148
FXUS63 KGRB 171054
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
554 AM CDT Wed Jul 17 2024

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Below normal temperatures are expected today and tonight, then
  temperatures return closer to normal for the end of the week.

- Mainly dry weather is expected through Saturday morning. The
  next chance of showers and storms is on Saturday afternoon, with
  a continuing chance of afternoon showers and storms into the
  middle of next week. The risk of severe weather is low over the
  weekend, and uncertain next week.

&&

.DISCUSSION...
Issued at 357 AM CDT Wed Jul 17 2024

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

WV imagery showed a fairly potent short-wave trough moving through
NW WI early this morning, but a lack of moisture and instability
was limiting shower development, except over the bay and Door
County, where over-water instability was promoting scattered
thunderstorm development. North winds were pulling cooler
Canadian air into the region, and bringing an area of low clouds
into the MN Arrowhead and western Lake Superior. These low clouds
will likely impact at least NC WI this morning.

Precipitation Trends: The previously-mentioned short-wave will
sweep through the region early this morning, with additional
short-wave energy brushing far NE WI during the afternoon and
evening. Current thunderstorm activity over the bay/Door County
and isolated showers elsewhere will persist until the short-wave
moves out early this morning. Additional shower chances will
occur over far NC WI (Vilas and northern Forest/Oneida counties),
where NNW flow and lake-H8 delta-t`s up to 13 C will provide
lake-enhancement this morning through midday/early afternoon.
A few light showers may also form in eastern WI this afternoon.
Canadian high pressure brings dry conditions tonight into
Thursday.

Smoke trends...RAP/HRRR smoke models show less elevated smoke over
the region today/tonight than yesterday, and given that impacts
have been minimal to this point, will leave any mention out of
the forecast.

Temperatures & Humidity...Below normal temperatures and lower
humidity will prevail through Thursday, so air conditioners should
get a break for a couple days. Highs will be in the middle 60s to
middle 70s (along with NW-N winds gusting to around 20 mph) today,
and middle to upper 70s on Thursday. Lows tonight should be in the
40s to middle 50s. Dew points will be in the middle 40s to middle
50s; very comfortable for outdoor activities.

Long Term...Thursday Night Through Tuesday

Quiet weather at the start of the long term forecast, with a few
chances for showers and thunderstorms this weekend and early next
week.

High pressure keeps conditions dry, mostly sunny, and seasonable
on Friday. As the high slides east Friday night a weak surface
front is able to move down on Saturday. The front appears to stall
out, and then oscillate back north and south for a few days. This
boundary along with daytime instability will bring chances for
isolated to scattered showers and thunderstorms Saturday and
Sunday afternoons (mainly between Noon to 7PM). Anything that does
develop this weekend would likely be short-lived and non-severe.
Heavy rain concerns will also be quite minimal with a lack of deep
moisture. NBM probabilities show a roughly 20 to 40 percent
chance of any precip Saturday and Sunday, but less than 10 percent
chance to receive even a quarter inch at any given location.

This setup persists into early next week, but it is too early to
get a full grasp of severe potential.

Temperatures will generally be near normal through the forecast
period, with highs in the upper 70s and low 80s, and lows in the
50s to low 60s.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 542 AM CDT Wed Jul 17 2024

A short-wave trough and associated isolated showers will shift
east early this morning. Cool NNW winds flowing across Lake
Superior will produce lake-enhanced low clouds (MVFR ceilings)
and a few showers over north central and far northeast WI through
late morning/midday. Elsewhere, SCT-BKN cumulus (VFR, with
ceilings of 4-6K ft AGL) will occur during the late morning and
afternoon, and a few light showers may develop in eastern WI.
NW-N winds will gust to 15 to 20 knots during the late morning and
afternoon. Clouds will erode and winds diminish by early evening.

.KOSH...VFR conditions are expected today and tonight, with SCT-
BKN cumulus (bases of 4-5K ft AGL) developing in the late morning
and afternoon, then eroding by early evening. There is a very
small chance of showers in the afternoon, but confidence is
currently too low to mention in the TAF. North-northwest winds
will gust to 15-20 knots in the late morning and afternoon, then
diminish by sunset.

&&

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

&&

$$

DISCUSSION.....Kieckbusch/KLJ
AVIATION.......Kieckbusch