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000
FXUS63 KGRB 112352
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
652 PM CDT Thu Apr 11 2024

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- There is a chance of thunderstorms in central and north-central
  Wisconsin through this evening. Severe storms are not expected;
  however, some storms may produce gusty winds to 40 mph and small
  hail.

- There is a chance of thunderstorms Saturday night and at times early
  next week. Severe weather looks unlikely.

- Another potent system will move across the region Tuesday and
  Wednesday that could bring some locally heavy rain and
  thunderstorms. It is too early to determine if any of the storms
  would become severe.

&&

.DISCUSSION...
Issued at 302 PM CDT Thu Apr 11 2024

Short Term...Tonight and Friday

A mid level trough and attendant PV anomaly, seen on water vapor
imagery over southeastern MN, will track east through Wisconsin
through this evening. This will cause an uptick in showers and
thunderstorms as modest instability builds over western Wisconsin.
Any thunderstorms could produce gusty winds to 40 mph and small
hail as model soundings show an inverted-V sounding with steep low
level lapse rates. The biggest threat will be across central and
north-central Wisconsin closer to the most instability where some
sun has broken out at times. Further east the thunderstorm threat
will be lower as that area has been cloud covered for much of the
day with little to no instability.

Precipitation will end from west to east later tonight as the mid
level trough moves off to the east. Some showers will still be
possible across far north-central Wisconsin and the lakeshore
into Friday morning as another shortwave tracks through the region
with a bit better moisture lingering across these areas. Friday
afternoon is expected to be dry as high pressure builds across the
Mississippi Valley along with clearing skies as drier air advects
into the region.

Long Term...Friday Night Through Thursday

Tranquil conditions are expected Saturday as high pressure slides
east of the state. On Saturday night, a warm front will lift
northward across the area bringing a chance of showers and
thunderstorms. Bufkit soundings indicated several hundred J/KG,
steep mid level lapse rates and 20-30 knots of 0-6 km shear.
A few of the storms could produce small hail, the main
question is the placement of the shower and thunderstorm
activity.

It will be mild on Sunday with highs in the lower 60s to lower
70s. Tranquil conditions will continue Sunday night and Monday
with 500mb ridging across the western Great Lakes. Meanwhile,
a 500mb trough across the southwest United States will gradually
eject northeast Tuesday into Wednesday. Model tendencies are
to eject the system out too quickly, thus would expected a little
slower arrival of the rain in the coming days. Also, with
increasing easterly winds, clouds and rain would support a
lowering of high temperatures on Tuesday. Of interest,
the risk of severe weather is possible as the Day 6 outlook
from the Storm Prediction Center has a severe risk up to our
southwest border. That will be something to watch in the
coming days as the system approaches from the southwest.

There is potentially for some heavier rain in the Tuesday and
Wednesday period, especially with the thunderstorm activity.
A quick west-southwesterly flow will bring a continued chance
of showers on Thursday. Temperatures for much of the period
will run above normal.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 648 PM CDT Thu Apr 11 2024

A mid-level trough crossing the area will result in scattered
showers into the overnight hours with a few more showers lingering
over far northeast WI on Friday morning. VFR conditions will slowly
trend to MVFR overnight into Friday morning, before improving to
mainly VFR on Friday afternoon.

Light winds this evening will begin to stir overnight while shifting
to the northwest, though the strongest winds will remain just
aloft, so most sites will see increasing LLWS after 06z and lasting
through 12-13z. Once the LLWS ends on Friday morning, northwest
winds will become gusty with central to north-central sites gusting
to 25 kts while east-central sites see gusts to around 30 kts.

&&

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

&&

$$

DISCUSSION.....Kurimski/Eckberg
AVIATION.......JLA