Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 170819

Area Forecast Discussion
National Weather Service Gaylord MI
319 AM EST Fri Feb 17 2017

.NEAR TERM...(Today)
Issued at 318 AM EST Fri Feb 17 2017

High impact weather potential: None.

Pattern synopsis and forecast:

High amplitude synoptic pattern out there early this morning with
deep closed low pressure over Maine and ridging from the central
plains into central Canada. Shortwave energy was running into the
western edge of the upper ridging, resulting in sfc low pressure in
Saskatchewan. A stationary frontal zone extends south of this low
pressure into the central plains. Nrn Michigan lies in the forward
flank of the upper ridging in the tighter thermal gradient, with
deep low to mid level warm advection and associated mid and upper
level cloudiness overhead. Clearer skies were seen out underneath
the upper ridge.

The current shortwave energy will gradually flatten out the mid
level ridge as it slides in over nrn Michigan late this afternoon
and evening. Mid and upper level clouds will continue to
periodically cross the region, with perhaps some greater clearing
this evening under the ridge. Would think that additional higher
cloud arrives with the shortwave tonight, also seen on latest
satellite imagery, but fcst soundings are very dry. H8 temps will
rise dramatically to +12C into this evening, but as previous
discussion relayed, strong low level inversion and light-ish winds
will result in minimal mixing into that warmth aloft. Also, cold
lakes/snow covered ground will certainly do it`s own hampering of
reaching the total sfc warming potential. Regardless, can see upper
40s in and around the GTV Bay region where the greatest WAA and
least snow cover will reside, with the coldest reading in the Sault
in the lower half of the 30s. There could be a forecast issue of low
level stratus developing overnight, but many times this idea is a
bit too agressive, especially seeing as though the air mass is so
dry. We will be having snowmelt ongoing today, so maybe some the BL
could moisten up for some threat for developing stratus. Not gonna
bite too fully on that at this time. Would like to see higher
dewpoints (mid/upper 30s) before greater melting can lead to more
significant added BL moisture.

Would expect today to be a day when rivers and streams start getting
runoff from the melt, so water rises over the next few days can be


.SHORT TERM...(Tonight through Sunday)
Issued at 318 AM EST Fri Feb 17 2017

...Warming up for the weekend...

High Impact Weather Potential...None

Pattern Synopsis/Forecast...Quite an impressive warm pattern heading
into this late February weekend with models showing no subfreezing
850mb temperatures over the CONUS with the exception of the far
Northwest and Northeast. In zonal flow aloft, a weak shortwave will
move across eastern Upper Saturday morning accompanied by a weak
cold front. 850mb temperatures will then fall several degrees
through Sunday morning under the influence of CAA. Nevertheless,
this will not have a substantial negative impact on surface
temperatures, as 925mb and 850mb temperatures will still be reading
about 2 to 3 sigma above the mean across northern Michigan. The
zonal flow will quickly be replaced by upper level ridging Saturday
night through Sunday causing strong subsidence aloft, while high
pressure at the surface also drifts across the region keeping dry
weather in place.

Primary Forecast Concerns...With the mild temperatures in store for
this weekend and melting snowpack, naturally some may be wondering
if we`ll become locked in a low stratus and fog pattern like the
region saw with the last prolonged thaw in mid January. There will
likely be areas of fog that develop during the nighttime hours, but
at this time it`s not looking like persistent widespread fog that
will continue through the daytime hours as well. That being said,
NAM and GFS forecast soundings do develop a nearly saturated
boundary layer over eastern Upper and far northern Lower over the
weekend underneath the subsidence inversion. Think their low level
moisture is likely overdone, but this will have to be monitored as
it will of course impact temperatures. At this time highs Saturday
will range from the low 40s north to low 50s south...and a few
degrees cooler on Sunday. Can`t rule out some patchy drizzle that
develops thanks to onshore convergence around Whitefish Bay Saturday
night, as the NAM suggests.


.LONG TERM...(Sunday night through Thursday)
Issued at 318 AM EST Fri Feb 17 2017

High Impact Weather Potential...None

Heights continue to rise Sunday night into Monday as the upper level
ridge axis crosses northern Michigan. The mild stretch continues as
a result with temperatures still climbing in the 40s each day for
most of the area through Tuesday. The next weather maker will move
through the area Monday night into Tuesday, as rain accompanies a
potent shortwave and cold front. With good run-to-run consistency
and agreement between the ECMWF and GFS, have bumped up PoPs to
categorical Monday night through Tuesday morning. Far eastern Upper
may initially see a bit of freezing rain or snow Monday night as
temperatures fall into the low 30s there. Flow aloft then turns
mostly zonal with only weak disturbances moving through that could
trigger some isolated showers at times. Temperatures then drop a bit
towards the end of the work week behind a cold front that pushes
through Wednesday night.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1139 PM EST Thu Feb 16 2017

VFR conditions anticipated through the upcoming TAF forecast
period. Narrow band of mid/high level cloud cover will slide
through the region overnight into Friday bases
AOA 6K feet.

On Friday...VFR continues as warmer air noses into the region
through the day. Model guidance continues to suggest the
development of lower stratus/fog Friday night...the result of
warmer air/increasing dewpoints and snowmelt. Continue to believe
that guidance is a bit premature although some fog development may
occur Friday night for parts of northern lower Michigan. We may
indeed get into some stratus/fog issues heading into the weekend,
but only after warmer air/higher dewpoints get here.


Issued at 318 AM EST Fri Feb 17 2017

Increasingly stable conditions develop over the Great Lakes today
and into much of tonight due to strong warm advection. This will
keep winds under advisory levels until a cold front arrives Saturday
with conditions becoming more neutral with a tighter pressure
gradient. Advisory level winds much more possible then, and into
Saturday evening, but will hold off on any headlines at this point.
Lighter winds by Sunday with high pressure.




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