Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 192334

Area Forecast Discussion
National Weather Service Gaylord MI
734 PM EDT Wed Oct 19 2016

.SHORT TERM...(This evening and overnight)
Issued at 325 PM EDT Wed Oct 19 2016

Narrow ridge of high pressure overhead continues to slowly give way
to an approaching secondary cold front...which now extends from
Western Upper Michigan thru Central Wisconsin into Iowa. Scattered
diurnal CU has developed across most of our CWA this afternoon...and
combined with increasing upper level cloudiness...skies have become
partly sunny as temps warm into the 60s. Upper level clouds mark the
leading edge of increasing moisture well in advance of low pressure
developing over the Southern Plains moving NE toward the Ohio Valley.

Secondary cold front will slide thru our CWA tonight...and will
phase with the southern stream low as it moves into the Ohio Valley.
Low clouds along and behind the cold front will continue to press SE
into and thru our CWA tonight as mid/high clouds continue to
increase/lower/thicken along the northern edge of moisture from the
Ohio Valley system. Our far SE CWA near Saginaw Bay will be right
along the northern fringe of sufficiently deep moisture to warrant
any sort of POPs. In fact...still appears our entire CWA should
remain dry thru tonight as deeper moisture from the Ohio Valley low
stays south of our area...and deeper moisture and sufficiently cold
air for lake effect rain shower production stay just NW of Eastern
Upper Michigan. Both of these processes should begin to make some
progress into our far NW CWA and our far SE CWA on Thursday with
ongoing CAA behind the secondary cold front and as the northern edge
of deeper moisture from the Ohio Valley low edges into our far SE

Have only made some minor adjustments to POPs to better represent
latest short term model trends. Under mostly cloudy skies and
continued low level CAA tonight and Thursday...diurnal temp swings
will be rather small. Temps tonight will cool into the 40s...and
will only warm into the 50s on Thursday.

.LONG TERM...(Thursday through Wednesday)
Issued at 325 PM EDT Wed Oct 19 2016

Thursday night through Saturday...

Upper level trough continues to dig into the region Thursday night
into Friday with a general relaxation of the flow to weak
ridging/zonal on Saturday. Cold air advection will accompany the
trough while the rising heights will lead to warm air advection by
Saturday. It should be cold enough for at least scattered lake
effect rain showers in N/NNW flow favored areas for Thursday night
into Friday night before over lake instability wanes. Model
soundings have that inverted-v look (dry low level air) but as we
have seen over the first few early autumn events the models are
probably underdoing the over lake instability once again. It is even
marginally cold enough (850 mb temps of about -5 C) to think about
wet snowflakes mixing in (mainly across eastern upper) but will not
include any at this time due to continuity. Elsewhere, partly cloudy
and seasonably cool conditions are expected through this time
period. Lows in the 30s to lower 40s Thursday night and the upper
20s and 30s Friday night with highs in the middle 40s to around 50.


The 500mb pattern is just messy through the extended period...with
no real prominent set up locking in. After Saturday`s sharp trough
pulls east...the pattern flattens a bit for Sunday before it
amplifies with weak transient ridging out west and troughing over the
eastern third of the conus. Then it all shifts east into the mid-
week period. During this time, there will be a couple short waves
blast though providing shots at rainfall. So basically, what it all
spells out is alternating periods of dry conditions with periodic
`bouts of rain chances. Timing these pops will be the challenge
through the extended...and nearly a futile endeavor in such a
pattern that alters so quickly. So I`ll be looking to just line pops
up with the neighbors to provide a unified front and we`ll see how
things unfold in future runs. Temperatures during the period will
run real close to climo...with overnight lows a bit warmer than
seasonal norms on a couple of those nights.



.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 734 PM EDT Wed Oct 19 2016

MVFR cigs at times late tonight into Thu morning.

Secondary cold front will cross northern lower MI this evening.
Low cloud deck will eventually move in behind the front tonight,
mainly late. MVFR cigs expected for part of late tonight and Thu
morning. Slight chances for lake effect rain showers to develop,
but the best chance will be in upper MI.

Light northerly winds.


Issued at 325 PM EDT Wed Oct 19 2016

A secondary cold front dropping thru Michigan will phase with
developing low pressure lifting NE into the Ohio Valley. Colder air
filtering into the region behind the secondary cold front will
produce a few light lake effect rain showers Thursday into Friday.
In addition...our nearshore areas between Saginaw Bay and Thunder
Bay along Lake Huron will see small chances of light rain showers
along the northern edge of deeper moisture associated with the Ohio
Valley low. Winds and waves will remain below (sometimes just below)
SCA criteria thru Friday as these two systems impact our area.




LONG TERM...Sullivan/KAB
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