FXUS63 KAPX 261055

Area Forecast Discussion
National Weather Service Gaylord MI
655 AM EDT Wed Sep 26 2018

.NEAR TERM...(Today through Tonight)
Issued at 355 AM EDT Wed Sep 26 2018

...Much cooler with light lake effect rain showers...

High Impact Weather Potential...None expected.

Big airmass change from yesterday behind our surface cold front
which blew across the region earlier this morning. It will feel
brisk and much cooler today. Cool enough aloft (850 mb temps of
about +1 C) to produce a few lake effect streamers off of Lake
Michigan and Lake Superior through the morning hours. Surface
ridging poking in from the west may try to limit activity this
afternoon. Winds generally west northwest this morning will slowly
back into the west through the day then eventually southwest
tonight. Perhaps some lingering lake effect tonight in southwest
flow favored areas but moisture thins out so have backed pops down
to slight chance. Have also lowered max temps somewhat with a
range from the lower 50s north to the lower 60s southeast. Lows
tonight tricky due to cloud cover questions and whether winds
fully decouple but generally upper 30s to mid 40s expected.


.SHORT TERM...(Thursday through Friday)
Issued at 355 AM EDT Wed Sep 26 2018

...Cool, breezy, and showery...

High Impact Weather Potential...Low end gales possible on northern
Lake Michigan Thursday.

Pattern Synopsis/Forecast...As surface high pressure stretches out
over the Ohio Valley Wednesday night into Thursday, southwest return
flow will increase across northern Michigan. Weak isentropic lift
will develop out ahead of an approaching cold front. Low pressure
trekking through southern Ontario is progged to drag that cold front
through northern Michigan late Thursday night, exiting Saginaw Bay
shortly after daybreak Friday. Another blast of cooler air will be
the result, as 850mb temperatures fall below 0C by Friday evening.

Primary Forecast Concerns...Occasional shower chances and winds.

With the exception of eastern Upper and a portion of northwest
Lower, most areas will stay dry during the day Thursday while high
pressure sits to our south. Eventually upper troughing and weak
isentropic lift will win out, spreading shower chances into the
northwest 1/3 of the forecast area by mid afternoon. The actual
front will begin to move through late evening into the overnight,
bringing additional shower chances. Rainfall amounts will be higher
the farther north one goes, perhaps upwards of 0.25" over eastern
Upper. Winds will be the other main concern for Thursday as low
level warm air advection ramps up, with boundary layer mixing up to
~850mb. Winds will be strongest over eastern Upper and far northwest
Lower as a low level jet stretches from northern Lake Michigan to
Whitefish Bay, producing winds up to ~35 knots at 925mb and ~45
knots at 850mb Thursday afternoon. These areas may see gusts of 30
to 35 mph mixing down to the surface from late morning through mid

Additional pockets of weak mid-level energy will ripple through
behind the cold front on Friday, triggering some showers along with
possible lake enhancement. Forecast soundings show the low levels
progressively drying through the afternoon as diurnal mixing reaches
its peak, but expect plenty of residual cloud cover to linger. Not
as breezy as Thursday, but it will feel kind of raw with showers at
times and temperatures largely locked in the 50s thanks to the NW

.LONG TERM...(Friday night through Tuesday)
Issued at 355 AM EDT Wed Sep 26 2018

High Impact Weather Potential...Frost potential Friday and Saturday

Cool weather lies in store for the weekend as a broad upper trough
pivots over the Great Lakes region. Diminishing clouds late Friday
night may lead to some patchy inland frost as temperatures dip into
the mid to upper 30s. Surface high pressure will then pass overhead
Saturday into Saturday night. Combined with light winds, this will
be a more favorable setup for frost...however this potential looks
complicated by increasing mid level clouds, especially late. Current
forecast calls for widespread lows in the mid to upper 30s. Plenty
of model variance thereafter, but suffice it to say the pattern
looks unsettled and rather wet at times as a baroclinic zone lifts
into northern Michigan and interacts with PWATs climbing above 1"
through the first half of the work week.


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 638 AM EDT Wed Sep 26 2018

Over lake instability driven rain showers will be the rule today
into tonight...with rain showers in the vicinity at times at
MBl...TVC and eventually PLN with a westerly flow that becomes
west southwest tonight. Cigs will vary with mainly MVFR through
this morning eventually lifting to VFR. Winds will be gusty at
times today then diminish this evening.


Issued at 355 AM EDT Wed Sep 26 2018

Marginal small craft winds/waves expected across all nearshore
waters this morning with a gradual diminishing trend this
afternoon. Another round of gusty winds, reaching at least small
craft criteria, is possible on Thursday...primarily on Lake
Michigan where the gale watch is posted.


MI...BEACH HAZARDS STATEMENT through this evening for MIZ016-019>021-
LH...SMALL CRAFT ADVISORY until 8 PM EDT this evening for LHZ345>349.
GALE WATCH from Thursday morning through Thursday evening for
LM...SMALL CRAFT ADVISORY until 8 PM EDT this evening for LMZ323-341-
GALE WATCH from Thursday morning through Thursday evening for
LS...SMALL CRAFT ADVISORY until 8 PM EDT this evening for LSZ321-322.


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