389
FXUS63 KGRB 200401
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1101 PM CDT Sat Apr 19 2025

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- Widespread precipitation arrives late Sunday into Monday with
  rainfall totals of 0.75-1.00" for most locations. Some river
  rises are expected during the upcoming week, but widespread
  flooding not expected.

- The rain will mix with snow across north central Wisconsin late
  Sunday night into Monday, with a minor accumulation possible on
  grassy surfaces.

- Cooler temps arrive to start the new week, but a warm up is on
  tap by Wednesday, with periodic rain chances through the week.

&&

.DISCUSSION...
Issued at 338 PM CDT Sat Apr 19 2025

High pressure will move through the area tonight into
early Sunday, with clear to partly cloudy skies expected.
Patchy fog may develop in northern WI late tonight, especially
in east wind flow upslope areas and the typical cold spots.
Low temperatures will be in the 20s north and lower to middle
30s south.

Dry conditions persist into early Sunday afternoon, but low
pressure approaching from the Central Plains will spread light
rain into areas south of Hwy 29 late in the day. Before the
rain arrives, temperatures will get into the lower to middle 50s.

Widespread rain overspreads the forecast area Sunday night as
strong WAA/isentropic lift develops in association with a 35-50
knot low-level jet and passage of a short-wave trough. Low-level
temperatures and thicknesses support potential for at least a
rain/snow mix over far north central WI late. Widespread
precipitation continues through Monday morning as a deep upper
low/trough moves through the region. Potential for snow continues
over the NW part of the CWA. Probabilistic forecasts show a 20-50
percent chance of 1+ inches over far NC WI, and 10-30 percent
chance of 2+ inches. Gusty east winds will develop as the low
approaches Sunday night, followed by gusty northwest winds as the
low lifts NE of the region Monday afternoon. This will bring
gusts to 25 to 35 mph at times, along with hazardous conditions
for small craft on Lake Michigan.

A brief period of dry weather is expected Monday night, but
a short-wave trough and low pressure system approaching from
the Northern Plains will bring a chance of showers Tuesday into
Tuesday night.

Dry weather is anticipated Wednesday, but another low pressure
system approaching from the plains will lift northeast through
the western Great Lakes and bring showers late Wednesday night
into Thursday night. Drier conditions should return Friday into
Saturday as high pressure builds into the region.

Temperatures will start out cool on Monday, followed by a
moderating trend into midweek.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1100 PM CDT Sat Apr 19 2025

VFR conditions prevail tonight into Sunday afternoon, then conditions
will deteriorate to IFR by Sunday evening as a low pressure system
and widespread rain moves in from the south. Rain and fog will
then spread across the entire area Sunday evening into the overnight
hours Sunday night. As winds turn southeast later tonight, there
is a signal that scattered to perhaps broken IFR to low MVFR
clouds and patchy light fog may develop from central to north-
central WI. Confidence in prevailing stratus deck remains low, so
will include scattered cloud groups at CWA/AUW/RHI, but only put
TEMPO group for lower vsby in at RHI.

Light east winds tonight will increase on Sunday to 15-20 kts.
Gusts to 20-25 kts will occur on Sunday night.

&&

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

&&

$$

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