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National Weather Service Gaylord Michigan
1106 PM EDT Tuesday Sep 1 2015

issued at 1106 PM EDT Tuesday Sep 1 2015

High pressure remains fixed across much of the eastern Continental U.S. With
return flow of warmth and moisture (and instability) from the
plains into the western Great Lakes. Meanwhile...low pressure in
northern Quebec has a cold front stretching down through Ontario and
bisecting Lake Superior...then back through Wisconsin into
Minnesota. A couple waves along the just northeast of
Lake Superior spurring on line of showers/storms up that way.
Second wave is pushing into Minnesota and will be pushing through
northern Michigan later tomorrow.

Rest of tonight...should remain quiet and fairly mild (still 77 at
tvc at 11 PM...summer). Weak front will slip down into northern Michigan
but it seems with little fanfare. Given the warm/juicy airmass
out there suppose it/S not impossible we could see something
develop. But will maintain the dry forecast at this point.
Otherwise...recent observation starting to show some visibility reductions...and
we should see a fair amount of fog development through the balance
of the night.

Update issued at 816 PM EDT Tuesday Sep 1 2015

Bubbly cumulus has diminished quickly over the last few hours. Weak
front continues to slip east across central Upper Michigan...but
all precipitation along the front has pushed up into Ontario.
appears at least...that any shower/thunderstorm chances are minimal at
this juncture. Have thus removed from the forecast for the balance
of the evening.


Near term...(this evening through tonight)
issued at 331 PM EDT Tuesday Sep 1 2015

Warm and very humid out there this afternoon. Dew points spiked
into the lower 70s in most locales at midday...but have mixing out
a touch here at mid-afternoon. Temperatures are in the 80s...some 70s in
Mackinac and southeast Chippewa cos. Cumulus field is unimpressive across
northern lower/eastern Upper Michigan. More vigorous cumulus is seen in
eastern WI and the west half of Upper Michigan...where dew points are in
the low and even middle 70s in spots. However...shra/tsra are not yet
evident...outside of some weakening rain showers near the Keweenaw. These
are associated with a weakening cold front/wind shift boundary
crossing western/central Superior.

There is some potential for rain showers/thunderstorms and rain to increase in the vicinity
of S central Superior by early the incoming boundary
intercepts the instability plume (mlcapes to 2k j/kg) poking into
central Upper Michigan. Hi-res short term models are of mixed opinions
as to whether/how this will play out. NAM/NSSL-WRF favor bringing
convection into eastern Upper Michigan this evening. But most of these
are already bubbling of deep convection now...which is not
happening. Storm Prediction Center hrrr offers perhaps the most realistic solution...
generating convection north of MQT as the unstable plume lifts
over the Superior cold dome...then largely keeping it over The Big
Lake as it moves east. Was giving serious thought earlier to
boosting probability of precipitation...but looking at current conditions and model forecasts
have decided that can/T favor anything more than a 20 pop. Will
maintain that slight chance in western/central chip/Mack counties
through this evening.

Otherwise...another night with areas of fog. Perhaps not quite as
much as this morning (which was less than the morning
before)...thanks to strong mixing and resulting decrease in dew
points this afternoon. Still an unseasonably warm/sticky
night...with mins in the middle 60s to around 70f.


Short term...(wednesday through friday)
issued at 331 PM EDT Tuesday Sep 1 2015

Wednesday through Friday....the large area of high pressure which
has been in place across the eastern one third of the country...will
remain anchored over the middle Atlantic into the upcoming weekend. At
upper levels...a strong 500mb ridge anchored over the Gulf states and
Ohio Valley...will continue to nudge into the Great Lakes through
the forecast period. Middle level temperatures associated with this upper level
pattern will be well above normal across the Great Lakes into the
upcoming weekend...remaining around 16c/17c. This overall surface and
upper level pattern will continue Summer like weather...with well
above normal temperatures across northern Michigan through the end of the work week.

Will continue at least a partly sunny trend across the region as
model soundings and moisture forecasts show limited moisture through the
column...with 850/500mb relative humidity around 40/60 percent through the forecast period.
However enough low level moisture will be present to continue muggy conds
across northern Michigan...with surface dew points in the middle and upper 60s while middle
level dew points remain 12c or greater. Will continue with mainly dry
conditions across northern Michigan though a chance of precipitation exist Wednesday
afternoon and Thursday...the result of a weak ripple in the upper
flow. 850/500mb qvectors show significant enough convergence with
approaching 500mb trough Wednesday and Thursday to generate precipitation
across northern Michigan. Model soundings showing enough low and middle level moisture
(sfc dw points in the upper 60s) and instability (li around -4c, mu cape
between 2000 and 3000 j/kg, 850/500mb lapse rates increasing to 7
c/km) to mention thunderstorms Wednesday night and Thursday in the


Long term...(friday night through tuesday)
issued at 331 PM EDT Tuesday Sep 1 2015

Heat will continue to be the main story going into Labor Day...with
well above normal temperatures across the forecast area. A cold
front arriving early in the week will flatten out the 500 mb ridging and
return temperatures closer to...though still slightly above...normal
by the end of the extended period. There will be a small chance for
some scattered thunderstorms through the weekend...but as mentioned
by the previous shift...subsidence under the high pressure could
hold those off. The better chance for showers will be associated
with the early week cold front...which is still all over the place
as far as timing and placement.


Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 816 PM EDT Tuesday Sep 1 2015

Solid VFR conditions out there for the time being. But a fairly moist
boundary layer (sfc dewpoints up near 70) will lead to fog issues
later on tonight. That said...temperatures are still up near 80 in many
locations at it will take a few hours for temperatures to fall enough to
start seeing visibility reductions. So...have backed off timing of MVFR
visibilities by a few hours vs previous taf forecasts. Eventually...IFR
visibilities will probably materialize at some of the terminal sites
(pln/apn/mbl the most likely candidates).

Wednesday...morning fog will burn off by 14z. Another warm and
even more humid day in store for northern lower Michigan. This will
lead to afternoon thunderstorm possibilities. Most likely location looking
to be across NE lower Michigan and impacting the apn terminal
site. Have not explicitly included thunderstorm in the forecast yet...but
plan accordingly.


issued at 331 PM EDT Tuesday Sep 1 2015

SW winds will continue...around high pressure to our southeast. Winds
will be enough to keep the north end of Lake Michigan a little the 2-4 feet range...but short of advisory criteria.
Areas of marine fog/stratus will also continue...thanks to the
humid air in place.


Apx watches/warnings/advisories...


near term...jaz
short term...swr
long term...alm

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