Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 190031

Area Forecast Discussion
National Weather Service Gaylord MI
731 PM EST Sat Feb 18 2017

.NEAR TERM...(Tonight and Sunday)
Issued at 307 PM EST Sat Feb 18 2017

...A touch cooler, but still well above normal...

High Impact Weather Potential: Nothing too significant. Need to be
on the lookout for some patchy dense fog tonight.

Pattern Synopsis/Forecast: Pacific airmass dominated environment
found across nearly the entire northern Conus, with temperatures
from the Northern Plains to southern New England running much above
normal. Rather zonal mid and upper level flow regime found across
these warm anomalies, with nearly cutoff low spinning into western
Tennessee and one high impact weather producing deep trough slicing
across southern California. Weak wave and attendant "cold" front
within the zonal portion of the pattern is now well to our east,
having crossed our area earlier this morning. As one can tell by
looking at temperatures, simply no legitimate shot of post-frontal
cold air advection behind this front, with mid-afternoon reading
well into the 40s and 50s (a good 20 or more degrees above normal
for today`s date!). Sun-filled skies definitely helped the
temperature cause, a rather rarity for this time of year when a
significant warm-up is underway.

Some changes heading through tonight and Sunday, as amplification of
the mid level pattern does force a shallow cool airmass south into
northern Michigan. Not only does this drop the temperatures back a
smidge, but when combined with added moisture from ongoing snowmelt,
also sets the stage for some overnight fog and stratus development.

Primary forecast concerns: Cloud/fog/temperature trends through

Details: That shallow cool airmass slowly makes its way into the
region tonight as ridge amplification occurs just to our west,
setting up a more northwest flavor to the low and mid level wind
fields. Area of stratus was observed well to our north with this
cooler environment last night, and with added moisture down here via
snowmelt, trends definitely support potential for stratus to
redevelop tonight across eastern upper and the northern reaches of
northern Lower. Moisture profiles look too shallow further south,
but cooling boundary layer does support some fog development. With
center of surface high remaining to our west, maintenance of weak
pressure gradient does support light winds, which should prevent fog
from getting too out of hand. Those light winds will also quell the
nocturnal temperature response some, but do expect most areas to
make a run to, or just below, freezing.

Very low confidence cloud forecast for Sunday, especially if
overnight status development does indeed occur. Surface high
pressure settles directly overhead through the day, really putting
the kibosh on any type of mechanical mixing. Of course, higher sun
angle may offset this some, just not sure to what degree. Like the
inherited idea of a slower stratus dissipation, perhaps taking much
of the day to break across eastern upper (that is assuming stratus
develops tonight, which in itself is far from certain). More
confident temperature forecast as shallower mixing and slightly
cooler airmass will result in readings at least a few degrees cooler
than those observed today. With that said, temperatures have been
overachieving across the region the last few days. With this in
mind, will side with the warmer end of the guidance spectrum, with
highs ranging from the upper 30s across eastern upper, and through
the 40s across northern lower.


.SHORT TERM...(Sunday night through Tuesday)
Issued at 307 PM EST Sat Feb 18 2017

...Rain and snow melt Monday night into Tuesday...

High Impact Weather Potential...

Pattern Synopsis/Forecast...As the 500 mb ridge moves into the Upper
Great Lakes, the 850 mb temperatures will be rising from roughly 4C
to about 5c at 12z/Mon. It looks like there could be some return
flow especially in the western part of the state, so temperatures
may slowly fall, or flatline through the night. The east side of the
state, the temperatures look to fall off from some decoupling, and
clearing skies. Through the day on Monday, however, temperatures
will zone off to the races again as the 850 mb temperatures rise to
around 9 or 10C by 00z/Tues. We are looking at some weak inversions
to somewhat mixed boundary layer during the day so would expect
temperatures in the lower to mid 50s, especially with the good
return flow. After 00z, we get a cold front passage that brings
train through about 2/3 of the state by 06z. Models have a timing
difference with the GFS having the rain out of the area by 18z. The
ECMWF still has rain over us until roughly 21z. so have an "average"
with low chance pops until 00z in NE Lower.

Primary Forecast Concerns...Rain doesn`t look that impressive, but
with the warm temperatures, and the relatively high dewpoints, we
could lose a lot of snow, with the rain. If this is the case, then
rapid river rises are possible, with minor flooding as well.

.LONG TERM...(Tuesday night through Saturday)
Issued at 307 PM EST Sat Feb 18 2017

The unseasonably warm temperatures continues into the day Wednesday
when record highs may be challenged once again. A cold front then
slips through later Wednesday into Wednesday night with cooler air
bleeding in behind it. Low pressure then follows for what looks like
Thursday night into Friday. This will likely lead to rain or snow,
depending upon the track which is way too early to call. Lake effect
snow showers will then be likely Friday into Saturday as a quick shot
of cold air moves in behind the departing low. Temperatures will
remain above normal through much of the period before settling down
to closer to normal by Saturday.


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 731 PM EST Sat Feb 18 2017

...Possible stratus issues late tonight into Sunday...

Cold front stretches across Ontario, slowly sagging down toward
the northern lakes region. Front will just glance the northern
part of the state late tonight into Sunday with shallow colder air
and possible stratus working into the the tip of the mitt and
impacting mainly PLN/APN. But, forecast confidence is not great
with this scenario. Have tentatively maintained VFR conditions at
all terminal sites through Sunday, but have a scattered lower
layer at PLN and APN.


Issued at 307 PM EST Sat Feb 18 2017

At times gusty winds this afternoon decrease in speed
tonight and Sunday as high pressure gradually builds overhead. Winds
turn more SE/south Monday and increase Monday night. Despite
increasing stability in warm advection, could see advisory level
winds during some of this period.




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