823
FXUS63 KGRB 152009
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
309 PM CDT Sun Sep 15 2024

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Dry weather and summer-like temperatures are expected this
  week. Highs will range from the upper 70s to middle 80s.

- The next chance of rain will not arrive until late this week or
  next weekend.

&&

.DISCUSSION...
Issued at 308 PM CDT Sun Sep 15 2024

Short Term...Tonight and Monday

Daytime heating led to the development of fair weather cu across
much of the forecast area away from Lake Michigan. A small
thunderstorm popped up in northern WI early this afternoon, and
then tracked northeast into the U.P. of Michigan. Rain-free
conditions have otherwise prevailed. There remains a very small
chance for isolated showers and thunderstorms in northern WI
through early evening. Large-scale forcing and moisture are
limited, but there is some instability that will last through
sunset, so maintained the small PoPs.

Temperatures have remained on track or a degree or two warmer in
spots. Waupaca and Wautoma are likely to be the warm spots of the
day at 89 degrees.

This evening, cu will dissipate and temps will start to drop, but
still remain mild overnight with lows in the upper 50s and lower
60s. The surface moisture and light winds may create some patchy
ground fog overnight, but this is expected to remain isolated with
little impact. High clouds streaming in from the south may move
overhead from time to time.

For Monday, with little change in the surface features and
airmass, expected similar conditions to today. Large-scale forcing
remains absent, but diurnally driven cu are likely to develop
with a very small chance of showers or thunderstorms in northern
Wisconsin. Afternoon high temps will reach the mid to upper 80s,
slightly cooler in the 70s near Lake Michigan.

Long Term...Monday Night Through Sunday

Warm and dry weather is expected through the week as an omega
blocking pattern emerges across the CONUS. There will be a trough
out to the west from the desert southwest to the northern Plains,
with a ridge from the southern Plains to the Great Lakes, and a
trough forming across the middle Atlantic states. The omega block
then tilts to the east late in the week into next weekend,
allowing the series of mid level disturbances in the trough out to
the west to edge towards the western Great Lakes region. The
first of these intrusions could bring some light rain to the
western portion of central and north-central Wisconsin as early as
Friday, with additional disturbances tracking through next
weekend. Despite the pattern inching eastward, there are signs
that most of the area could stay dry into next weekend as the
disturbances will be weak with the best moisture staying off to
the west. Therefore, there is a chance most or all of the area
could stay dry through next weekend unless the pattern shifts
further east. Given the difficulty in disposing of an omega
blocking pattern the drier solution seems mostly likely at this
point.

This pattern should yield warm and dry weather for much of the
extended period with highs ranging from the upper 70s to middle
80s. Some shallow ground fog will also be possible as higher dew
point air makes its way into the region. Lows will generally be in
the 50s with some 60 degree values possible across east-central
Wisconsin.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1231 PM CDT Sun Sep 15 2024

VFR flying conditions are expected through the TAF period. Some cu
has formed across northwest and north-central WI early this
afternoon, with bases around 4-5kft. have added a SCT cloud layer
to the KRHI, KAUW, and KCWA TAF sites through early evening to
account for this, otherwise just passing high clouds area-wide
from time to time. There is a small chance (<15%) some showers or
a non-severe thunderstorm could form out of the northern WI cu,
but potential for this is limited and coverage will be very
isolated, so have not include this in any TAF.

Quiet weather overnight into Monday morning. Winds will be less
than 10kts and from the S to SE through the TAF period. No
visibility restrictions are expected.

&&

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

&&

$$

DISCUSSION.....KLJ/Kurimski
AVIATION.......KLJ