000
FXUS63 KGRB 120302
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1002 PM CDT Thu Apr 11 2024

Updated aviation portion for 06Z TAF issuance

.UPDATE...
Issued at 855 PM CDT Thu Apr 11 2024

Last of any potential isolated thunderstorms are exiting
southward over portions of central WI while just a smattering of
showers remain over the rest of the forecast area. A bit more
concentrated area of showers dropping south from Upper Michigan
will impact northeast WI, including the Green Bay area, through
late evening. Rainfall amounts pretty light though, mainly a
hundredth or two at best. Rest of the night will feature just a
few lingering showers with main chances by daybreak shifted to
over far northeast WI. Winds tonight will not increase too much as
weak low-level inversion will keep majority of stronger winds
just off the deck.

Temperatures still mild late this evening will only slowly fall
off overnight with upper 30s possible very late far north-central
while solid low to mid 40s occur elsewhere.

&&

.KEY MESSAGES...

- Scattered showers taper off overnight, then end around daybreak
  Friday over far northeast Wisconsin. Becoming windy on Friday
  with northwest winds gusting to 35 mph over east-central
  Wisconsin.

- 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 06Z TAF Issuance
Issued at 958 PM CDT Thu Apr 11 2024

A mid-level trough crossing the area will result in scattered
showers into the overnight hours. VFR conditions will slowly
trend to MVFR overnight into Friday morning, before improving to
mainly VFR Friday afternoon and Friday evening.

Light winds 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
12-14z. 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.

&&

$$

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