687
FXUS63 KMQT 121136
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
636 AM EST Wed Feb 12 2025

.KEY MESSAGES...

- Mid-week system brings a round of light snow this afternoon
  into Thursday. Generally 1 to 2 inches is expected, highest
  over the east half of Upper Michigan.

- Moderate lake effect snow showers will be possible Thursday
  across eastern Upper Michigan.

- Widespread light to moderate snow expected Friday night into Saturday
  may result in some hazardous road conditions.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 319 AM EST Wed Feb 12 2025

It`s a still and cold morning with current sfc obs showing little to
no winds and temps mainly below 0F across the UP. Looking at the
current RAP analysis, this is thanks to the high pressure analyzed
across MN, the Upper Great Lakes and into Quebec. Also, dry low/mid
levels and the lack of insulating low cloud cover has allowed
radiative cooling to drop temps into the -teens with some typical
cold spots hitting -20s over the west. Some single digits above 0F
temps remain in a few spots near Lake Superior and in the Keweenaw,
but also in the east where satellite imagery shows the lake effect
clouds coming off Lake MI. Current temps are below available
guidance so confidence in the hourly temp forecast is not high, but
increasing cloud cover and some WAA will prevent further major drops
in temp the rest of the morning. With widespread temps likely to
remain above -25F west/-20F east and no wind, opted to not issue any
Cold Weather Advisories. Otherwise, lingering west-southwest wind
lake effect snow showers primarily only over Lake Superior may drop
up to 1" of fluffy dry snow in the Keweenaw through around sunrise.

Attention turns to the shortwave currently lifting northeast from
CO. This shortwave lifts to Lower MI through tonight, bringing a sfc
low from the Lower Mississippi Valley to southern Ontario. WAA and
PVA out ahead of the sfc low supports the precip shield expanding
northeast over the UP this afternoon, continuing into tonight. Any
snow showers earlier would occur near the Garden Peninsula thanks to
cold 850mb temps near -17C over Lake MI (~25% chance). While the
best dynamic support and moisture remains to our south, 1-2" of snow
is expected into Thursday, highest totals are expected over the
east. Localized areas up to 3-4" are possible in Delta and Southern
Schoolcraft counties with any preluding LES and further lake
enhancement. Otherwise, temps today peak in the teens save for a few
spots reaching 20F along Lake MI.

The pattern transitions back over to LES tonight on the backside of
the sfc low as a cold front moves in from the west. 850mb temps
return to -15C to -20C (colder west) behind the cold front. With low
level convergence along the cold front and periods of low level
moisture, 1-2" of LES snow is possible by Thursday morning over the
northwest wind snow belts. Lows settle into the single digits, with
some falling below 0 in the interior west by Thursday morning.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 226 AM EST Wed Feb 12 2025

Long term period begins Thursday at 12z when broad mid-upper level
low and negative height anomaly over central Canada extends
troughing south into middle-CONUS. Main shortwave within this flow
will be extended across the Arrowhead southward into Wisconsin/Iowa
while a surface low is positioned near Lake Erie. Surface trough
extending from the low across Lake Superior will help aid snow
shower production into Upper Michigan through the day while the
shortwave presses east and lifts the surface low northeast into
Quebec. High pressure ridging will press in from the west through
the day Thursday and linger Friday. The ridging should help lift
showers from the northwest wind snowbelts to the westerly snow belts
in the west half through the day Thursday while the northwest wind
snowbelts remain snowy in the east. By nightfall, ridging should
continue lifting showers northward into the lake. Cold air advection
in the morning/early afternoon will help 850mb temps fall to around -
22C, which will help lower the DGZ. Ridging and the cold air in the
west should work against significant snow accumulations. However, in
the east, enhanced convergence may support moderate lake effect snow
bands and/or meso-lows over the lake, which should press into
Alger/Luce counties. Daytime highs on Thursday look to be in the
single digits far west to low 20s far east. Overnight lows below
zero are expected for most of the forecast area Thursday night, with
the greatest potential of dropping below 10 below in the interior
west (NBM suggests 40-60% chance).

Upstream on Friday, troughing over western CONUS will eject out a
shortwave into the Central Plains. Overrunning precip associated
with a warm front looks to spread across Minnesota/Wisconsin by
afternoon. This snow will spread into Upper Michigan beginning in
the evening then persist through early afternoon Saturday. Current
EPS and GEPS probabilistic guidance suggests highest snowfall amounts
are expected across the south-central where the greatest potential
of exceeding 3 inches of snow exists (30-50% chance). This may be
underdone given these system`s defaulting to 10:1 snow ratios. NBM
suggests notably higher probabilities (e.g. ~65 chance of
exceeding 6 inches in Menominee). Synoptic snow should end west to
east through the day, followed by lake effect snow showers off of
Lake Superior into next week. Another shot of cold air will build in
behind the snow Saturday, then linger into early Tuesday. Coldest
air will be here Sunday night through Tuesday morning when
widespread below zero temps are expected. Negative teens will be
possible interior west. Monday highs may struggle to climb into the
teens.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 636 AM EST Wed Feb 12 2025

VFR conditions will prevail into this afternoon at SAW and into this
evening at IWD and CMX. A low pressure system passing well to the S
will brush portions of the UP with -sn this afternoon and evening.
Behind this system, a transition over to LES is expected into
Thursday as a colder airmass returns from the NW. Opted to keep IWD
dry until late tonight, adding a PROB30 for -shsn. CMX will be
similar to IWD, but -shsn start much earlier this evening with IFR
vis reductions possible. System snow arrives at SAW around 20Z with
conditions deteriorating into this evening. Added a PROB30 for -shsn
into Thursday at SAW. Otherwise, general deterioration down to MVFR
conditions is anticipated into this evening, continuing into
Thursday. Light and variable winds also continue much of the period,
becoming NW ~10kts by Thursday morning.

&&

.MARINE...
Issued at 226 AM EST Wed Feb 12 2025

Light winds, below 20 knots will continue into this evening.
Overnight, tightening pressure gradient across the northern and
eastern portions of Lake Superior will result in northwest winds
increasing to near 30 knots. Isolated gale force gusts will be
possible Thursday. Winds look to relax below 20 knots by the evening
hours and should remain light on Friday. Another system moving
through the region early this weekend may support southerlies
increasing to 25-30kts across the east half Friday night. Behind the
system, northerly winds look to increase to near 25 knots Friday
night into early Sunday. Cold air over the lake will also support
periods of heavy freezing spray, particularly Thursday across eastern
Lake Superior.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Heavy Freezing Spray Warning from 7 AM to 4 PM EST Thursday
     for LSZ244-245-248-264-265.

  Heavy Freezing Spray Warning from 7 AM Thursday to 1 AM EST
     Friday for LSZ249-250-266.

  Heavy Freezing Spray Warning from 1 PM Thursday to 7 AM EST
     Friday for LSZ251-267.

Lake Michigan...
None.

&&

$$

SHORT TERM...Jablonski
LONG TERM...JTP
AVIATION...Jablonski
MARINE...JTP