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fxus63 kapx 211410 cca 

Area forecast discussion...corrected
National Weather Service Gaylord Michigan
1010 am EDT Sat Sep 21 2019

issued at 1010 am EDT Sat Sep 21 2019

Patchy fog has largely lifted in northern lower Michigan. Fog was more
extensive in eastern Upper Michigan and is still eroding, but vsbys are
drifting higher at the twin saults even though a low overcast
persists. Clouds and fog will continue to gradually erode in
eastern upper, but did have to stretch out fog mention deeper into
the morning.

Have added some timing details to afternoon/early evening precip
chances. Cams support a chance for showers (and perhaps a T-storm)
in NW lower Michigan as soon as mid-afternoon. Those expand NE-Ward in
time, toward The Straits area by late afternoon, and across all
of northern Michigan by early evening.

Temps are already jumping nicely in NW lower mi, where there is
less cloud cover than elsewhere. Frankfort is 76, cad 75. Though
developing cu will help slow that temp rise, will boost temps a
smidge in NW lower.


Near term...(today through tonight)
issued at 229 am EDT Sat Sep 21 2019

..increasing chances of showers and storms thru tonight...

High impact weather potential...minimal. Slight chance of
thunderstorms this afternoon and tonight. Severe storms are not

Pattern synopsis/forecast...large area of high pressure remains
centered along the eastern third of the US early this morning.
Meanwhile...a stationary front is holding over Upper Michigan
attached to developing low pressure over the northern plains.
Several areas of convection are impacting upstream locations over
the northern plains attm. Meanwhile...mainly clear skies and dry wx
is holding over the western Great Lakes as temps cool thru the 60s
and into the 50s.

As we head into today and tonight...southerly low level winds will
strengthen in between departing high pressure and an approaching
upstream cold front. Clouds and chances of showers will steadily
increase beginning this afternoon and continuing thru tonight as
deep Gulf moisture...likely with some enhancement from tropical
storm Imelda...surges into Michigan. Instability will be limited and
the potential for strong/severe storms is very small...but there
certainly is the potential for heavy rain given the availability of
deep moisture and the slow eastward progression of the front. Will
maintain chance pops this afternoon increasing to likely/categorical
pops tonight...with a slight chance of thunder throughout this time.

Expect another warm and humid day across the Northwoods despite
increasing cloud cover thanks to strengthening warm air advection ahead of the cold
front. Afternoon highs will range from the mid to upper 70s across
eastern Upper Michigan to the low to mid 80s for all of northern
lower Michigan. Cold frontal passage will hold off until mild and
muggy conditions will persist into tonight. Overnight lows will be
in the low to mid 60s.


Short term...(sunday through monday)
issued at 231 am EDT Sat Sep 21 2019

..showery and cooler...

High impact weather potential: minimal

Pattern/synopsis: current ridging over the Great Lakes starts to
shift east on Saturday. By early Sunday we'll be dealing with an
elongated shortwave crossing the upper Mississippi Valley. This
wave will be supporting a low pressure system moving north through
Ontario before it slides east over James Bay on Sunday. Through the
day Sunday the prefrontal trough crosses the area, with cooler and
drier air trying to work in behind it. Ahead of this feature plenty
of warm moist air will remain, with pwats aoa 1.75". This is 2 to 3
St. Dev above the mean for late September. This will be working with
pockets of 40+ kt bulk shear, but this will be intermittent, and
better shear won't work its way into the area until overnight. By
this time the main slug of moisture will have already moved off to
the southeast. There will also be very little instability which
wanes through the day. With the strong to severe storm threat very
limited, the main threat will be heavy rain and lightning. While
showers and rumbles of thunder are possible throughout the day, the
heaviest round of rain should be underway early Sunday morning with
the initial surface front/trough. Guidance still has about quantitative precipitation forecast
ranging from around 0.5" in ern upper to over 1.0" in the southwest
by the time most of the rain ends early Monday morning. And wpc has
kept US in a marginal risk for excessive rainfall for Sunday.
Through the night the main front crosses the area, keeping good
soaking rain chances going though at least the morning. Lingering
morning showers will be aided by wrap-around moisture as the system
pulls off to the east. Drier air works its way into the region
Monday as surface high pressure slides to our south.

Thick cloud cover and wide spread rain will limit diurnal heating on
Sunday quite a bit, with highs a good 10 degrees cooler than on
Friday. With the new airmass ushered in with this system and
continued light caa, highs finally drop to near normal Monday.

Long term...(monday night through friday)
issued at 231 am EDT Sat Sep 21 2019

High impact weather potential: minimal

The pattern becomes more progressive through midweek, with quick
shortwave ridging passing overhead on Tuesday. This gives way to
elongated troughing rotating through southern Canada Wednesday and
Thursday. As a piece of this energy rotates over Lake Superior into
southern Ontario it will drag a front across Michigan late Wednesday
into Thursday. Friday may dry out again as heights once again build
back over the eastern third of the country. Temperatures remain near
to slightly above normal for the week.


Aviation...(for the 12z tafs through 12z Sunday morning)
issued at 645 am EDT Sat Sep 21 2019

A cold front currently located over the northern plains will
slowly push east into the western Great Lakes region over the next
24 hours. Showers and a few embedded thunderstorms will develop
along and ahead of this front...impacting all northern lower
Michigan taf sites this afternoon and tonight. Residual early
morning fog and resulting IFR conditions will quickly dissipate
and improve to VFR once daytime mixing begins after sunrise.
Conditions will deteriorate to MVFR and possibly IFR tonight as
deep moisture surges northward into the region...kicking off
widespread showers and a few thunderstorms. Southerly winds will
strengthen ahead of this front...gusting to 15 to 25 kts this
afternoon and tonight.


issued at 231 am EDT Sat Sep 21 2019

Winds and waves will reach Small Craft Advisory criteria within all of our nearshore
areas today...tonight and into Sunday as southerly winds strengthen
ahead of an approaching cold front. Chances of showers and
thunderstorms will increase this afternoon and especially tonight
into Sunday as deep moisture surges northward ahead of this front.


Apx watches/warnings/advisories...
LH...Small Craft Advisory from 8 PM this evening to 8 PM EDT Sunday
for lhz345>349.
Lm...Small Craft Advisory until 8 PM EDT Sunday for lmz323-341-342-
Ls...Small Craft Advisory from 8 PM this evening to 8 PM EDT Sunday
for lsz321-322.



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