Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 251950

Area Forecast Discussion
National Weather Service Marquette MI
350 PM EDT MON JUL 25 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...(Tuesday through Sunday)
Issued at 424 AM EDT MON JUL 25 2016

Tuesday through Wednesday night: A cold front is progged to sag
southward from Canada, Tuesday morning, into the Upper Great Lakes
Region Tuesday night as surface high pressure slides to the east.
Southerly flow on the back side of the high will help to increase
moisture into the area. This, along with forcing along and ahead of
the front, will provide chances of showers and thunderstorms for
most of the CWA through that time period. As the weak cold front
slides to the south of the area Wednesday and Wednesday night, the
better chances for showers and thunderstorms will also slide south
and linger over northern WI and possibly along the Upper MI/ WI
border. MUCAPE values are progged to be between 1000-1500 J/kg
Tuesday afternoon/evening and around 500-1000 J/kg Wednesday
afternoon/evening. The severe weather potential looks low at this
point, through this time period, as the system will lack any major
dynamical support, keeping shear values around or below 25-30 knots.
The storm mode would likely be more of a pulse thunderstorm mode
during the afternoon/evening hours on both Wednesday and Thursday.
Some of the the storms Tuesday afternoon/evening may pulse up and
become strong for a brief period of time, but organized severe
weather is not expected. 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 progged
to slide into the area from Canada by Thursday afternoon 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 slightly below normal for this time of year.
Normal highs are right around 77 while normal lows are around 55.
There is a 500mb shortwave that is progged to slide just south of
the U.P., mainly across WI, Thursday afternoon and evening. At this
point, the main impact for the U.P. would be an increase in cloud
cover along the WI border with perhaps a slight chance of showers
for the south half of the U.P.

Saturday through the extended: 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 couple shortwaves that slide across the area, bringing small
chances for showers and thunderstorms.  Exact details are tough to
pin down this far out, but it does look like the CWA could see
showers and thunderstorms, with the best chances occurring during
the afternoon hours each day through this time period. Confidence is
low enough at this point to stick with only low chance pops.

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 135 PM EDT MON JUL 25 2016

VFR conditions will prevail through the TAF period.

.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.

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


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