394
FXUS63 KGRB 141754
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1254 PM CDT Thu May 14 2026

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Showers and isolated thunderstorms expected tonight into
  Friday.

- Dangerous fire weather conditions expected on Friday in Vilas
  County, with a Red Flag Warning in effect.

- Gusty winds, warm temperatures, and low relative humidities will
  result in elevated to near-critical fire weather conditions at
  times through Saturday.

- Periods of heavy rainfall and strong to severe storms are
  possible Sunday night through Monday night.

&&

.DISCUSSION...
Issued at 1254 PM CDT Thu May 14 2026

High pressure will slide east tonight, which will allow strong
return flow to develop tonight in the form of a 35-50 knot low-
level jet, warm air advection, and a moist air mass (PWATs
1.0-1.25 inches) moving into the region. Showers and isolated
thunderstorms will arrive across central and north-central
Wisconsin later this evening, but should weaken as they shift into
northeast and east-central Wisconsin overnight into Friday morning
due to a weakening of the low-level jet. The showers will shift
east of the region by late Friday morning, but partial clearing
and daytime heating should allow a few showers and isolated storms
to redevelop over the northwest half of the forecast area during
the late afternoon and evening. Lows tonight will be in the 40s
and lower 50s, with highs on Friday reaching the middle 70s to
lower 80s away from Lake Michigan. Cooler readings in the upper
50s and lower 60s are expected along the Lake Michigan shoreline
due to onshore winds.

Models show a continued chance of showers and isolated storms
along a weak frontal boundary later Friday night into Saturday,
but would suspect that most of the area will be dry. A pattern
change to southwest flow aloft later in the weekend will bring an
increasingly moist and unstable air mass to the region. The
leading surge of moist and marginally unstable air will arrive on
Sunday, bringing a swath of showers and thunderstorms to the area
from south to north.

Low pressure developing in the central Plains on Sunday will lift
northeast along a slow moving cold front Sunday night through
Monday night. This system will generate periods of showers and
thunderstorms, and locally heavy rainfall, in an increasingly
moist (PWATs of 1.2 to 1.7 inches) and unstable air mass.
Probabilistic forecasts indicate a 30-60% chance of 1+ inch of
rain from Sunday through Monday night, with a 10-30% chance of 2+
inches. Potential for severe thunderstorms increases Sunday night,
as increasing elevated instability and steep mid-level lapse
rates (7-8.5 C/km) support a threat of large hail. Surface based
instability increases to 1500-2500 J/kg Monday afternoon and early
evening, leading to potential for surface-based severe
thunderstorms as the cold front approaches the forecast area.
Temperatures should remain above normal during this period.

Models have differing opinions on how quickly the cold front will
exit the region, with some as early as Monday night, and others
not until Tuesday night. Once the front clears the area, drier
weather and a return to near normal temperatures is expected
through the middle of next week.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1126 AM CDT Thu May 14 2026

High clouds will gradually increase from west to east through
this evening, with mid-level clouds and showers arriving in
north-central and central Wisconsin in the late evening, then
spreading east overnight. The showers will become less numerous as
they move into eastern Wisconsin, as a result of a weakening low-
level jet and a drier air mass. As the showers end, lower
ceilings will work their way in from the west Friday morning;
however, skies will start to scatter out at the same time as the
lower conditions work their way east.

Southeast to south winds will become a bit gusty later this
afternoon into tonight with gusts of 15-20 knots. LLWS is
expected to develop over north-central Wisconsin by late evening,
and spread southeast through the forecast area during the
overnight period. LLWS will then end Friday morning. South-
southwest surface winds of 15-25 knots are then expected on
Friday.

&&

.FIRE WEATHER...
Issued at 1254 PM CDT Thu May 14 2026

Pine fuels have reached their peak volatility and fine fuels have
still not greened up over northern Wisconsin, so periods of dry
and windy weather will bring elevated to near-critical fire
weather conditions through Saturday.

Very low relative humidity (20-30%) is expected through early this
evening; however, winds will only reach 8 to 15 mph.

A Red Flag Warning has been issued for Vilas County Friday
afternoon and early evening. There is some uncertainty concerning
the dryness of fuels in north-central Wisconsin, especially given
expected rainfall tonight. However, weather conditions should
reach critical levels, with highs near 80, relative humidities
around 25% and southwest winds 15 mph gusting to 25-30 mph.

Dry air remains across northern Wisconsin on Saturday, with
relative humidities dropping to 18-25% along with west winds 10
to 15 mph with gusts to 20 to 25 mph and highs around 80 degrees.
This will bring elevated fire weather conditions across much of
northern Wisconsin.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon to 9 PM CDT Friday for WIZ005.
&&

$$

DISCUSSION.....Kurimski
AVIATION.......Kurimski
FIRE WEATHER...Kurimski

NWS GRB Office Area Forecast Discussion