Appleton, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

908
FXUS63 KGRB 230758
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
158 AM CST Sat Nov 23 2024

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- The chances for light rain and snow from Sunday night through
  Monday night have increased. There is a 40-50% chance of getting
  at least 1 inch of snow in north-central WI, and a 30% chance
  to get at least 2 inches of snow.

- Light lake effect snow at times over far north-central Wisconsin
  mid to late next week. Only minor accumulations are expected.

- A cooling trend takes hold for the coming week. Highs in the 30s
  and 40s into Monday will cool into the 20s to 30s by the middle
  of the week, and into the 20s across the entire area by next
  weekend.

&&

.DISCUSSION...
Issued at 158 AM CST Sat Nov 23 2024

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

The latest RAP analysis and satellite/radar imagery show Wisconsin
positioned between high pressure over the northern Plains to mid-
Mississippi Valley to low pressure off the east coast. Northwest
flow across eastern Wisconsin is helping to maintain MVFR stratus
over eastern WI early this morning. Additional clouds above 8000
ft are streaming in from the west ahead of the next storm system.
Focus of this forecast generally revolves around cloud trends and
light precip chances on Sunday afternoon.

Cloud Trends: Cyclonic flow will abate today as a weak surface
ridge axis moves into western Wisconsin during the afternoon.
Winds will back in response which should bring modestly warmer low
level air into central and east-central WI. However, as winds
back, models are hinting at a narrow fgen band spreading from
west to east across central WI and the southern Fox Valley this
morning that will keep plenty of clouds around. Could see a few
sprinkles and flurries within this fgen band from this morning
through about mid-afternoon. Low level temps also remain colder
across the far north which will make it more difficult for clouds
to erode. So therefore remained more pessimistic about clearing
today.

While partial clearing may occur late this afternoon into the
evening, thicker mid and high clouds will move into the region
tonight and Sunday. In the low levels, isentropic ascent will
increase from late Sunday morning through the afternoon with
saturation taking place between 850-750mb. In the end, think the
day will end up being mostly cloudy to overcast.

Sunday Afternoon Precip Chances: Some differences in the models
with how deep low level saturation grows on Sunday afternoon. The
NAM is the most aggressive, and produces saturation up to 750mb
which would be favorable for drizzle or light showers. Other
guidance do not produce nearly as deep saturation. Will side with
the majority and keep the area dry.

Temperatures: Highs in the middle 30s to lower 40s today will warm
a couple degrees into the upper 30s to middle 40s on Sunday.
Raised low temps tonight as cloud cover should slow the nocturnal
fall of temps.

Long Term...Sunday Night Through Friday

Low pressure system will bring widespread chances for rain/snow
Sunday night through Monday night. Turning colder for the rest of
the week with some light snow possible either from a clipper or
lake effect, especially north-central WI.

Precip/snow...Shortwave trough exiting the intermountain west will
cross the western Great Lakes Monday and Monday night. At this
point, deterministic models point to sharpening of the sfc low
with this wave over central and lower Great Lakes later Monday.
Ensembles do show some potential of stronger low farther west which
would result in more precip over WI, including accumulating snow
at least over north-central WI. Overall did not stray much from
going forecast, with a few inches of snow over far north-central
WI Monday through Monday night. East-central WI is still expected
to get primarily rain, but some snow with minimal accums could
mix in as far east as the Fox Valley and lakeshore later Monday
night.

Once the system shifts by, rest of the pops/snow chances for the
week will be due to NW flow lake effect. Not greatest setup for
much snow over the north due to wind direction, but light accums
will occur at times across Vilas, Forest and Florence counties.
ECMWF hints at clipper wave in northwest flow pattern aloft
late this week, but operational GFS or Canadian, as well as
ensembles from those models and even the the ECMWF, don`t really
have this idea. Something to watch as it would result in chances
for light snow or flurries most areas, but will just keep with NW
flow lake effect pop idea at this time.

Temperatures...Temps will be steady Sunday night into Monday as
the low pressure system tracks across. Cooler air spills in for
Tuesday and Wednesday with highs upper 20s to around 30 north,
to mainly the mid 30s from central WI to the lakeshore. Similar
readings for Thanksgiving, then even colder air arrives with
highs in the 20s for the entire area by next weekend.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1128 PM CST Fri Nov 22 2024

A low cloud deck will remain in place across the region through
the overnight hours, keeping MVFR cigs in place for most sites.
Ceilings could dip to IFR for most of the TAF sites at times as
clouds lower a bit, mainly across central and north-central
Wisconsin. Some patchy fog is possible north of Rhinelander, but
not currently expected to make it into the RHI vicinity. Finally,
some improvement in sky cover will arrive from the southwest
Saturday morning, gradually lifting cigs to MVFR and possibly low
VFR Saturday afternoon or evening. Across the north some partial
clearing is possible, while model soundings show improvement to
VFR will likely be late Saturday afternoon or Saturday evening
elsewhere.

&&

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

&&

$$

DISCUSSION.....MPC/JLA
AVIATION.......Kurimski