Area Forecast Discussion
Issued by NWS Gaylord, MI

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234
FXUS63 KAPX 260316
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1116 PM EDT Sat Mar 25 2017

.UPDATE...
Issued at 1007 PM EDT Sat Mar 25 2017

MRMS showing the downstate radars beginning to fill in a bit, with
the next round of rain pushing north. Was a little concerned for
the M-72 corridor, but the RAWS sites at Grayling, Mio and Barton
City, are showing the sfc temperatures and dewpoints rising to at
or above freezing. North of there is another matter, with the
temperature/dewpoint spreads of 2-4 degrees and the sfc
temperatures starting at or below freezing. That area will take
until almost 08z at least for the time being, before the sfc
temperatures rise above freezing. So the advisory for NE/NC Lower
looks good as the precipitation is just getting going.

E Upper still looks on track as sfc temperatures may be a 32 right
now, but the dewpoints are anywhere from 12 to 20F. so when it
starts to rain, temperatures will crash below freezing and stay
there until Sunday morning or so.

UPDATE Issued at 825 PM EDT Sat Mar 25 2017

Rain is pushing through the forecast area, but is running into low
level dry air. The reinforcing shot of moisture is along and
south of US-10, but will begin to cross into the forecast area
over the next few hours. This will begin to warm the lower levels
and keep the freezing rain north of roughly M-32. There may be
some small patches of freezing rain east of I-75 along and north
of M-72, but for the most part, it looks like the system will
force the warm air north with the rain. However, with the cool dry
air north of M-32, will continue to cool, and with lower dewpoints
in the mid-20s (PLN is 26F and PZQ is 25F) temperatures will stay
under freezing for a few hours, until the warm air is forced
north, probably closer to 05z or so. E Upper will be under the gun
as the sfc temperatures fall into the mid 20s before it start
raining, and it will take a lot longer to warm probably not until
sometime Sunday morning (around 15z).

&&

.NEAR TERM...(Tonight through Sunday)
Issued at 309 PM EDT Sat Mar 25 2017

...Significant ice accumulations expected across the north tonight...

High Impact Weather Potential...Widespread freezing rain across our
northern CWA causing hazardous travel conditions.

Pattern Synopsis/Forecast...Vertically stacked low pressure remains
centered over Missouri this afternoon with the associated warm front
extending eastward thru Central Illinois...Northern Indiana and
Northern Ohio. Elongated area of precip continues to fire north of
this warm front...with additional areas of precip ahead of and
around the low pressure system itself. Strong cold Canadian high
pressure has begun to swing NE into Quebec...allowing the warm
front...associated lift and deep moisture to surge northward toward
our CWA. Latest KAPX 88D base ref loop shows this resurgence of
moisture and precip already beginning to happen across our southern
CWA. All short term models still show POPs increasing to categorical
from SW to NE across our entire CWA tonight. Model soundings and
projected surface temp trends thru the night suggest precip should
remain all liquid for much of our southern CWA. Northern half of our
CWA however will likely receive mainly freezing rain and...in some
locations...significant ice accumulations especially across Eastern
Upper Michigan. Model soundings continue to show a very impressive
warm nose developing aloft...providing plenty of above freezing air
to completely melt the snowflakes aloft. Surface temps will hover
right around and/or just below freezing thru much of tonight and
into Sunday morning for locations along and north of M-32...with the
exception of Antrim county where temps should remain above freezing.

In coordination with MQT...will issue a strongly worded Winter Wx
Advisory for Eastern Upper Michigan with the expectation of up to a
quarter of an inch of ice accumulation is expected for later this
evening thru Sunday morning. Expected ice accumulation is notably
close to a quarter of an inch...above which is warning criteria.
Given the borderline nature of this evening (bordering on advisory
and warning criteria)...have decided to begin with a strongly worded
advisory and will watch/upgrade if necessary. Will also issue an
Advisory much of far Northern Lower Michigan along and north of M-32
for tonight where less than a quarter of an inch of ice accumulation
is expected as temps will likely warm above freezing in these areas
late tonight.

Once temps warm above freezing by afternoon across Eastern Upper
Michigan on Sunday...freezing precip will switch to all rain and any
ice accumulation should begin to thaw. High temps Sunday afternoon
will range from the mid to upper 30s in Eastern Upper Michigan to
the lower 50s across our far SW CWA.

&&

.SHORT TERM...(Sunday night through Tuesday)
Issued at 309 PM EDT Sat Mar 25 2017

...Wet wx into Sunday night then gradually drying out...

High impact weather potential...none.

Stacked low will lift out of MI Sunday night, with the 500mb
circulation opening up with time. Wraparound moisture will linger
into Monday morning, before a drying trend begins. A trailing
shortwave and associated surface low will move up the Ohio Valley
Monday night. Associated wx impacts will brush by to our south.
Considerable drying is expected after that, with a welcome stretch
of much quieter wx.

