Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

000
FXUS63 KGRB 161122
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
622 AM CDT Sat Mar 16 2024

Updated aviation portion for 12Z 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.

- West to northwest winds may gust to 25 to 35 mph today,
  strongest from central to east-central Wisconsin.

- Northwest to north-northwest winds will continue to gust to 20
  to 30 mph tonight through Sunday evening before dissipating
  Sunday night.

- Temperatures remain above normal today, then fall below normal
  Sunday into Monday.

&&

.DISCUSSION...
Issued at 341 AM CDT Sat Mar 16 2024

Short Term...Today...Tonight...and Sunday

A cold front is currently sweeping through northeast Wisconsin
this morning. However, despite some echo returns on doppler radar,
nothing is currently reaching the ground across the area. There is
currently abundant low level dry air in place, as evidenced by the
00Z raob sounding and still high ceilings indicated by the METAR
observations. In addition, upstream observations indicate very
few sites with precipitation hitting the ground. Therefore, the
cold front will mainly be marked with a shift in wind direction
from southwest to west and eventually west-northwest throughout
the day along with cooler temperatures, especially across north-
central Wisconsin, and gusty surface winds of 25 to 35 mph. The
front could bring some sprinkles or flurries across far north-
central and northern Door County, with minimal impacts. Highs
today are expected to mainly range from the lower 40s across the
north, to the lower 50s across east- central and northeast
Wisconsin.

Although moisture will initially be at a premium today, model
soundings indicate moisture will increase throughout the day as a
vigorous mid level shortwave tracks through the western Great
Lakes region tonight as winds turn northwesterly. This will allow
some moisture to advect in from Lake Superior, which will further
boost the chance for precipitation across north-central Wisconsin
tonight. Delta-T values during this period will increase from
around 13 this evening, to the middle teens by late tonight. This
should bring periods of light snow showers to north-central
Wisconsin tonight (30-60 percent chance) with 1 to 2 inches of
snow possible across far northern Vilas County and a dusting
possible elsewhere further away from the main lake effect bands.
Colder air advecting in on northwest winds will cause lows to fall
into the upper teens across the north, with upper 20s across
east-central Wisconsin and the lakeshore. Although surface winds
will die off a bit tonight, they will still gust to 20 to 30 mph
at times.

Moisture will continue to increase across the region on Sunday as
a mid level shortwave tracks through the western Great Lakes
region. Winds will turn north-northwest on Sunday, which will
continue the chance for lake effect across north-central
Wisconsin with Delta-T values in the upper teens. The increased
moisture and mid level shortwave will bring the chance (10-20
percent) for some light snow/flurries/sprinkles across central,
northeast, and east- central Wisconsin mainly during the afternoon
hours. Farther north, the deeper moisture from Lake Superior will
keep chances higher (30-50 percent) across north- central
Wisconsin with some pre-conditioning from Lake Superior and Lake
Michigan bringing higher chances (20-30 percent) to northern Door
County than areas further inland. Additional snowfall amounts will
remain light on Sunday, with up to an inch possible across far
northern Vilas County and little to no accumulation elsewhere
given the lack of a steady stream of moisture. Highs on Sunday are
only expected to rise into the middle to upper 20s across north-
central, with middle 30s across east-central and northeast
Wisconsin. Surface winds will continue to gust to 20 to 30 mph on
Sunday.

Long Term...Sunday Night Through Friday

Main focus for the extended period is lingering lake effect snow
across north-central WI through mid-day Monday.

Precipitation...Lake effect snow is expected to continue through
Monday morning across north-central WI, mainly Vilas County, as
winds remain out of the northwest. As winds back and become more
westerly Monday afternoon the snow will come to an end. Total snow
accumulations are expected to be highest in northern Vilas Co.
where the probability for greater than 2" is 60-80% and the
probability for greater than 5" is 10-30%. Probabilities drop off
quickly further south. As the cyclonic flow that brought the lake
effect snow shifts off to the east a mean northwest upper-level
flow regime will move over the region. Guidance has been picking
up on signs for a weak impulse moving across northern WI Tuesday
which could bring another chance for some light snow across the
north, but there is still too much uncertainty to pin down the
details. Surface high pressure moving across central Canada is
expected to keep the middle of next week mostly dry. Looking
toward the end of next week both the GFS and ECMWF are showing
signs for the next chance of widespread precipitation, however,
there are notable differences in the timing and intensities with
this system between models so left NBM PoPs Thursday and Friday.

Temperatures...The prevailing northwest winds through much the
extended period will bring seasonal to slightly below normal
temperatures. Highs each day are expected to range from the low
30s to low 40s, except Tuesday which may see slightly warmer
afternoon temperatures. Overnight lows are expected to range from
the mid teens to mid 20s each night.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 621 AM CDT Sat Mar 16 2024

A cold front continues to make its way through northeast Wisconsin
this morning. The front is basically dry, marked only be a shift
in wind direction to the west with gusts of 20 to 25 kts, as low
level dry air prevents any precipitation from hitting the ground.
Mostly cloudy skies are expected behind the front today, with
scattered snow showers or flurries across north-central Wisconsin,
becoming more numerous during the evening as lake effect starts
across that area. VFR conditions are expected across most
locations, with MVFR conditions across north-central Wisconsin at
times with the snow showers this afternoon and evening.

Surface winds will increase this morning behind the cold front and
the boundary layer mixes and turn westerly. Some LLWS is expected
across central and east-central Wisconsin until this occurs for a
few hours. Surface winds will gust to 25 to 30 knots at times
today, then turn northwesterly and gust to around 20 knots
tonight.

&&

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

&&

$$

DISCUSSION.....Kurimski/GK
AVIATION.......Kurimski


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.