Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 181734

Area Forecast Discussion
National Weather Service Gaylord MI
134 PM EDT Mon Sep 18 2017

Issued at 1009 AM EDT Mon Sep 18 2017

No changes to that which was inherited. Cold front now well to our
southeast, with only a few lingering clouds holding on near
Saginaw Bay. Some shallow cumulus starting to develop across north
central lower Michigan, and would expect these to expand in
coverage through early this afternoon before partially mixing out.
May also see some increasing high clouds later today across
western areas. Expected highs in the 60s to middle 70s still
appears on target.


.NEAR TERM...(Today through Tonight)
Issued at 323 AM EDT Mon Sep 18 2017

...Morning fog/stratus/drizzle otherwise quiet...

High impact weather potential...none.

Cold front is departing across eastern Lake Huron. Trailing high
pressure is building into nw WI. The high will move slowly east
across northern Lake MI and eastern upper MI today. Weak warm
advection will resume tonight as the high lifts ne. A shortwave
and associated weak surface wave will approach the sw lakes late

Frontal band of mid/high clouds is also departing to the east. As
it does so, fog imagery is revealing some stratus left behind
over portions of northern lower MI. Radar (and walking outside)
indicates an area of associated drizzle over the high terrain of
northern lower. Much less in the way of low cloud cover to the nw,
indicative of the drier airmass trying to advect in. That and
diurnal heating will eventually erode and/or eject the stratus.
But this process may not finish until midday or even early
afternoon, especially down toward Saginaw Bay. Healthy amount of
sunshine for the rest of the day.

Mid and high clouds will spill back into region tonight, ahead of
the shortwave heading for the sw lakes. Plenty of dry air below 15k
ft though, so no chance for precip. Will be enough thin spots in the
cloud cover (especially early on) for respectable radiational
cooling, so temps will still see a healthy fall tonight.

Max temps today mainly within a few degrees of 70f. Min temps
tonight mid 40s to lower 50s.


.SHORT TERM...(Tuesday through Wednesday)
Issued at 323 AM EDT Mon Sep 18 2017

...Rain or Not?...

High Impact Weather Potential...Minimal as thunder threatens on
Wednesday/Wednesday night.

Pattern Synopsis/Forecast...After the frontal passage Sunday evening
and the resulting high building into the region on Monday, we get to
Tuesday when the previous model runs had precipitation trying to
sneak into the forecast area. It looks like now that the ECMWF and
GFS are relatively on the same page with the 500 mb ridge over the
region building more, and the sfc ridge over the region hanging
tough. Of course, the reason that the pattern is stopped up is Jose
and Maria as both are in areas that tend to slow down the pattern.
Which if you take a dprog/dt idea, then the rain and frontal passage
will hold off until Wednesday. Even then, the models have slowed the
precipitation down from Wednesday afternoon to Wednesday evening.
The SREF shows that there could be a shower or two on Tuesday, but
the better instability really looks better on Wednesday night with
the frontal passage.

Primary Forecast concerns...There is some thunder threat on
Wednesday afternoon, if you look at the SREF plumes, but the dynamic
kick to get things going looks to not be in the vicinity until the
evening. So will go with the rain at night.

.LONG TERM...(Wednesday night through Sunday)
Issued at 323 AM EDT Mon Sep 18 2017

...Above Normal and Relatively Precipitation Free Through the

Extended (Thursday through Sunday)...The front from Wednesday night
lingers into Thursday, and begins to stall, and even fades out,
leaving a bit of a "dirty" ridge overnight as the moisture rides the
return flow Thursday night. The GFS keeps trying to flatten the
ridge out (500 mb) and bring rain into E Upper, but the ECMWF pumps
up the ridge and keep us dry Friday through the weekend. The GFS is
a little slower with pumping up the ridge on Saturday and keeping
things dry through Sunday. Will go with the ECMWF for the time being
as it seems to be handling the Hurricanes a bit better, so think
that the ridge in the Upper Great Lakes will take hold sooner and
stay longer.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 133 PM EDT Mon Sep 18 2017

VFR conditions expected with just increasing high and mid level
clouds tonight into the early morning hours of Tuesday. Light
winds at all taf locations.


Issued at 323 AM EDT Mon Sep 18 2017

High pressure will slowly move over northern MI today, then move
to the ne tonight. Light winds will result thru tonight, with a
bit of an e to se wind on Tuesday. Marine headlines are not
expected, and the ongoing small craft advisory on Whitefish Bay
will be expired.




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