Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 260757
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
357 AM EDT TUE JUL 26 2016

.SHORT TERM...(This evening through Tuesday)
Issued at 349 PM EDT MON JUL 25 2016

Main issue in the short term related to chances for showers and
thunderstorms tonight and Tuesday.

A shortwave trough currently over central Manitoba will move into
northern Ontario tonight. As it does so, a LLJ will develop and nose
into western Lake Superior tonight. May see some showers and
thunderstorms move into the western lake tonight into Tuesday
morning. None of these storms are expected to be severe as
instability is marginal.

A weak shortwave is then set to cross the area Tuesday
afternoon/evening, which should allow for convection to develop.
SBCAPE will increase to 1000-1500 J/kg with effective shear of 20-25
kts. Certainly not expecting widespread severe storms, but can`t
rule out an isolated strong to severe wind gust and small hail,
especially on storms that stick to the Lake Superior lake breeze.
Looking at several high-res models, the best chances for precip will
be over the central U.P.

.LONG TERM...(Wednesday through Monday)
Issued at 357 AM EDT TUE JUL 26 2016

Wednesday and Wednesday night: A cold front is progged to continue
sagging southward through the area Wednesday before stalling to the
south of the U.P. Wednesday night. A shortwave is progged to slide
through the Upper Great Lakes region Wednesday afternoon and evening
before sliding south and east of the area Wednesday night.
Steeper lapse rates associated with the shortwave along with
increased forcing across the southern U.P. will help to increase
chances for showers and thunderstorms. Again, the southern areas of
the U.P., in closer proximity to the slowing cold front, will have
the better chances due to increased forcing. MUCAPE values are
progged to be between 1000-2000 J/kg Wednesday afternoon/evening
south of the front. The severe weather potential looks low at this
point, through this time period as shear values are only expected to
be around or below 25-35 knots, oriented along the forcing
mechanism. Some of the storms during the afternoon/evening may pulse
up and become strong to severe, on a very isolated basis, but
organized/widespread severe weather is not expected. Storm motion
would most likely be from the west at or around 30 to 35 mph. The
main threat from any of the stronger storms would be small hail and
gusty winds.

Thursday through Friday night: High pressure and dry air is still
progged to slide into the area from Canada by Thursday morning and
then linger through this time period. Aloft, the Upper Great Lakes
region will be under a slight troughing pattern to near zonal flow.
This flow along with fairly dry air in place will keep the bulk of
the precipitation to the south of the U.P., while also helping to
keep temperatures closer to or slightly below normal for this time
of year. For reference, normal highs are right around 77 while
normal lows are around 55. The coolest night is expected to be
Thursday night as the surface ridge is centered overhead. This will
allow skies to clear and wind to become light and variable. The
combination of light winds, clear skies and precipitable water
values around 50 percent of normal will provide ideal radiational
cooling conditions. Inland locations may drop down into the low to
mid 40s for Thursday night.

Saturday and Saturday night: The aforementioned high pressure system
will slide to the east of the area through this time period.
As this happens, warmer and more moist, southerly flow will return
to the Upper Great Lakes region. Aloft, it looks as if there may be
a shortwave that slides across the area late Saturday, bringing
small chances for showers and thunderstorms.  Details will be fine-
tuned as the weekend approaches as the exact timing will be key for
increased chances of showers and thunderstorms.

Sunday through Tuesday: An upper-level 500mb ridge is expected to
build across the Upper Great Lakes region allowing temperatures to
warm above normal once again and reducing the chances for showers
and thunderstorms through Monday night. Models then hint at an
approaching cold front for Tuesday, but there are differences in
timing of the front for Tuesday; therefore, have gone with a
consensus of the models.  This will keep a chance of showers and
thunderstorms in the forecast for Tuesday.
&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 137 AM EDT TUE JUL 26 2016

VFR conditions continue through the forecast period. An upper level
disturbance moving through the region this afternoon will trigger
scattered showers and possibly a few thunderstorms, with most of
this convection limited to the southern sections of the Upper
Peninsula.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 349 PM EDT MON JUL 25 2016

Winds will diminish this evening as the pressure gradient weakens.
Winds for the remainder of the forecast period will be mostly 15kt
or less.
&&

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

$$

SHORT TERM...Titus
LONG TERM...KEC
AVIATION...RJT
MARINE...Titus


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