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000
FXUS63 KGRB 210848
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
348 AM CDT Sun Apr 21 2024

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Elevated fire weather conditions are likely this afternoon and
  Monday afternoon due to relative humidities ranging from 20 to
  30 percent and winds of 15 to 25 mph.

- Precipitation chances return Monday evening through Tuesday. A
  few thunderstorms are possible Tuesday afternoon, but severe
  weather is not expected.

&&

.DISCUSSION...
Issued at 347 AM CDT Sun Apr 21 2024

Short Term...Today...Tonight...and Monday

After a cool start to the morning, mostly sunny skies will allow
temperatures to warm throughout the day. Deep mixing up to 700-800
mb will bring winds of 10 to 20 mph with some gusts to 25 mph to
the surface along with low relative humidity values of 20 to 30
percent during the afternoon. The wind gusts and dry air will
cause elevated fire weather conditions through the early evening
hours. Highs today are expected to range from the lower to middle
50s across the north, to around 60 across the Fox Valley as well
as portions of central and northeast Wisconsin away from the lake.

Light winds and mostly clear conditions will provide for ideal
radiational cooling conditions tonight. This will allow
temperatures to plummet across the normal cold spots across
north-central and central Wisconsin. Lows tonight are expected to
range from the lower to middle 20s across the cold spots in
north-central Wisconsin, with lower to middle 30s across east-
central Wisconsin and the lakeshore.

Monday will start out mostly sunny in the morning, with increasing
clouds during the afternoon as a cold front approaches the upper
Mississippi Valley. Although the boundary layer will be a bit more
shallow on Monday, around 800 to 850 mb, a tighter pressure
gradient will bring blustery conditions to the area (15 to 25 mph
with some gusts to 35 mph). In addition, although dew points will
be a bit higher, warmer temperatures will keep relative
humidities in the middle to upper 20s during the afternoon.
Although today will be an elevated fire weather day, Monday is
looking like the more critical day with the higher winds and
warmer temperatures. The approaching cold front could bring a
chance (20-30 percent) for rain showers to western portions of
central and north-central Wisconsin late Monday afternoon;
however, the abundant dry air in place may hold this precipitation
off until Monday evening. Highs on Monday are expected to rise
into the lower to middle 60s.

Long Term...Monday Night Through Saturday

A quick one-to-two punch of a system is still on track to impact the
region Monday evening through late Tuesday. A cold front moving from
west to east will provide the first chance for rain showers Monday
evening. Precip amounts during this time have decreased from the
previous forecast as forecast soundings indicate lingering low-level
dry air from the departing high pressure system. Scattered rain
showers will likely be the outcome, but gusty winds may accompany
the showers as an impressive 40-50kt low-level jet will be overhead.

A small lull in the precip will likely occur sometime late Monday
night or early Tuesday morning before the next chance for rain drops
from the northwest, associated with a robust shortwave trough. The
precip should hold off until midday Tuesday and quickly drop
southeast across the forecast area, exiting by mid-evening Tuesday.
Thunderstorms will be possible during this time with MUCAPE around
300-600 J/kg and mid-level lapse rates around 7.5 C/km. Some of the
thunderstorms may produce strong wind gusts as forecast soundings
show an inverted-V, but the overall potential for severe weather is
low. Cold air will quickly filter into the region on the back side
of the precip, which may allow some snow or graupel to mix in as
well.

Dry conditions return for Wednesday and Thursday as high pressure
and ridging build overhead. The next chance for precip moves across
the area Friday into Saturday, with a southern stream system. Given
its origin, Gulf moisture and warmer air may bring the potential for
thunderstorms and above normal temperatures.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1007 PM CDT Sat Apr 20 2024

Stratocumulus clouds should be east of the region by issuance
time, with only patchy mid/high clouds expected overnight. SCT-
BKN high-based cumulus clouds are expected to form during the
late morning and afternoon on Sunday, then dissipate in the
evening. Light west winds are anticipated overnight, with gusty
WNW winds picking up in the late morning and afternoon Sunday,
before diminishing again around sunset.

&&

.FIRE WEATHER...
Issued at 347 AM CDT Sun Apr 21 2024

Moderating temperatures and a dry airmass will lead to elevated
fire weather days today and Monday. Winds will be a little
stronger on Monday compared to today with sustained values of 15-
25 mph and gusts up to 35 mph (sustained winds 10-20 mph with
gusts to 25 mph today). In addition, minimum relative humidities
will fall to 20 to 30 percent today and Monday. While elevated
fire weather conditions will be present each day, concern is a
little higher on Monday due to slightly stronger winds and warmer
surface temperatures.

Another period of elevated fire weather conditions is possible
Wednesday and Thursday, as a dry airmass moves into the region.
However, winds will be below critical levels due to the proximity
of a prevailing high pressure system.

&&

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

&&

$$

DISCUSSION.....Kurimski/Kruk
AVIATION.......Kieckbusch
FIRE WEATHER...Kurimski/Kruk