Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 260128
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
928 PM EDT WED MAY 25 2016

.UPDATE...
Issued at 911 PM EDT Wed May 25 2016

First round of shower and storm action continues on, with next
pocket of scattered showers and embedded storms working back into
Wexford/Missaukee county areas. These showers are focused on a
frontal boundary laid out just south of M-55. In the meantime,
arcing band of showers and storms continued to weaken as they
worked their way eastward across eastern Wisconsin. Loss of
heating playing a role in the weakening process.

Gonna expect continued redevelopment of showers along and north of
the front too our south, while the broken band of showers/storms
to our west arrive in Manistee around 11pm-Midnight, a little
slower than earlier anticipated. Not expecting anything strong
from this round of precipitation. LLJ forcing not impressive and
weakens overnight. Can foresee less and less coverage with this
band of showers as it arrives. The parent shortwave and fairly
minimal MUCAPE leave much to be desired too. Regardless, there
will likely be some embedded non-severe storms.

Areas of fog are also likely tonight inland, where rainfall was
received. If we can clear out behind the rain overnight, some of
this fog could be rather dense.

&&

.SHORT TERM...(This evening and overnight)
Issued at 338 PM EDT Wed May 25 2016

High impact weather potential: Nothing too significant. Perhaps some
brief heavy rains and small hail within non-severe thunderstorms
this afternoon through Thursday.

Pattern synopsis/expected evolution: Warm and increasingly muggy
pattern found across the northern lakes this afternoon as upper
level ridge axis continues to dominate. Combination of increasing
moisture and those warm temperatures kicking off some scattered
showers and thunderstorms this afternoon, making it look and feel
even more like mid-summer. Southwest flow developing down through
the column, with the surface winds the last to respond as quasi-
stationary warm front has set up just to our south. Surface features
will eventually respond to stronger mid and upper level forcing,
eventually bowing that warm front north into our area by morning.
This front will attempt to mix further north Thursday, but per the
usual, cold lake waters will largely dictate how far north it
eventually makes it. Vicinity of this front and passage of mid level
support will bring additional chances for some much needed rain in
the coming days.

Primary forecast concerns/challenges: Addressing shower and
thunderstorm chances through the period.

Details: Diurnally driven scattered showers and thunderstorms will
will continue to propagate across the northern lower landscape the
remainder of this afternoon and early evening. "Greatest" coverage
expected to be south of M-32 and across interior areas where
convergence will be focused via terrain influences and lake breeze
fronts. Not expecting any severe weather given weak wind fields and
marginal instability, but slow propagation could result in some
locally heavy rains, and suppose some very small hail is possible.
Attention this evening and overnight turns to respectable surge of
theta-e advection in strengthening southwest flow regime (enhanced
by passing mid level wave). Broken band of showers should accompany
such, although honestly not very confident on exact timing and
coverage. Decent band of elevated instability, with upwards of 1k
j/kg 0-6km most unstable cape punching into southwest zones
overnight. So, thunder is certainly possible, but given depletion of
surface based instability and only marginal deep layer shear, feel
thunderstorm intensity should remain well below severe limits.

A rather soupy airmass (ok...by northern Michigan standards) spreads
across the area Thursday as that warm front slowly mixes north, with
dewpoints pushing the lower 60s. Not much of a deep trigger around,
with the front itself largely devoid of any mid level support.
Still, given progged ml cape development in excess of 1k joules/kg
(think NAM-WRF`s 2k+ is simply too high, based off its mid and upper
60 degree dewpoints), some convection should fire along the front
and any lake/elevation driven convergence maxima. No big severe
threat, although given better instability, any very well organized
updrafts may support some brief larger hail.

.LONG TERM...(Thursday through Wednesday)
Issued at 338 PM EDT Wed May 25 2016

Thursday night through Saturday...

