Area Forecast Discussion
Issued by NWS Gaylord, MI
FXUS63 KAPX 261758
Area Forecast Discussion
National Weather Service Gaylord MI
158 PM EDT SUN JUN 26 2016
Issued at 1133 AM EDT Sun Jun 26 2016
Morning surface analysis reveals occluded low pressure over
western Ontario and cold front arcing down through the Great
Lakes. Tough to exactly pick out the front, but it appears to be
draped down central upper MI and into eastern Wisconsin,
continuing through SW Wisconsin and into Iowa, with surface
dewpoints dropping off into the 50s behind that line.
Ahead of the front, rapidly decaying overnight thunderstorm complex
continues to roll through lower Michigan this morning, with the
northern extent sliding through northeast lower Michigan and some
spotty showers/drizzle over NW lower MI. Precip has and continues
to quickly diminish and all lightning has ceased across northern
lower MI at this point as SPC mesoanalysis shows any appreciable
instability resides well downstate and into the Ohio Valley. Lots
of cloud cover remains across the region along with some Lake
Michigan marine stratus/fog that has pushed into parts of eastern
upper and NW lower MI. But clearing line is making progress
through far eastern Wisconsin and through central upper MI.
Rest of today: Obviously our morning shower/thunderstorm complex
and cloud cover has and will put a damper on heating/destabilization
that we see today, although there will be a west to east clearing
trend this afternoon, and the days are long. So a bit of a race
between clearing/heating/destabilization and arrival of surface
front this afternoon. We may yet muster between 500 and 1500 J/KG
MLCAPE this afternoon (greatest across NE lower) if we can get
temps into the upper 70s to lower 80s. But...low level convergence
with the front itself is weak and main synoptic support for
ascent will reside well north into Canada. I still anticipate the
best shower/thunderstorm chances this afternoon will reside down
through southern lower MI into the Ohio Valley where much better
instability will be. However, one cannot rule out a few showers or
a thunderstorm popping up this afternoon, best chances across NE
Severe weather threat is also diminished. Weaker instability and
forecast 25 to 35 knot 0-6 KM bulk shear values is marginal at
best. Could see a beefier storm across NE lower, but severe threat
is looking limited and latest SPC day one outlook has taken the
marginal risk completely out of the CWA.
.SHORT TERM...(Today and tonight)
Issued at 322 AM EDT Sun Jun 26 2016
High impact weather potential: Isolated severe storm potential
today? Brief heavy rain rates.
Pattern synopsis/expected evolution: Rather strong mid level wave
continues to pivot east across south central Canada at this early
hour. Surface low tied to this wave moving into western Ontario,
with cold front extending south across western upper Michigan into
central Wisconsin. Well organized, albeit decaying, mcs making steady
east progress through the western Lakes, driven by lead charging
subtle wave overtopping veering lower level jet above axis of
moderate to strong instability. Whole pattern remains fairly
progressive today and tonight, with both main mid level wave and
surface low pivoting across central Ontario, with attendant cold
front crossing our area later this morning through early/mid
afternoon. Upstream moisture/instability axis will fold east in
response, hopefully setting the stage for some much needed rain for
at least parts of the area today.
Primary forecast concerns/challenges: Convective evolution,
including strength and coverage, today.
Details: Pattern recognition sure supports that which high res
guidance is drumming up...a decaying line (both in areal coverage
and intensity) of showers/embedded storms making a run at our area
this morning, followed by some (not much) hope for renewed convective
development this afternoon as cold front passes. Background synoptic
pattern also very supportive of this idea, with main deep layer
forcing passing by to our north, all-the-while core of deepest
instability gets shunted to our south. With all that said, steady
height falls through the day...collocated with some right entrance
region upper jet dynamics (a favored spot for convection)...both of
which align above axis of 1k-2k joules/kg of mucape along passing
morning/early afternoon cold front, definitely supports the
possibility of showers and thunderstorms today. As mentioned,
initial round of showers, with some embedded thunder, will come
through this morning tied to decaying upstream mcs (perhaps some
help from lift over Lake Michigan stable layer), with focus for
additional storms early this afternoon likely to occur across the
southeast third of the area where heating will be maximized ahead of
the front. Front looks to clear the area by mid/late afternoon,
ending the rain threat.
