273 
FXUS63 KAPX 050529
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1229 AM EST Fri Dec 5 2025

.KEY MESSAGES...

- Light snow tonight with some lake enhancement in southwest flow 
off Lake Michigan...round 1.

- More widespread snow Friday night with (maybe) some lake 
enhancement off Lake Michigan...round 2.

- Windy and colder Saturday with lake effect snow showers returning.

- Another round of synoptic snowfall in the Sunday time frame.

- Alberta clipper around Tuesday? Maybe...

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 358 PM EST Thu Dec 4 2025

Pattern Synopsis/Forecast: Full latitude long wave trough 
encompasses North America this afternoon...some impressive 500mb 
height/temperature anomalies within the core of the trough over 
Ontario/Quebec (-2 to -3 sigma standardized height anomalies/-48C 
with the thermal trough).  Large scale pattern is amplified all the 
way across the Pacific Basin...with -EPO ridging over the eastern 
Pacific.  But things are shifting...trough axis is east of the upper 
Lakes this afternoon as a strong PV anomaly (dynamic tropopause 
below 600mb) rotates across southern Ontario/Quebec with height 
rises just upstream.  Mid level warm advection already underway 
across the upper Midwest and spreading into Wisconsin/ Michigan... 
ahead of another short wave trough digging southeast out of Manitoba 
(better defined at 700mb). 

Surface analysis shows a 1035mb high centered over Iowa...in the wake 
of yesterday's cold front passage.  Sharp mesoscale troughing runs 
southeast/northwest across Lake Huron/Lake Superior due to lake 
heating.  Surface cold air was "horseshoeing" around the upper 
Lakes...but an impressive textbook example of cold air draining off 
the higher terrain east of Lake Superior and into eastern Upper 
earlier this morning.  Winds at CYAM were gusting to 43kts from the 
northwest before the wind flipped to northeast and the temperature 
dropped 9F.  So even against that background flow the density current 
was able to overcome that and dropped all the way into northern Lake 
Huron.

Surface high over Iowa slides south of Michigan this evening... 
swinging boundary layer winds to the southwest while upstream short 
wave trough crosses Lake Superior during the early morning hours. 
This will be followed by another short wave trough tracking farther 
south than the previous one...arriving Friday night and pushing a 
cold front across Michigan that will bring a renewed shot of cold 
air for the weekend.

Primary Forecast Concerns:  

Light snow tonight with some lake enhancement in southwest flow off 
Lake Michigan...round 1: Backing low level winds already underway 
this afternoon...which will push existing multiband convection east 
and northeast and should get some southwest flow bands going on 
northern Lake Michigan.  These look to be relatively shallow to 
start but the cloud layer is within the DGZ thermal range with an 
inversion height around 800mb.  Most of this activity should be 
focused into eastern Upper and the tip of the mitt.  Isentropic 
ascent will spread mid/high level moisture across roughly the 
northern half of the forecast area this evening...but there is a dry 
layer between the higher level clouds and the top of the CBL.  So 
initially there won't be seeder-feeder enhancement...but the column 
is expected to moisten after midnight and some increase in low level 
convergence which may be a signal of a more dominant band getting 
organized.  Anticipating a boost in snow intensity into eastern 
Upper and the Straits region overnight and into Friday morning. 
Eventually looks like a band of snow will propagate southward across 
northern Lower Friday (more on this below).  

So for snow amounts in the enhanced areas do think that parts of the 
eastern Upper plus Emmet county zones are going to be pushing 
advisory criteria snowfall amounts (in the 3-6 inch range roughly 
from midnight to noon).  Far northern Cheboygan county and westerly 
Mackinac county will be close...but snowfall won't be the only issue 
with increasing southwest winds tonight.  Wind gusts of 30 to 40mph 
are likely...so blowing and drifting snow will just add to the 
impact (the drive along US-2 might not be much fun overnight).  Will 
go ahead and hoist a Winter Weather Advisory for the zones mentioned 
above (plus the islands)...will include Cheboygan county to avoid 
getting to cute though it may not get "bad" there until late tonight.

More widespread snow Friday night with (maybe) some lake enhancement 
off Lake Michigan...round 2: Approach of next short wave trough 
Friday afternoon is expected to result in an increase in snowfall 
coverage across northern Michigan.  Good dynamic forcing and steep 
mid level lapse rates could surprise a bit from a synoptic QPF 
standpoint.  But will see about the details of that...mid level 
moisture may strip away overnight ahead of the cold front passage 
(so maybe end with a period of freezing drizzle??).  Not as great a 
lake enhancement signal off Lake Michigan Friday night but it is 
still there and certainly won't hurt the cause; shallow CBL mostly 
at temperatures warmer than -10C may just add a lot more supercooled 
droplets and riming potential to the equation...which would cut down 
on SLR.  But certainly several more inches of snow in the cards for 
eastern Upper/northwest Lower through 1200Z Saturday.

&&

.LONG TERM /TONIGHT THROUGH THURSDAY/...
Issued at 358 PM EST Thu Dec 4 2025

Primary Forecast Concerns:  

Windy and colder Saturday with lake effect snow showers returning: 
Gusty northwest winds will bring colder air into Michigan Saturday 
in the wake of a morning cold frontal passage.  Does not look overly 
impactful at this point (other than the fact that it won't stop 
snowing).  Temperatures probably steady or falling through the 20s 
Saturday.

Another round of synoptic snowfall in the Sunday time frame: Another 
short wave trough in the persistent northwest flow looks to arrive 
Sunday and bring another round of widespread snow...followed by some 
lake effect (again not looking overly impressive).  Another day of 
highs in the 20s (normals this time of year are lower to mid 30s). 

Alberta clipper around Tuesday?  Maybe...: Indications of such an 
event but the details are all over the place.  But PoPs will be 
increasing into the midweek period.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1229 AM EST Fri Dec 5 2025

Worsening conditions late tonight CIU/PLN. Sw flow lake-
enhanced snow will develop and increase in coverage/intensity 
over eastern upper and far northern lower MI. Expect CIU to
become IFR late tonight, and PLN Friday morning, in falling and
blowing snow. Conditions improve to MVFR in the afternoon.

For TVC/APN/MBL, VFR tonight, becoming MVFR cigs/vsbys with 
light snow on Friday. 

S to sw winds become blustery late tonight. Winds diminish a 
bit Friday afternoon.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...Winter Weather Advisory until 11 AM EST this morning for 
     MIZ016-086>088-095-096-098.
     Winter Weather Advisory until 11 AM EST this morning for 
     MIZ017.
MARINE...Gale Warning until 11 AM EST this morning for LHZ345.
     Small Craft Advisory until 5 PM EST this afternoon for 
     LHZ346>348.
     Small Craft Advisory until 5 AM EST Saturday for LHZ349.
     Gale Warning until 11 AM EST this morning for LMZ323-341-342-
     344>346.
     Gale Warning until 11 AM EST this morning for LSZ321.
     Small Craft Advisory until 11 AM EST Saturday for LSZ322.

&&

$$

SHORT TERM...JPB
LONG TERM...JPB
AVIATION...JZ