Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 230921

Area Forecast Discussion
National Weather Service Marquette MI
521 AM EDT Sun Jul 23 2017

.SHORT TERM...(Today and tonight)
Issued at 520 AM EDT SUN JUL 23 2017

Strong shortwave is working across Upper Great Lakes early this
morning in NW flow aloft. Main sfc low pressure around 1006mb is
sliding across eastern half of Upper Michigan. Main area of showers
and some thunder is just ahead of the low in region of stronger
moisture flux convergence but otherwise there is only isold shra
back to the upper trough center over northeast MN. In wake of the
sfc low, cool and moist air with NW-N winds are resulting in stratus
and some fog from western to north central Upper Michigan. Main
focus for additional showers and storms will be ahead of the sfc low
early this morning, then mainly over the south and east this aftn as
the upper trough arrives there during peak heating. Could be enough
partial clearing to allow far scntrl and east closer to Lk Michigan
to reach low to mid 70s for highs today. These temps along with
lingering higher dwpnts in the 60s would result in MLcapes up to
1000 j/kg. Effective shear may reach over 30 kts so there is some
potential for isold stronger storms early to mid aftn. Farther west
and closer to Lk Superior increasing onshore flow and cold air
advection behind the low will result in temps staying in the 60s.
Gusty north winds will build waves enough to result in high swim
risk for the beaches of Marquette and Alger counties. Though temps
and wx is marginal, opted to issue beach hazard statement to
highlight the swim hazard.

Low clouds and some fog will linger through much of tonight for
areas favored by NE winds off Lk Superior. May be some light rain
and drizzle most of the night as well, especially north central.
Lows could fall into the 40s interior west if there is clearing.
Lows in the 50s elsewhere. Winds should gradually come down later
tonight as high pressure builds in.

.LONG TERM...(Monday through Saturday)
Issued at 312 AM EDT SUN JUL 23 2017

Overall, precipitation chances later this week look to be confined
to the middle of the week as a cold front pushes across the area.
Otherwise, high pressure will remain across the area and fair
weather will prevail.

Monday through Tuesday as upper-level ridging builds across the
Upper Great Lakes high pressure will linger with ample sunshine and
seasonable temperatures. By late on Tuesday afternoon and into the
overnight hours a potent shortwave trough is progged to track across
Manitoba, pushing a cold front across the Upper Great Lakes region.
This will allow showers and thunderstorms to push west to east
across Upper Michigan Tuesday night through a good portion of the
day on Wednesday. By late Wednesday, the front will push southeast
of the area and high pressure will begin to build across the region
once again. This post-frontal stable air mass will linger across the
area through the end of the week and possibly into the beginning of
the weekend.

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 137 AM EDT SUN JUL 23 2017

One area of showers and thunderstorms has exited the region while a
second continues to move through the west half of the Upper
Peninsula. This second batch of precipitation associated with better
upper level support from shortwave pushing through nrn MN at this
time. This feature continues forcing a weak front through the area
and will bring IFR/LIFR cigs with post boundary subsidence and high
low level moisture. Cigs to improve after sunrise but persistent
northeast flow should keep the cigs down at KSAW.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 520 AM EDT SUN JUL 23 2017

Low pressure crossing eastern Upper Michigan this morning and a cold
front settling north to south across Lk Superior will lead to winds
shifting from northwest to northeast over Lk Superior. Northeast
winds could then gust to 25 kts this aftn especially over western
and south central Lk Superior. Winds will gradually diminish tonight
into Monday as high pressure moves across. The next chance for
stronger winds from the south to southwest over 20 kts will be Tue
aftn into Wed morning over eastern sections as a low pressure trough
crosses the region. Otherwise, winds this week will be 20 kts or

Upper Michigan...
  Beach Hazards Statement from noon EDT today through this evening
     for MIZ005-006.

Lake Superior...
Lake Michigan...


LONG TERM...Ritzman
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