259
FXUS63 KGRB 221104
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
604 AM CDT Wed May 22 2024

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Showers and thunderstorms possible at times today and Thursday,
  mainly across northern and central Wisconsin.

- Rivers over central Wisconsin may reach bankfull or even briefly
  surpass flood stage on Thursday.

- Better chance for widespread showers and thunderstorms Friday
  into Friday night.

&&

.DISCUSSION...
Issued at 316 AM CDT Wed May 22 2024

Short Term...Today...Tonight...and Thursday

A cold front and associated thunderstorms have pushed east of the
area early this morning. In their wake, some light scattered
showers and isolated thunderstorms will linger across the area
later this morning and into this afternoon as a mid level
shortwave tracks through the area with the best chances (20-30
percent) across north- central and central Wisconsin where the
best moisture will reside per model soundings. A tight pressure
gradient behind the cold front is causing gusty southwest winds
early this morning of 20 to 30 mph which should turn west-
southwest and gust to 25 to 35 mph later this morning into the
afternoon once deeper mixing is realized. Temperatures today are
only expected to get into the lower 60s across the north this
afternoon, with highs around 70 across central and east- central
Wisconsin.

Showers should dissipate this evening with the loss of daytime
heating along with surface winds, which could still gust to 10 to
15 mph overnight. Skies should clear tonight, allowing
temperatures to fall across the region. Lows tonight are expected
to range from the upper 40s across the north, to the lower 50s
across east- central Wisconsin.

Mostly sunny skies and warmer temperatures are expected across the
area on Thursday as a semi-stationary front develops across
northern Wisconsin and Upper Michigan. This frontal boundary could
be the focal point for light showers across the far north Thursday
afternoon (20 percent chance). Highs on Thursday are expected to
range from the lower 70s across the north, with upper 70s across
central and east-central Wisconsin.

Long Term...Thursday Night Through Tuesday

Main forecast challenges to focus on convective trends Friday
into Friday night and timing of additional precipitation chances
late in the weekend into early next week.

Another upper low/shortwave trough is forecast to swing from the
northern Plains through the Upper MS Valley and western Great
Lakes Friday into Friday night. Anticipate another round of
showers and thunderstorms to rotate through northeast WI with lift
from an associated cold front and forcing from the shortwave
trough. Severe threat looks minimal at the moment due to marginal
instability.

A progressive flow across the CONUS will bring two more shortwave
troughs across the Great Lakes late in the weekend into early next
week. Models are having some difficulty with the exact timing/
movement of both troughs. Therefore, confidence is still rather
low for timing of precipitation for the latter part of the holiday
weekend.

Temperatures are expected to be at or slightly below normal with
highs in the middle 60s to middle 70s.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 604 AM CDT Wed May 22 2024

Abundant cloud cover along with MVFR/IFR conditions will prevail
across the TAF sites this morning. Some light showers or sprinkles
are also possible, mainly west and north of the Fox Valley.
Conditions are expected to improve to VFR across the area this
afternoon as drier air advects into the region. Some showers could
linger across north-central and central Wisconsin this afternoon
as a shortwave tracks through the region. Skies should clear out
tonight and become VFR across all locations.

Surface winds will gust to 25-35 knots today, then ease overnight
to below 10 knots around midnight.

&&

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

&&

$$

DISCUSSION.....Kurimski/Kallas
AVIATION.......Kurimski