Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 231730
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1230 PM EST Fri Feb 23 2018

.UPDATE...
Issued at 1103 AM EST Fri Feb 23 2018

Fast moving area of mixed precipitation will exit off to
the northeast shortly. Much of northern lower is now above freezing,
negating any lingering freezing rain issues, and the heaviest
snow/sleet mixture is now northeast of eastern upper Michigan. Have
gone ahead and expired/cancelled all winter weather headlines. Rest
of today will feature plenty of clouds and perhaps some patchy
drizzle/flurries, especially across the northern third of the area.
Temperatures will continue to slowly warm, reaching well into the
30s and lower 40s for this afternoon.

&&

.NEAR TERM...(Today through Tonight)
Issued at 328 AM EST Fri Feb 23 2018

...Wintry mix today...

High impact weather potential: Small accumulations of ice/sleet/
snow, impacting travel. Snow accums a little higher in parts of
eastern upper MI.

A prominent shortwave is lifting across the northern plains this
morning, with a few weaker impulses embedded within the broad sw
flow aloft. At the surface, pressures were lowering in a broad
swath over and just w of the MS River. Cyclogenesis will proceed
today, with organizing low pressure lifting across eastern upper
MI early this afternoon. Deeper moisture will be present this
morning, but not for terribly long, with dry slotting prevailing
across northern MI by early afternoon. Convection and heavier
precip rates will be down in the OH Valley, while better dynamics
will skirt by to our nw. That should result in wintry precip
today, mainly early.

Radar returns starting to blossom over far northern Lake MI and
environs. That far north and this early in the event, that would
fall as snow. However, low level dry air in northern areas will hold
back widespread precip for a couple more hours. We`ve also seen a
few sprinkles in the MBL area. Areas of precip extend back to
eastern MN/IA, and will lift quickly ne across northern MI this
morning. Dynamics will overall be on the increase as the system
approaches and deepens. But, as mentioned above, best dynamics will
be left of the surface low path, to our nw. And deep convection in
the OH Valley will hinder northward moisture transport. Anticipate
overall QPF of around 0.30" in much of eastern upper MI, dwindling
to 0.10" or a bit less, near and se of a TVC-Rogers City line.

The quick surge in warm/moist advection that produces this precip
event, will also produce rapid changes in our thermal fields, and
thus p-type. One very important trend noted in the near-term
guidance over the last 12-18hrs is to slow down precip onset. That
will allow some critical extra time for warm advection at the
surface to work.

For northern lower MI, the near-term guidance keeps the bulk of the
precip as rain. Some snow will be seen early on near and north of
M-68, with perhaps an inch of snow up by the bridge. Sleet may
mix in relatively early on, but otherwise liquid precip or a rapid
transition to such will prevail. Guidance also quickly takes
surface temps above freezing early today. There is a window for
freezing precip across a good portion of northern lower MI up thru
9 am, but after that it`s just rain. The above keeps progged ice
accums small; less than a tenth of an inch, particularly over the
higher terrain of n central lower MI. Of course, it doesn`t take
much ice to cause travel problems. In general the winter wx advis
in northern lower MI looks OK, though will be watching ob trends
to see if it`s safe to cancel some coastal counties on both sides
of the peninsula early this morning. MBL was 34/16 about 90 min
ago (that`s plenty of evap cooling potential), and even the
present 33/24 leaves the window open for some early freezing
precip. But we are trending toward closing that window quickly.
(Thanks to GRR for the coord this morning.)

Eastern upper MI will see more QPF, and will stay as snow longer
before transitioning to PL/FZRA/RA almost just as precip tapers off.
Southern portions will see a longer period of mixed precip, lowering
snow-liquid ratios. Snow totals will range from around an inch at
St Igance and Drummond Isl, to 3-4" for Paradise and Whitefish Pt.
Just a touch of glaze (less than 0.05") will fall in spots. Again,
the advisory up here is fine.

