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000 
FXUS63 KAPX 252012
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
312 PM EST Sat Feb 25 2017

.NEAR TERM...(Tonight and Sunday)
Issued at 308 PM EST Sat Feb 25 2017

... Much more typical late winter northern Michigan weather...

High Impact Weather Potential: Not much. Still looking at some minor 
snow accumulations into this evening and again on Sunday.
  
Pattern Synopsis/Forecast: Cold has definitely returned to the north 
woods on the heels of gusty northwest winds on backside of departing 
shortwave trough. Earlier system driven widespread light snow 
continues to transition to more of the lake effect variety as this 
cold air travels over the almost completely unfrozen Great Lakes. 
Combination of low inversion heights and strong diurnal disruption 
has definitely kept snow accumulations in check, even in the most 
persistent activity. Next wave within developing broad northern 
Conus troughing already racing east into the northern Plains, 
setting its sites on our area for Sunday.

Primary forecast concerns: Additional snow accumulations into this 
evening and again on Sunday.

Details: Northwest flow lake snows look to continue into this 
evening, slowly diminishing in intensity as synoptic moisture 
contribution is lost and already low inversion heights lower 
further. Could see another inch or so in most persistent activity. 
Given gusty winds which are likely producing some blowing/drifting 
snow in those typical exposed areas, will simply let inherited 
advisory ride for at least a few more hours. Dry air and lowering 
inversion heights should really put a damper on lake snows 
overnight, especially off of Lake Michigan. Somewhat more favorable 
lake snow parameters persist a touch longer across the snow belts of 
eastern Upper. Next wave and slug of deeper moisture arrives Sunday. 
Forcing is limited, and the best of what there is passes by to our 
north. Just enough there to produce some light snow showers, 
particularly across eastern upper Michigan. Wildcard remains 
possible lake contributions, with marginally cold enough low level 
thermal profiles in increasingly gusty southwest winds. Not 
expecting much as inversion levels remain low, but still think an 
inch or two of new snow remains reasonable across eastern upper, 
with amounts tapering off as one goes further south.

&&

.SHORT TERM...(Sunday night through Tuesday)
Issued at 308 PM EST Sat Feb 25 2017

...Turning more quiet to start next week...

High impact weather potential: Minimal. Sunday's fast-moving clipper 
exists Sunday evening. Another storm system is possible late Tuesday 
through the midweek timeframe; however, details regarding 
strength/timing/p-type remain uncertain.

Pattern Forecast: Sunday's upper-level shortwave and associated weak 
surface low pressure are progged to be exiting the region Sunday 
evening with weak upper-level ridging expected to prevail Monday 
into the first half of Tuesday. Bubble of high pressure rooted at 
the surface, combined with WAA/weak thermal ridging to start the 
work week should help to provide partial sunshine and slightly above 
normal temperatures. The next weather-maker locally begins to ramp 
up late Tuesday through Wednesday as the jet stream buckles, energy 
digs into the four corners region, and cyclogenesis gets underway 
across the southern plains/Mississippi Valley.

Primary Forecast Concerns: Sunday's fast-moving clipper system 
continues to race eastward Sunday evening. Expecting light snow 
showers to linger through the mid-late evening, especially across 
the northern half of the CWA (steadiest along and north of the 
bridge). Perhaps up to another inch of accumulation in sections of 
eastern Chippewa/Mackinac counties before snow diminishes 
completely. By Monday morning, surface ridging/high pressure is 
expected to be evident across the Great Lakes with thermal ridging 
quick to follow as winds back southwesterly by early afternoon. 
Anticipating dry conditions on Monday with peeks of sunshine and 
temperatures climbing slightly above normal...ranging from low 30s 
north to the low 40s near Saginaw Bay.

Attention quickly transitions to the latter half of Tuesday as low 
pressure ramps up across the southern plains/mid-Mississippi Valley. 
While there is fairly high confidence in a sizable storm system 
moving through the middle of the country during the Tuesday-
Wednesday timeframe, guidance variations in terms of strength, 
timing, and p-type leads to fairly low confidence in the details at 
this juncture. Possible solutions with the first wave/warm front on 
Tuesday vary from a north-south wintry mix to rain gradient, to all 
rain and well-above normal temperatures across much of the area. 
Recent trends continue to suggest a secondary wave and much more 
impressive area of low pressure moving through the southern Great 
Lakes, which has the potential to bring heavy, wet snow to portions 
of northern Michigan. Worth monitoring the Tuesday-Wednesday 
timeframe in future outlooks.

&&

.LONG TERM...(Tuesday night through Saturday)
Issued at 308 PM EST Sat Feb 25 2017

Another system moving out of the Plains is set to impact the Great 
Lakes near mid-week next week. There is still a good deal of 
uncertainty with the track, and as has been the case often this 
winter that will have a large impact on p-type and accumulation 
issues for us. Tuesday rains will mix with and change to snow 
overnight into Wednesday. Many areas will see a switch back to rain 
during the day Wednesday, but just how far north that will occur is 
going to be dependent on the track of the aforementioned low. Colder 
air moves back in by Thursday, with things switching over to lake 
effect going into the weekend.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1221 PM EST Sat Feb 25 2017

MVFR/IFR producing lake effect snow showers within gusty 
northwest wind regime will continue to impact the taf locations 
through this afternoon. Conditions expected to steadily improve 
tonight as dry air filters overhead. Fast moving wave may bring 
additional low clouds and snow showers Sunday, with the greatest 
concern at KPLN where lake contributions may help the snow 
producing cause. Winds slacken tonight only to become gusty out of
the southwest on Sunday.

&&

.MARINE...
Issued at 308 PM EST Sat Feb 25 2017

Gusty northwest winds continue, with some briefly reaching 
gale force on northern Lake Huron. This will continue into this 
evening, with winds temporarily decreasing overnight. Next system 
rapidly approaches for Sunday, with gusty southwest winds developing 
out in front of it. More headlines will likely be needed on Sunday, 
with even a few gale gusts possible in the Manitou Passage where 
coastal convergence will be maximized. Light winds return Sunday 
night on into the start of next work week.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY until 7 PM EST this evening for MIZ008-
     019>022-025>027-031-032.
LH...SMALL CRAFT ADVISORY until 5 AM EST Sunday for LHZ345-346-349.
     GALE WARNING until midnight EST tonight for LHZ347-348.
LM...SMALL CRAFT ADVISORY until 5 AM EST Sunday for LMZ323-341-342-
     344>346.
LS...NONE.
&&

$$

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