Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 061923

Area Forecast Discussion
National Weather Service Green Bay WI
223 PM CDT Wed Jul 6 2022

Forecast discussion for routine afternoon forecast issuance

.SHORT TERM...Tonight and Thursday
Issued at 222 PM CDT Wed Jul 6 2022

Cool east flow off Lake Michigan and lingering low level moisture
was supporting abundant stratocumulus across the forecast area
this afternoon, though some clearing was noted near the lakeshore.
Temperatures were below normal, ranging from the upper 60s near
the lakeshore to the lower to middle 70s inland.

Canadian high pressure will sag south into the region tonight,
bringing dry weather and partly cloudy skies. There could be some
patchy ground fog overnight, but not expecting any major impacts.
Lows should be in the middle 50s to lower 60s.

On Thursday, a weak cold front will sag into northern WI during
the afternoon, and provide the focus for scattered showers and
thunderstorms. Farther south, daytime heating and CAPE of 250-500
j/kg will support isolated showers and storms. Weak short-wave
energy is expected to pass mainly to our south. High temperatures
should range from the lower to middle 70s lakeside to the upper
70s and lower 80s inland.

.LONG TERM...Thursday Night Through Wednesday
Issued at 222 PM CDT Wed Jul 6 2022

Mean flow across the CONUS is expected to amplify into the weekend
as an upper ridge builds over the High Plains and upper troughs
develop over the Pacific Northwest and eastern CONUS. This
amplification will be short-lived as the ridge breaks down by
Sunday, allowing the Pacific Northwest upper trough to push east
across the U.S.-Canadian border. This trough is forecast to deepen
over the Great Lakes early next week, thus increasing chances for
precipitation Sunday night through Tuesday. Temperatures appear to
be close to normal through the extended period.

Thursday night and Friday...
Still cannot completely rule out scattered showers Thursday night
as a weak frontal boundary drops south through the area. A much
better chance for showers/storms to reside well to our south along
a quasi-stationary front over IA/central IL. Otherwise, mostly
cloudy skies are expected with dew points dropping into the 50s
behind the cold front. Min temperatures to range from the lower to
middle 50s over far northern WI, to the lower 60s south. High
pressure over Ontario is forecast to drop south into the Great
Lakes on Friday and bring more sunshine back to northeast WI.
East-northeast winds will bring slightly below normal temperatures
and comfortable dew points to the area. Look for max temperatures
Friday to be in the lower 70s near Lake MI, middle to upper 70s

Friday night and Saturday...
While dry conditions to continue through Friday night with high
pressure in control, temperatures may be a be tricky depending on
how much cloud cover exists as shortwaves top the High Plains
upper ridge and slide southeast into the northern Plains/Upper
Midwest. If skies do remain mostly clear, temperatures across the
Northwoods could drop into the middle to upper 40s, while lower to
middle 50s would be expected south. This high pressure will remain
parked over the Great Lakes through Saturday, keeping enough dry
air in place to keep any moisture from shortwave energy to our
west. Despite the cool start to the day, temperatures should
quickly recover with strong July sunshine. This would bring
readings into the lower to middle 70s near Lake MI, upper 70s to
around 80 degrees inland.

Saturday night and Sunday...
The high pressure will finally begin to pull east Saturday night,
allowing for return flow to develop over WI by Sunday. The upper
ridge over the High Plains breaks down during the latter half of
the weekend and allows the Pacific Northwest upper trough to move
east into the northern Plains/Upper MS Valley by Sunday afternoon.
Anticipate some increase in clouds on Sunday with a minimal chance
of showers/thunderstorms to reach central WI later in the day. Max
temperatures Sunday to be in the middle to upper 70s lakeside,
upper 70s to lower 80s inland.

Sunday night and Monday...
This shortwave trough (and its attendant cold front) will reach
the Great Lakes Sunday night, bringing the region its next best
chance of seeing showers/thunderstorms. The chance for additional
showers and storms would continue through Monday as additional
shortwaves move through the trough situated overhead. Too early
yet to determine severe potential as cloud cover would be a big
determining factor on amount of instability. If we can get some
sunshine, CAPE values could reach 1K J/KG over central/east-
central WI with 0-6km shear of 35 to 45 knots. Something to watch
in the coming days. Max temperatures for Monday to be in the upper
70s to middle 80s.

Monday night and Tuesday...
The unsettled weather pattern looks to persist through Tuesday as
a new upper ridge builds over the Rockies and the downstream upper
trough strengthens over the Great Lakes/New England states. While
precipitation chances may diminish a bit Monday night (loss of
daytime heating), there will be another uptick on Tuesday as
instability increases and other embedded shortwaves move through
the upper trough. Max temperatures Tuesday to be in the middle 70s
to lower 80s.

Tuesday night and Wednesday...
Even though the upper trough shifts east, enough of a lingering
cyclonic flow over the region may bring a few showers into
Wednesday. Despite a north-northwest flow into WI, max
temperatures are forecast to be near normal with more middle 70s
to lower 80s expected.

.AVIATION...for 18Z TAF Issuance
Issued at 1240 PM CDT Wed Jul 6 2022

Though partial clearing has occurred in some areas, most locations
were still reporting MVFR ceilings across the CWA early this
afternoon. Expect a gradual clearing trend later this afternoon
and early evening, with ceilings slowly rising into the VFR
category before the clearing arrives. We could see patchy ground
fog over the area, though confidence is not high enough to include
in the TAFs at this time. Expect cumulus clouds to increase again
due to daytime heating later Thursday morning.

East winds will become light and variable tonight, then turn
south to southwest later Thursday morning.



SHORT TERM.....Kieckbusch
LONG TERM......Kallas
AVIATION.......Kieckbusch is the U.S. government's official web portal to all federal, state and local government web resources and services.