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fxus63 kapx 190057 

Area forecast discussion
National Weather Service Gaylord Michigan
857 PM EDT Wed Sep 18 2019

issued at 850 PM EDT Wed Sep 18 2019

Quiet evening out there, with only a few passing high clouds to
filter out the stars. Moisture advection continues just upstream,
as evident by narrow Theta-E ridge bowing north across central
Wisconsin into central Upper Michigan. Corridor of elevated cape
within this plume, with latest Storm Prediction Center mesoanalysis showing in excess
of a 1k joules/kg of most unstable cape. Not seeing any evidence
of convection yet, but all high res guidance develops some in this
axis as low level jet develops. Expect this corridor of showers
and isolated thunderstorms to slowly sag east, reaching western
sections of eastern Upper Michigan by very late tonight. Dry and
mild elsewhere, with lows ranging through the 50s into the lower


Near term...(through tonight)
issued at 303 PM EDT Wed Sep 18 2019

High impact weather potential: minimal thunderstorm chances late
across western portions of Chippewa/Mackinac counties.

Pattern synopsis/forecast: 17z surface analysis shows a 997mb low
over southeast Manitoba...with a cold front trailing south across
far western Minnesota/far northwest Iowa/southeast Nebraska. High
pressure over southern Quebec and New England ridges back into lower
Michigan. Upper level ridge axis roughly northeast-southwest across
the upper lakes...while a compact short wave trough/dynamic pv
anomaly spinning northeast across southeast Manitoba. Sunny skies
across northern Michigan at mid afternoon.

Upstream cold front will make slow progress across the upper Midwest
tonight...wind shift will be weakening as front tries to progress
into western upper/western Wisconsin overnight. Support short wave
energy expected to remain north of Lake Superior overnight.

Primary forecast concerns: precipitation threat tonight as cold
front slowly moves into the upper lakes. Band of precipitation had
been progressing across the upper Midwest during the day...but the
northern end has been thinning out with active convection now
confined to Iowa. Narrow area of clearing has developed behind this
area of precipitation along the front across western portions of
Minnesota/ potential for another line of convection to fire
during the late afternoon/early evening hours. Narrow Theta-E ridge
and instability axis expected to slowly advance east ahead of the
front...some of this edges into eastern upper late tonight which
will be the area most likely to see precipitation toward morning.
Will have a sharp pop gradient across eastern upper keeping rain
chances out of the southeast Chippewa County zone. Not expecting
much precipitation to reach northwest lower until Thursday morning.
Should be enough of a breeze overnight to prevent another night of
fog development.


Short term...(thursday through saturday)
issued at 303 PM EDT Wed Sep 18 2019

..unseasonably warm with slowly increasing shower chances...

High impact weather...none is expected.

Primary forecast concerns...pops through the period.

The upper level ridge parked across the region remains pretty much
in place through Friday before weakening and pushing slowly off to
the east this weekend. This setup should ensure well above normal
temperatures to continue. However, there are a couple of features to
keep an eye on. The first is a trough moving by to our north across
south central Canada. This feature will drag a weak cold front
toward the region. However, with the ridge in place it will have a
hard time making much progress. Generally will continue with chance
pops across eastern upper Thursday then just slight chance pops
Friday as the front slowly washes out. A trough currently across the
Pacific northwest will then bring somewhat better chances for
showers on Saturday.

Temperatures will remain well above normal through the period.

Long term...(saturday night through wednesday)
issued at 303 PM EDT Wed Sep 18 2019

High impact weather...none is expected.

A trough moving by to the north and an associated weak cold front
will bring decent chances for showers Saturday night into Sunday
night. Ridging should then end the shower chance Monday and hold
through Tuesday. Another trough will bring additional shower chances
Wednesday. Temperatures will cool off a bit as compared to the
recent unseasonable warmth but still be near to slightly above
normal through the period.


Aviation...(for the 00z tafs through 00z Thursday evening)
issued at 841 PM EDT Wed Sep 18 2019

Only concern tonight is the expected development of wind shear as
a low level jet spreads overhead. Only passing high clouds
expected, with any lower cigs expected to remain to our north and
west. Wind shear is expected to diminish Thursday morning.


issued at 303 PM EDT Wed Sep 18 2019

Marginal small craft conditions expected tonight on Lake Michigan...
will maintain ongoing Small Craft Advisory for the Lake Michigan
nearshore zones but will remove Grand Traverse Bay. Winds will
remain rather persistently out of the south and southwest right
on into the weekend.


Apx watches/warnings/advisories...
Lm...Small Craft Advisory until noon EDT Thursday for lmz341-342-


near term...jpb

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