As for severe weather concerns: Latest day one SPC convective
outlook has nudged the marginal risk further southeast, the western
extent of which just clips parts of northeast lower Michigan. This
aligns nicely with expected best juxtaposition of 30 to 40 knot deep
layer shear and area of max surface based instability. However, even
here, lack of more impressive mid level support should keep any
severe storms isolated (if they form at all). Main threat will be
damaging winds, although can never rule out some isolated larger
hail if updrafts do become more organized. May see some rather
robust rainfall rates given pwat values up near 2 inches and wet
bulb freezing levels falling just short of 13k feet. Showers/storms
look to remain transient, negating any real significant rain totals.
Post-frontal drying is impressive later this afternoon and tonight,
bringing rapidly clearing skies. May see some clouds increase later
tonight across eastern upper Michigan as next wave approaches.
.LONG TERM...(Monday through Saturday)
Issued at 322 AM EDT Sun Jun 26 2016
Monday and Tuesday...can generally be summarized as cooling to below
normal readings through the period...with a few lingering
instability rain showers possible.
At the surface...the storm system which moved across Ontario during
the weekend will lift northeast into Quebec to begin the upcoming
work week...before a large area of high pressure from the northern
Plains settles into the Great Lakes Tuesday. At upper levels...
nearly zonal 500mb flow stretching from the Great Lakes to the west
coast on Sunday...will break down over the Great Lakes Monday as a
500mb trough digs into the region. Overall broad 500mb troughing
pattern will then linger over the Great Lakes and Ohio Valley into
midweek. The chances for pcpn during the period will be limited as
more stable air filters into the state to begin the workweek
(decreasing sfc and mid level moisture). Though have continued to
mention an isolated chance of rain showers over portions of lower
Michigan Monday evening. 00z-06z Tuesday...models show strong
convergence developing south of the Straits of Mackinac in advance
of 500mb trough sliding into the Great Lakes. This forcing will
combine with marginal lingering mid lvl moisture (850mb dew pts
around 10c) and developing cold pool aloft (500mb temps dropping to
-16c with 850/500mb lapse rates nearing 6c/km).
Much cooler daytime high temperatures can be expected over northern
Michigan to begin the work week...as 850mb temps in upper trough
fall from around 12c early Monday to around 6c Tuesday afternoon.
This pattern will generate temperatures in the 70s Monday...before
falling to below normal readings in the 60s Tuesday.
Wednesday through Saturday...generally seasonal temperatures with a
few chances of rain showers through the period.
Dry conditions are expected across the Great Lakes Wednesday as a
large area of high pressure lingers over the Ohio Valley. However
the chances for precipitation increase across the Great Lakes
Thursday and Friday...as a storm system organizes over Hudson Bay
and drops into Ontario.
At upper lvls...broad upper troughing over the eastern one third of
the country Wednesday...will sharpen into the weekend as a 500mb low
drops out of Hudson Bay and into Ontario by Friday. 850mb
temperatures in this pattern will be around 10c through the work
week...before slowly cooling to around 6c in sharpening upper
trough. This will generate nearly seasonal afternoon high
temperatures in the mid and upper 70s through Friday before cooling
into the lower 70s Saturday.
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 158 PM EDT Sun Jun 26 2016
Abundant MVFR cloud cover lingers across northern lower Michigan
this afternoon in the wake of earlier rainfall. Clearing line is
making it`s way across Lake Michigan and I still expect a west to
east clearing/thinning trend to the clouds over the next few hours
with CIGS becoming VFR. There remains a low probability for a few
showers/storms late this afternoon as a cold front slips through
the region. Low confidence and coverage and have not included in
any terminal forecasts with the 18Z issuance. But, best chance
will be at the APN terminal site.
Tonight, clearing skies and diminishing winds for most of the
night. Secondary/wrap around cloud cover associated with low
pressure over Ontario will be overspreading the region from the
north late, possibly getting into KPLN and KAPN toward morning.
In any event, daytime heating will lead to the development of
SCT-BKN CU by late morning and into the afternoon.
Some SW gustiness will persist this afternoon before diminishing
tonight. Winds veer more westerly with some gusts again on
Issued at 322 AM EDT Sun Jun 26 2016
Marginally gusty southwest winds today, likely peaking out
this morning and early afternoon during and shortly after cold
frontal passage. Still looks like borderline sca conditions on
northern Lake Michigan. Shower and thunderstorms will bring brief
gustier winds on all waters through today. Winds slowly swing around
more westerly tonight, becoming northwest on Monday. May see another
round of sca conditions on Monday.
LM...SMALL CRAFT ADVISORY until 11 PM EDT this evening for LMZ341-342-