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FXUS63 KMQT 231130

Area Forecast Discussion
National Weather Service Marquette MI
630 AM EST Thu Nov 23 2017

.SHORT TERM...(Today and tonight)
Issued at 356 AM EST THU NOV 23 2017

No major weather impacts expected through the short-term portion of 
the forecast.

Today: A weak shortwave and weak surface trough sliding through 
the U.P. this morning will bring some light snow showers or 
flurries over the far eastern U.P., mainly east of Munising as 
winds become west to west-northwesterly. Otherwise, a surface 
ridge over the Mid-Mississippi Valley into the Ohio River Valley 
will link up with a weak ridge sliding southeast across Canada. 
This will place high pressure across the Upper Great Lakes 
throughout the day. This, along with drier air pushing into the 
area and warmer air aloft, will bring an end to the precipitation 
throughout the day. Cloud cover may linger over the Keweenaw 
Peninsula with continued upslope flow off Lake Superior. 850mb 
temperatures are progged to steadily warm; however, they should 
only warm to around -6C by 00Z/24, again, cool enough for 
continued cloud cover, but not cold enough for lake effect 
precipitation. Southern and central portions of the U.P. will 
likely see the sun sneak out throughout the day, allowing 
temperatures to warm into the mid to upper 30s, again, the cooler 
areas will be where cloud cover linger through the day, most 
notably over the Keweenaw. 

Tonight: The surface ridge will shift to the east allowing winds 
to become more southerly across the area. At the same time, low 
pressure will slide south and eastward into Ontario. This will 
allow a weak stationary front to lift north and eastward across 
the northern portions of Lake Superior as a warm front. This will 
be where the better moisture and forcing/isentropic upglide will 
be through the overnight hours. The warmer southerly flow on the 
back side of the front and behind the departing surface ridge will
allow temperatures to warm enough, both aloft and at the surface 
to keep the precipitation in the form of rain over Lake Superior. 
Most of the U.P. is expected to stay dry; however, cloud cover 
will steadily increase through the overnight hours. Overnight lows
will be in the upper 20s to low 30s.

.LONG TERM...(Friday through Wednesday)
Issued at 244 AM EST THU NOV 23 2017

Nam shows a shortwave in the northern plains 12z Fri that will move 
through the area Fri night. Nam brings in some deeper moisture and 
850-500 mb q-vector convergence across the area on Fri and both move 
out Fri night. Did not make too many changes to the going forecast 

In the extended, GFS and ECMWF show a 500 mb ridge across the 
Rockies with a trough off the west coast and another in New England 
12z Sun. The ridge moves into the plains 12z Mon. GFS then shows a 
trough moving into the upper Great Lakes 12z Tue with cold air while 
the ECMWF is slower with the trough by keeping it in the Rockies. 
The GFS continues to move things through with a brief cold spell on 
Wed while the ECMWF continues to lag behind and waits until Thu to 
bring in the colder air. Looks like the manual progs have followed 
the GFS solution closely with a brief shot of cold air Tue into Wed. 
Temperatures will be at or above normal for this forecast period.

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 630 AM EST THU NOV 23 2017

Cigs will raise MVFR at KCMX amd IWD this morning to VFR this 
afternoon. Otherwise expect expect VFR conditions throughout the 
forecast period at KIWD and KSAW. LLWS is expected to develop late 
this evening into the overnight hours as a low-level wind max noses 
in from the west. the next chance at lowering ceilings will be 
toward the very end of the TAF period as a cold front approaches 
from the west.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 356 AM EST THU NOV 23 2017

West to west northwest winds of 15 to 25 knots will back to the 
south late tonight into Friday at 20 to 30 knots with gale force 
gusts to 35 knots expected. This has led to the issuance of a gale 
warning from late tonight into Friday afternoon for most of Lake 
Superior. On the back side of the strong low pressure system 
additional gales of 35 to 40 knots are possible on colder northwest 
flow into the area for Friday night into Saturday. Winds are then
expected to remain in the 20 to 30 knot range through at least mid

Upper Michigan...
Lake Superior...
  Gale Warning from 7 AM Friday to 5 AM EST Saturday for 

  Gale Warning from 5 AM EST /4 AM CST/ Friday to 1 AM EST 
     /midnight CST/ Saturday for LSZ240>245-263-264.

Lake Michigan...
  Gale Warning from 4 AM to 4 PM EST Friday for LMZ221-248-250.



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