Pattern synopsis/Expected evolution: Upper level ridging evident
across the middle of the country this afternoon will gradually push
east through the end of the work week leaving northern Michigan on
the eastern periphery of long wave troughing expected to settle into
the western two-thirds of the CONUS. Several shortwaves of interest
visible on water vapor imagery/upper level analysis with the first
arriving tonight into Thursday morning with several additional
pieces of energy expected to continue off-and-on precip chances
through the upcoming holiday weekend.

Forecast challenges:  PoPs/QPF/precip timing Friday through
Saturday.

Details: A fairly active period expected overall; however, little in
the way of concern at the start of the period (Thursday night) as it
stands now due to a pocket of low-mid level dry air expected to
rotate through the upper Great Lakes. However, more active
conditions are expected to arrive during the day Friday as one of
several shortwaves rotating in from the southwest is expected to
arrive during the late morning-early afternoon hours. Will gradually
increase PoPs/thunder chances from southwest to northeast during the
day Friday, becoming likely (but still in a scattered fashion) late
morning through the remainder of the afternoon hours. Severe weather
parameters look fairly anemic as a whole Friday-Friday night.
Despite 700-1500 J/kg of 0-1 km MLCAPE, bulk shear values under 30
kts will certainly inhibit any long-lived updrafts and limit the
overall severe threat. PWs surge upwards of 1.25-1.50+ inches
providing a heavy rain threat within any thunderstorms.

Precip chances continue Friday night into the day Saturday, both
synoptically driven from another shortwave or two rotating through
the Great Lakes and diurnally driven during the day Saturday. Once
again, just a very limited severe threat, but certainly the heavy
rain threat will continue in any scattered thunderstorms with
similar PWs as Friday, approaching 1.50 inches.

Above normal temperatures are expected to continue through the
period, ranging from the low-middle 70s along the immediate
lakeshores to the middle 80s in downsloping locations of
northeast Lower. Unseasonably mild overnight lows are expected
with temps 10- 15 degrees above normal, ranging from the upper 50s
north to middle 60s near Saginaw Bay.

Gillen

Extended (Sunday through Wednesday)...

The upper level trough will gradually dampen (fill in) through the
extended forecast period leaving a nearly zonal flow aloft. However,
there will be yet another upper level disturbance that will bring a
decent shot of showers and thunderstorms Sunday. There could be some
diurnally driven convection that pops during mainly Memorial Day
afternoon  (low chance pops). Only a slight chance for more activity
Tuesday followed by chance pops again next Wednesday with perhaps
another upper level disturbance. So overall, a little active but
nothing widespread or prolonged is expected. Humidity/dewpoints
slowly decreases through the period. It will remain very warm to
start the period then temperatures should settle back toward
climatology numbers for early June by the middle of next week.

Sullivan

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 742 PM EDT Wed May 25 2016

A band of showers and possible embedded thunderstorms will cross
the TAF sites starting at 04-05z at MBL and not until roughly
08-10z at APN. Cigs look to be relatively high based with just
some potential MVFR within stronger showers. Stratus could be an
issue late tonight, especially where it rains decently, which may
turn out to be PLN. Any stratus will mix out to a SCT-BKN deck of
cumulus as the day wears on, with likely some scattered showers
and storms developing on a frontal boundary expected to be laid
out over NRN lower Michigan. Looks to be a better shot at showers
at the airports compared to today. Light winds until mixing
Thursday for gusts 18-23 knots from the S/SW.


&&

.MARINE...
Issued at 338 PM EDT Wed May 25 2016

Rather light winds to continue for the foreseeable future as
stability remains high in an unseasonably warm airmass. Those same
conditions will continue to result in areas of fog, which at times
could be locally dense. Periods of showers and thunderstorms the
next several days, any of which could produce brief gusty winds.


&&

.APX Watches/Warnings/Advisories...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&

$$

UPDATE...Dickson
SHORT TERM...MSB
LONG TERM...Sullivan/Gillen
AVIATION...Dickson
MARINE...MSB



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