Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 152352
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
652 PM CDT Fri Mar 15 2024

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Lake effect snow showers return this weekend over the snowbelt
  region of northern Wisconsin. Snow accumulations of a couple
  inches are expected over northern Vilas County by Monday, with
  little to no accumulations elsewhere.

- Northwest winds may gust to 25 to 35 mph on Saturday, strongest
  from central to east-central Wisconsin.

- One more day of above normal temperatures Saturday, then
  temperatures fall below normal Sunday into Monday.

&&

.DISCUSSION...
Issued at 404 PM CDT Fri Mar 15 2024

Short Term...Tonight and Saturday

Above normal temperatures will persist through Saturday but changes
are in the offing. This afternoon, flatter flow aloft is present
this afternoon over the western Great Lakes downstream of sharp
trough digging across central Canada. At the surface, ridging
extends in from the central Plains. Dry air aloft has led to yet
another day with low RHs. Thankfully, at current, winds are light.

Trough upstream will dig southeast, crossing north of Lake Superior
late tonight. Limited moisture but could be a few rain/snow showers
near the Upper Michigan border as this moves by. Lead sfc cold front
will dive across Wisconsin, exiting across Lake Michigan on Saturday
morning. Southwest winds tonight will increase ahead of the cold
front then shift west-northwest late tonight through Saturday. Wind
gusts later tonight will be up to 20 mph but gusts on Saturday still
look to reach 25-35 mph, strongest from central to east-central WI.
Skies will turn mostly cloudy late tonight, but may see some partial
clearing over east-central Wisconsin just behind the cold front.
Eventually though, low-level moisture builds as the day progresses
and soundings and higher-res guidance points to scattered mainly
snow showers (20-30 percent) over north-central WI with maybe
some spits of sprinkles farther south even toward central and
northeast WI. Temperatures will be tricky even though we are
behind the initial cold front. Could see far northeast to east
central areas reaching past 50F with expected mixing and some
downslope. Temps over north- central WI will be held down in the
mid to upper 30s with continual cold air advection and more of an
upslope flow.

Long Term...Saturday Night Through Friday

Main focus from this forecast period revolves around lake-effect
snow showers across the northern WI snowbelt from Saturday night
through early Monday.

Precipitation...The Great Lakes region will be under the influence
of a cyclonic flow from Saturday night through Monday. At the
surface, a low pressure system will track from central Ontario to
southeastern Quebec. CAA, low-level north/northwest winds, and delta
Ts of 14-18 will prevail through this time and allow the lake-effect
snow machine to turn on across northern WI. Flurries are possible at
times across the rest of the forecast area during this time as well.
Vilas County will see the highest snowfall amounts of at least 1 to
3 inches by Monday, with little to no accumulations anticipated
elsewhere. Locally higher amounts in the far northwest corner of
Vilas County are possible as NBM probabilities of 5 inches or more
of snow are around 10-30%. The upper-level pattern will transition
to a northwest flow on Monday, and continue through midweek. Models
indicate a few impulses could bring light precip chances at times,
but there`s too much uncertainty to nail down specifics.

Temperatures...The prevailing CAA will cause temperatures to take a
dip below normal for Sunday and Monday, with highs ranging from the
upper 20s to upper 30s. Temperatures will bounce back to around or
slightly above normal for the rest of next week with highs mainly in
the upper 30s and 40s.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 636 PM CDT Fri Mar 15 2024

SCT-BKN high-based stratocumulus clouds were impacting the region
early this evening, with a more solid deck of mid-level clouds
approaching from NW WI. These clouds will overspread the region
as a cold front approaches tonight.

Westerly surface winds less than 10 kts will back to the southwest
tonight and increase to 10 to 15 kts with gusts to around 20 kts.
Increasing southwest winds aloft (35 to 40 knots at 2k ft AGL)
will cause LLWS beginning in far NC WI late this evening, and
lasting through early Saturday morning in EC WI. The LLWS will end
as the cold front moves through.

The cold front will pass through the western TAF sites late
tonight, and the eastern TAF sites early to mid-morning Saturday.
A few light rain and snow showers are expected close to the Upper
Michigan border as the front passes late tonight. Expect mostly
cloudy skies behind the front on Saturday, with scattered snow
showers or flurries over north central WI at times. VFR conditions
will occur in most places, though MVFR can be expected over NC WI
late tonight through much of Saturday. WNW winds will gust to
25-30 kts at all TAF sites starting mid-morning Saturday.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION.....JLA/Kruk
AVIATION.......Kieckbusch


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