549
FXUS63 KGRB 080838
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
338 AM CDT Wed May 8 2024

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- An unsettled weather pattern will bring intermittent chances of
  light rain from today through the weekend. There is a slight
  chance of thunderstorms over central and north-central Wisconsin
  this afternoon, but severe weather is not expected.

- Low temperatures in the lower to middle 30s will be conducive
  for a frost and freeze over north-central and far northeast
  Wisconsin on Thursday night.

&&

.DISCUSSION...
Issued at 338 AM CDT Wed May 8 2024

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

Precipitation trends and temperatures will be the main forecast
concerns during the short-term period.

An upper level low pressure system and mid-level frontogenetic
forcing will gradually shift out of far N/NE WI early this
morning, resulting in a gradual decrease in the rain band that
lingers there. Patchy fog in north central WI should mix out by
mid- morning. After a short dry period through midday, a few
showers and isolated thunderstorms may redevelop over the
southwest half of the forecast area, where an inverted surface
trough and weak instability (SBCAPE 100-400 j/kg) will reside in
the afternoon and early evening. Most of the shower activity
should wane after sunset, though isolated showers may linger over
the far southern part of the forecast area overnight. Models have
trended farther south with the next round of precipitation on
Thursday, so have lowered pops to slight chance/chance and
shifted precipitation chances a bit farther south. It`s possible
that further southward adjustments may be needed, due to dry NE
winds.

Persistent clouds over northern WI should hold temperatures in
the lower to middle 60s over northern WI today, while partly
cloudy skies and sunshine boosts highs into the lower to middle
70s farther south. Lows tonight should be in the upper 30s far
north to the 40s elsewhere. Mostly cloudy skies and brisk NE winds
(especially in the Fox Valley and lakeshore areas) will bring
cooler highs in the 50s to around 60 range on Thursday.

Long Term...Thursday Night Through Tuesday

Weather impacts in this part of the forecast mainly revolve around
frost potential and light precip chances.

Frost Potential:  Clouds will be departing Thursday evening from
north to south.  As the surface ridge axis arrives overnight, nearly
ideal radiational cooling conditions will be in place over central
to north-central Wisconsin.  Forecast low temperatures remain in the
lower to middle 30s over the sandy soil areas of north-central to
far northeast WI.  These temps will be favorable for frost
development.  Anyone with cold sensitive plants are advised to take
proper precautions.

A similar setup could be in store on Saturday night as well, as a
weak surface ridge axis is forecast to move into the region late.
Forecast temps are few degrees warmer than on Thursday night, but
MOS guidance indicates temps in the middle 30s are possible.

Light precip chances: A quick hitting clipper system remains on
track to bring rainfall to the region on Friday afternoon into
Saturday morning.  Decent dynamics combined with weak instability up
to 100 j/kg could lead to isolated storms and will leave a slight
chance of thunder in the forecast.  A tenth to a quarter inch of
precip appears possible for most locations.

Another quick hitting system could generate light rain on Sunday
afternoon and evening, but dynamics are not nearly as robust as on
Friday night.  Precip chances will therefore be lower.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1038 PM CDT Tue May 7 2024

Although thunderstorms have ended across the region, showers
continue at times as an upper level low tracks east of the region.
This activity should end from west to east early overnight,
leaving behind a mix of IFR/LIFR conditions across north-
central/central Wisconsin and a mix of MVFR/VFR across east-
central Wisconsin. In addition, showers are expected to continue
at times across north-central Wisconsin through early Wednesday
morning.

Flight conditions will eventually improve to VFR everywhere on
Wednesday as the low continues to track east. A low pressure
systempassing to the south Wednesday evening could bring some
showers to central and east-central Wisconsin; however, recent
model trends keep this activity away from the TAF sites.

&&

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

&&

$$

DISCUSSION.....Kieckbusch/MPC
AVIATION.......Kurimski