Sunday night...surface low advances ne-ward across lower MI, and
will be over northern Lake Huron by daybreak. Core of best dynamics
(dpva/height falls aloft) will be felt over the southern/eastern
Great Lakes. Still, we remain on the warm-advection side of the
system in the evening, with associated steepening lapse rates thanks
to falling heights/cooling aloft. Any outright cape seen in the Nam
stays just to our se, but certainly sct to perhaps nmrs showers will
be seen early on. SPC day 2 risk of thunder just clips se sections
of the forecast area; will refrain from adding thunder at this time
given lack of progged cape this far n/w. For overnight, wraparound/
cold conveyor belt band wraps into the region. But, this will be
diminishing with time as the 500mb low opens up and the 700mb low
center weakens. Sct to nmrs pops are again still in order, but
widespread precip is not a sure thing given the weakening system.
Weak cold advection will just be getting underway, and 850mb temps
will remain well above 0C. So precip will be all rain. Total QPF for
the night in most places will be less than a quarter-inch, but some
isolated higher amounts are certainly possible, especially in the
evening.

Min temps mid 30s to lower 40s.

Monday...initial surface low moves ne-ward from northern Lake Huron
into Quebec, though some troffing will linger over northern Huron.
Band of backwash moisture will exit northern MI during the morning,
and again this entire part of the system is weakening anyway as the
mid-level circulations weaken further. Hard to argue for anything
more than some chancy pops in the morning. Airmass remains quite
sludgy thru the day between 800 and 950mb, so anticipate a
considerable amount of cloud cover. Could perhaps even be some
patchy drizzle around, though model soundings do show some sub-950mb
dry air that would limit that potential. Next system will be
advancing into the mid-MS valley, with associated precip perhaps
reaching southern Lake MI. No risk of this getting up here this soon.

Max temps 40s to lower 50s.

Mon night/Tuesday...models are trending more confidently to the
idea that precip associated with the OH Valley system will pass to
our south. Arenac Co has the best chance at getting grazed with some
light rain Mon night, but a dry forecast is almost certainly best. A
Hudson Bay high will push somewhat cooler but much drier air into
the region by Tuesday, and cloud cover will finally wane. This trend
will start to play out late Mon night in eastern upper, with mostly
sunny skies expected across all of northern MI by Tue afternoon.

Min temps upper 20s to upper 30s. Max temps 40s to around 50f.

.LONG TERM...(Tuesday night through Saturday)
Issued at 309 PM EDT Sat Mar 25 2017

Quiet start to the extended with high pressure moving through the
area mid-week. Bit more uncertainty heading into the weekend
however; as most guidance is developing low pressure and propagating
it toward the Great Lakes over the weekend. The track of this is
pretty divergent right now though, ranging from a complete miss to
the center of the track across northern Michigan. I think the
extreme southern solutions are not as likely, and there is a notable
northward shift in them from the previous run. And given the favored
storm track this year has been right over us, I don`t think those
solutions are too far off. Normal temperatures for this time of year
are around the mid 40s, and highs through the extended look to be
right around that if not slightly above. So if precip does come, it
should come as rain during the day. Overnight lows continue to dip
low enough that snow mixing in isn`t out of the question if precip
lingers overnight. Consensus blends are livable for now given the
uncertainty, as it favors bringing precip in over the weekend. Will
watch for any southern adjustments with the system which would
necessitate a drier forecast.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1102 PM EDT Sat Mar 25 2017

Rain continues to move into the region with the radar filling in.
Main area of concern for icing based on the latest temperatures
will be along and north of the M-32 corridor, so PLN will be
freezing rain through a good portion for the night. APN is still
the question mark as the warmer air off of Lake Huron may keep
them above freezing through the night. TVC and MBL are above
freezing and so are their dewpoints, so will not expect any
freezing rain at those sites.

Otherwise the warm air will continue to push into the region
clearing the freezing rain out between 10z and 12z, and out of E
Upper between 15z and 18z.

&&

.MARINE...
Issued at 309 PM EDT Sat Mar 25 2017

Winds and waves will remain at and/or build to SCA criteria tonight
as the pressure gradient tightens along the northern periphery of
developing low pressure to our SW. Widespread precip will surge
northward thru Northern Michigan tonight into Sunday...with mainly
rain expected south of M-32 and mostly freezing rain expected north
of M-32.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY until 8 AM EDT Sunday for MIZ016>019-
     022>024.
     WINTER WEATHER ADVISORY until noon EDT Sunday for MIZ008-015.
LH...SMALL CRAFT ADVISORY until 7 PM EDT Sunday for LHZ345>349.
LM...SMALL CRAFT ADVISORY until 5 AM EDT Sunday for LMZ323-341-342-
     344>346.
LS...SMALL CRAFT ADVISORY until 2 PM EDT Sunday for LSZ321-322.
&&

$$

UPDATE...JSL
NEAR TERM...MLR
SHORT TERM...JZ
LONG TERM...ALM
AVIATION...JSL
MARINE...MLR



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