of the few lingering
showers to diminish. This will lead to a mainly dry night across
much of Upper Michigan. There is a small chance that a few showers
may form late tonight over the northwest half of the area as a weak
surface trough approaches from the north. Thunder should not be an
issue overnight; however, as instability remain low. Would not
really expect too much more than a trace of rain over the
northwestern U.P. late tonight.

Saturday: The aforementioned surface trough will linger across the
area throughout the day as another/stronger upper-level disturbance
slides just south of the U.P. This added forcing from the surface
trough, along with steeper lapse rates, will allow scattered showers
and thunderstorms to develop across the U.P. The boundary being
nearly overhead will allow cloud cover to increase and showers to
develop earlier in the day; however, the coverage is expected to
become more widespread during the peak heating of the afternoon.
Some of the showers and thunderstorms may drop some heavy rain over
a short period of time, mainly over the south central and the
eastern portions of the U.P. Saturday afternoon. Severe weather
threat is expected to be margingal; however, the south central and
eastern portions of the U.P. could see some small hail from any
stronger thunderstorms that develop. This is largely due to
increased instability over those area along with freezing levels
dropping to around 6kt. Not much shear at all and the MUCAPE is only
around 600 - 1000 J/kg over the south central and east, so not
expecting anything more than the occasion pulsing thunderstorm with
small hail potential.

.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 18Z TAFS through 18Z Saturday afternoon)
Issued at 141 PM EDT FRI JUN 23 2017

VFR conditions can be expected at each of the TAF sites through late
tonight. There will be some diurnal CU at each of the TAF sites this
afternoon, but it should remain at or above 4kft with only small
chance for rain showers. Late tonight through Saturday morning, a
weak surface trough and upper level disturbance will approach the
area. This will give increasing chance for rain showers at each of
the TAF sites by late Saturday morning with ceiling expected to
lower to or near MVFR conditions. Visibility should be good at each
of the TAF sites, even under some of the rain showers.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 350 PM EDT FRI JUN 23 2017

Winds will increase to 15 to 25 knots this evening, then decreasing
during the overnight hours into Saturday morning to around 10 to 15
knots. Winds of 10 to 15 knots are expected to continue into early
next week as the pressure gradient decreases and high pressure
builds in for the first part of the work week.
&&

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

$$

SHORT TERM...KEC
LONG TERM...Voss
AVIATION...KEC
MARINE...KEC



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