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Area Forecast Discussion (AFD)

Issued by Marquette, MI (MQT)

FXUS63 KMQT 150809

Area Forecast Discussion
National Weather Service Marquette MI
409 AM EDT Sun Sep 15 2019

.SHORT TERM...(Today and tonight)
Issued at 407 AM EDT SUN SEP 15 2019

Latest satellite imagery shows a shortwave moving through the upper 
Great Lakes region this morning, with the associated area of showers 
and a few thunderstorms also pushing E through northern Lake 
Michigan and the eastern U.P.  Zonal flow behind this feature will 
gradually amplify through the remainder of the weekend as a 5H ridge 
builds over the central U.S., leaving the area under a NW flow by 
Monday morning.

The shower activity will end over far eastern Upper Michigan this 
morning while a weak trough pushes through the area this 
afternoon. A few of the short term models are hinting at MUCAPES 
reaching toward 500 J/kg in the afternoon over the west, so having
a mention of a few showers in that area is warranted. Enough 
sunshine will be available today to push highs to around to 
slightly above normal.

For tonight, high pressure moving in will bring light winds and 
clearing skies. With plenty of antecedent moisture, expect fog to 
develop over much of the area, with locally dense fog possible where 
skies clear out completely over the western U.P. Over the east, some 
light precipitation will linger for a time with the passage of the 
trough, and with more cloud cover there, the fog won't be as 
widespread. Overnight lows will hold in the upper 40s to mid 50s.

.LONG TERM...(Monday through Saturday)
Issued at 400 AM EDT SUN SEP 15 2019

The late-summer warm up still looks on track for early/middle parts 
of the week, with temperatures pushing 10+ degrees above normal 
Monday/Tuesday, as upper-level ridging builds across the Upper 
Mississippi Valley/Great Lakes. Later this week, a few shortwaves 
cresting the upper-level ridge will work to flatten it out, and 
bring with it chances for precipitation. This pattern will favor a 
slight cool-down later in the week, but still expecting above-normal 
temperatures overall. 

Monday and Tuesday, as ridging builds into the region warm air 
advection will funnel 15-20+C air in aloft. Depending on how cloud 
cover and mixing evolves, it certainly isn't out of the question 
that we could see a few spots climb into the 80s, yes 80s! As 
longwave troughing gradually exits the western CONUS 
Tuesday/Wednesday, a lead shortwave may bring a slight chance for a 
few showers/rumbles of thunder out west late Tuesday into Wednesday. 
This initial shortwave will push the main ridge axis a bit further 
east on Wednesday, but overall southwest flow looks to prevail over 
the west half of Upper Michigan. This should keep any precipitation 
concerns out west through much of the day on Wednesday. Once the 
secondary shortwave lifts across the northern Plains, and low 
pressure wraps up into Canada, we should start to see the eastward 
push of the trailing cold front and increased chance for area-wide 
showers/storms Wednesday night into Thursday morning. 

Thursday through Friday, the NBM appears to be latching onto drier 
conditions associated with high pressure that will linger across the 
area. However, if the cold front stalls out over the Upper Great 
Lakes we could see some lingering chances for precipitation through 
the end of the week. Confidence in this occuring right now isn't 
high, but it certainly is a possibility. Next weekend, especially 
the latter half, looks like we could see more active weather across 
the Upper Great Lakes as another longwave trough and numerous 
embedded shortwaves rotate through the region.

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 120 AM EDT SUN SEP 15 2019

VFR conditions will prevail into early morning at all sites. Rain 
showers will move out this morning. Sun morning, expect a drop in 
cigs with LIFR developing at KSAW and MVFR at KCMX/KIWD. Fog may 
also develop. IWD will go back to VFR on Sun while SAW stays down in 
IFR/LIFR while CMX will go to MVFR Sun afternoon. All sites will be 
VFR Sun evening.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 407 AM EDT SUN SEP 15 2019

Light winds will dominate the area through the first half of the 
forecast period as high pressure settles into the area. Winds will 
remain below 20 knots through midweek, but gusty conditions to 
around 25 knots return to the eastern half of Lake Superior 
Wednesday afternoon. With the light winds and plenty of low level 
moisture, marine fog will be developing over much of Lake Superior 

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


LONG TERM...Ritzman