718
FXUS63 KGRB 191102
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
602 AM CDT Sun Apr 19 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

-Minor to moderate flooding continues on many rivers, with major
 flooding expected on the Wolf River through Tuesday. Water levels
 have crested in most areas, and due to an extended period of dry
 weather, a gradually drop is anticipated through the week.

-Showers and thunderstorms are likely Thursday night into Friday.
 With a low end (5-15%) chance for strong to severe storms,
 mainly across central and north-central WI.

-Temperatures will be be below normal through Monday, with much
 above normal temperatures in the 60s and 70s expected Tuesday
 through Friday.

&&

.DISCUSSION...
Issued at 151 AM CDT Sun Apr 19 2026

Continued northwesterly flow today will keep temperatures well below
normal. Highs this afternoon are only expected to reach the middle
30s across northern WI to the upper 40s in the Fox Valley. A subtle
short-wave, currently over western MN, passing through the broader
upper trough will bring a slight chance (10-20%) for scattered
flurries across central and east-central WI this morning. A dusting
of snow accumulations on grassy surfaces is possible, however, don`t
expect any travel impacts. Forecast soundings for today also show
the PBL becoming deeply mixed, up to 8kft, which will lead to a
substantial decrease in dew points, especially across northern WI.

The first half of next week will be dominated by upper-ridgeing
leading to mostly dry and near to above normal temperatures. Medium
range ensembles do show a cold front sweeping across the region
Monday which could kick of scattered sprinkles across northern WI,
however, with such a dry airmass in place think this will be a dry
frontal passage for most locations.

Main focus of the extended forecast is late Thursday into Friday and
the next chance for widespread showers and thunderstorms move into
the western Great Lakes. Mean upper-level flow fields show a broad
trough developing over the Northern Plains which drags a cold front
through the forecast area Thursday night into Friday. Ahead of the
front substantial northward moisture transport will increase PWATS to
1.2-1.3", which is over the 99th percentile of climo. The increase
in moisture also leads to moderate destabilization with mean MUCAPE
values increasing to 800-900 J/kg. This would create an environment
favorable for stronger thunderstorms and locally heavy rainfall. If
you have travel or outdoor plans Thursday evening or Friday make
sure to monitor the forecast as details become more clear.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 602 AM CDT Sun Apr 19 2026

Compact short-wave currently over western WI will swing across
central and east-central WI this morning producing a short period of
snow showers south of a CWA to GRB line. As snow showers pass over
any terminal cigs and vsbys will become MVFR for a short time
before turning to VFR. Snow showers should exit the region by 15Z
with VFR conditions through through the remainder of the TAF
period. A cu field will likely develop late this morning based around
4.5kft and rise to around 6kft by this afternoon.

While not as strong as yesterday northwest winds will be breezy
again today with peak gusts of 20-25 kts this afternoon.

&&

.HYDROLOGY...
Issued at 151 AM CDT Sun Apr 19 2026

Minor to moderate flooding continues on many rivers, with major
flooding expected to persist on the Wolf River through Tuesday.
Most of the river levels have crested, and with a prolonged
stretch of dry weather anticipated through Thursday, water levels
should gradually subside through the week.

Those living near rivers should continue to monitor the latest
Flood Warnings and statements from the National Weather Service in
Green Bay.

&&

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

&&

$$

DISCUSSION.....GK
AVIATION.......GK
HYDROLOGY......GK

NWS GRB Office Area Forecast Discussion