Though deeper moisture is long gone after noon-1 pm, the low levels
will be soupier longer. This is especially the case in eastern upper
MI, where the surface-based moist layer will extend up to 6k ft (vs
3k ft at places like TVC and GLR). That will keep chances for a
drizzly light rain in the Straits area and points north this
afternoon. This could then migrate a bit south into far northern
lower MI this evening (as chance for sprinkles and flurries,
primarily), before we finally see that moist layer get increasingly
shallow. By morning, high pressure will be moving overhead. We might
be prone to seeing some fog overnight in places that partially
clear, though a still moist 2-3k ft layer makes that a somewhat
uncertain proposition. For now, will have most places become partly
cloudy overnight.

Max temps today in the mid 30s to lower 40s. Min temps tonight
around 20f to the mid 20s.

&&

.SHORT TERM...(Saturday through Sunday)
Issued at 328 AM EST Fri Feb 23 2018

...Wintry mix likely Saturday night; Windy Sunday...

High Impact Weather Potential: Another round of messy wintry weather
expected across parts of northern Michigan Saturday night into early
Sunday.

Pattern Forecast: Focus will revolve around a well-defined shortwave
emerging from the Rockies Saturday morning with an attendant
developing area of low pressure set to trek from the southern plains
northeastward through WI into the Upper Peninsula by Sunday
morning. As a result locally, another round of messy wintry weather
is anticipated Saturday night into early Sunday as isentropically
driven precip spreads southwest to northeast across the forecast
area.

Primary Forecast Concerns/Challenges: Precip-types and amounts
Saturday night. Gusty winds Sunday.

A rather tranquil start to the forecast period during the daylight
hours Saturday with above normal high temperatures under partly
sunny skies. However, by Saturday evening, east-southeasterly winds
will gradually become gusty (25-30 mph) along with an increasing/
lowering cloud deck ahead of the aforementioned area of low pressure
set to spread precip southwest to northeast across the area as early
as 11 PM - 2 AM across much of the area. Main concerns revolve
around precip-type and the potential for slippery roadways and
hazardous travel. Expectation is for precip to initially briefly
fall in the form of snow and/or sleet, transitioning fairly quickly
to a messy wintry mix, including freezing rain, before becoming all
rain across much of the forecast area by sunrise Sunday as a
nocturnal temperature should be evident. Greatest threat for
potentially impactful ice accumulation will be found across interior
northern lower and potentially all of eastern upper. Current trends
suggest somewhat lesser ice amounts than 12 or 24 hours
ago...generally a tenth of an inch or less over the entire area.

Steadiest precip quickly becomes ushered north Sunday morning with
many locations dry by the afternoon hours. Climbing temps Sunday
afternoon (highs in the upper 30s-low 40s) will help to alleviate
any additional icing concerns, but none the less, the Saturday night
period will likely feature hazardous travel across at least part of
the region. Will hold off on any headline decisions with this
morning`s headlines still in effect.

Otherwise, the next concern is short to follow with Saturday night`s
gustiness increasing further as the pressure gradient strengthens on
the back side of departing low pressure during the day Sunday. Wind
gusts approaching 35-45 mph across much of the area (highest near
the Great Lakes shorelines) will raise concern for power outages,
especially in any locations with ice covered power lines and/or tree
branches from ice accumulation Saturday night.

.LONG TERM...(Sunday night through Thursday)
Issued at 328 AM EST Fri Feb 23 2018

High Impact Weather Potential: Minimal.

A fairly quiet start to next week is anticipated with northern
Michigan sitting on the northern periphery of sprawling high
pressure anchored over the southern tier of the CONUS through
Tuesday. The next threat for widespread precip arrives
Wednesday...continuing potentially into Thursday, although the
details remain far from certain at this juncture.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1228 PM EST Fri Feb 23 2018

IFR and MVFR producing low overcast and mist/drizzle will
gradually scatter out this afternoon and early evening, leaving
behind just some passing high and mid level clouds overnight into
Saturday morning. Light winds through the taf period.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
&&

$$

UPDATE...MSB
NEAR TERM...JZ
SHORT TERM...MG
LONG TERM...MG
AVIATION...MB



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