Appleton, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

606
FXUS63 KGRB 301148
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
548 AM CST Thu Jan 30 2025

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Record warmth likely over much of the area today. Many
  locations from central to east central Wisconsin, including the
  Fox Valley, could see temperatures reach 50 degrees.

- Low pressure system to impact Wisconsin Saturday afternoon into
  Sunday morning. There is a 60-90+% chance of 2 inch or more of
  snow north of a Wausau to Marinette line. There is a 40-60%
  chance of 4 inches or more of snow over portions of northern
  Wisconsin.

&&

.DISCUSSION...
Issued at 352 AM CST Thu Jan 30 2025

Short Term...Today...Tonight...and Friday

Quiet through Friday with main focus on record warmth today. Weak
moisture starved clipper tracks from the northern plains across
the northern Great Lakes this afternoon, then across southern
Ontario and Quebec tonight. Flurries have attempted to get going
near the Michigan border due to mid-level warm air advection and
frontogenesis ahead of the weak low, but it has been a struggle.
Any flurries will end by daybreak over far northeast Wisconsin.
After basking in the warmth today, once the low passes to the
east, a cold front will drop south across the area tonight. Plan
on a cooler day Friday behind the front with gusty northeast
winds, especially closer to the bay and Lake Michigan. A few lake
effect flurries could drift across far northern Wisconsin by
afternoon. Bigger system through Friday develops over the central
Plains today, but main area of precipitation, mostly in form of
rain, looks to stay south of our area on Friday.

Record Warmth...South-southwesterly low-level flow develops early
this morning and lasts through this afternoon. This allows warmth
over the plains to spread into western Great Lakes. Mixing to
925mb temps supports highs around 50 or into lower 50s mainly
south of highway 29 where no snow is on the ground, with mid to
upper 40s into far northeast Wisconsin. Still some snow on the
ground northwest of Wausau to Iron Mountain, so given lack of real
deep mixing, tempered highs a bit there, with readings mainly
reaching around 40 into the lower 40s. Many daily record highs
for January 30, are in jeopardy of being broken. These warm
temperatures will also raise concerns for the stability of
ice/ice thickness on inland lakes, rivers, and ponds. Southwest
winds could gust to 25-30 mph for a brief time late morning into
the afternoon, mainly from the Fox Valley to the lakeshore. Some
brush fires have developed this week during breezy days where
there is no snow cover, so will need to monitor for this potential.

Jan 30 Record High..Year (Forecast High)
Appleton..........45..1989 (53)
Green Bay.........43..1989 (53)
Manitowoc.........47..1988 (50)
Marshfield........47..1919 (50)
Oshkosh...........45..1989 (52)
Rhinelander.......44..1999 (42)
Stevens Point.....43..2016 (51)
Sturgeon Bay......43..1988 (46)
Wausau............43..1999 (48)
Wisconsin Rapids..46..1974 (51).

Long Term...Friday Night Through Wednesday

Accumulating snow remains on on track for late Saturday through
Saturday night, especially north, as stronger jet stream refocuses
over the northern tier of the country, allowing a shortwave
trough/modest strength low pressure system to track across area
from the northern plains. This system may produce enough snow to
justify eventual headline for some of our area, but that is not
quite certain yet. Snow may end as wintry mix late Saturday night
into Sunday morning, before another well above normal afternoon
occurs on Sunday. Cold front follows though, with temperatures
trending back below normal for much of next week. Another shot of
light snow is also possible by the middle of the week.

Accumulating snow late Saturday through Saturday night...Moderate
snow accumulations expected due to warm air advection initially
then as the primary shortwave trough/fgen crosses the region. NBM
and LREF probabilities along with means of ensemble plumes point
to areas north of Wausau to Marinette to see the most snow from
this system. NBM probabilities for over 2 inches of snow over 90
percent in some areas of northern WI, with values for over 4
inches 40-60 percent in the same areas. Sharper southern edge
though as chances of even over 1 inch drop off to less than 50
percent south of highway 29, including not even reaching 30
percent at Oshkosh. A lot of numbers, but main point is if this
system overachieves, it will more likely be in the north versus
the south.

Also, looking at the forecast soundings, there is concern of losing
moisture in the DGZ before 12z Sunday, even over the north, which
would lower SLRs, possibly cut down on snow amounts and even
introduce potential for wintry mix, including freezing rain or
freezing drizzle, as the moist layer is still below freezing when
drying aloft occurs. Also of concern is lack of consistency from
model to model run and even in the same model from run-to-run as
to where heaviest qpf/snow develops Saturday night. Still some
items to sort out with the system, but the general messaging will
remain the same, with at least a few inches of snow expected over
our northern areas and possible hazardous travel.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 542 AM CST Thu Jan 30 2025

Sfc low tracking north places area within increasing southwest
low-level flow into this evening. Brief low-level wind shear this
morning at AUW/CWA/RHI as stronger winds arrive aloft. Eventually
GRB/ATW and MTW could see gusts 20-25 kts this afternoon. Mid
clouds over the north exit this morning, leaving just scattered
high clouds for the day into this evening.

Cold front drops south across Wisconsin late tonight. Winds will
shift to the northeast behind the front, and there is a potential
for scattered-broken MVFR clouds to develop late over far northern
and far northeast Wisconsin.

&&

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

&&

$$

DISCUSSION.....JLA
AVIATION.......JLA