Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 250319

Area Forecast Discussion
National Weather Service Green Bay WI
1019 PM CDT MON OCT 24 2016

Updated aviation portion for 06Z TAF issuance

.SHORT TERM...Tonight and Tuesday
Issued at 331 PM CDT Mon Oct 24 2016


Quiet but cool conditions expected to continue tonight through most
of the day Tuesday. Mid-level ridge axis should slowly translate
across the Great Plains tonight, with a northwest flow regime
overhead this evening. 925 mb temperatures ranging between 0 to 3
degrees Celsius will lead to low temperatures in the upper 20s and
lower 30s across the forecast area. Winds are expected to stay light
overnight, enhancing radiational cooling, but also veer as the ridge
axis and surface high pressure moves through.

Clouds are expected to move in during the morning hours Tuesday and
continue to increase ahead of a mid-level shortwave, which should
bring our next best chances of precipitation Tuesday night into

.LONG TERM...Tuesday Night Through Monday
Issued at 331 PM CDT Mon Oct 24 2016

TUESDAY NIGHT AND WEDNESDAY... Forecast confidence is high.

A potent shortwave trough will track through the Upper Midwest and
western Great Lakes through Wednesday evening. The associated
surface low will track Iowa and northern Illinois, although the GFS
is farthest north with the track along the WI/IL border. The surface
warm front will remain well to our south as well. Expect blustery
east winds on Wednesday.

The 850-700mb frontogenesis and 500mb vorticity advection will lead
to a band of precip spreading into east central and northeast WI
from late Tue evening through the overnight hours. There will be dry
air in the low levels to overcome, but there is pretty high
confidence that forcing will be strong enough to get precip almost
up to the MI/WI border before 12Z Wed.

There could be a period of snow or snow mixed with rain in north
central WI from Rhinelander north late Tue night and early Wed
morning. Models are showing deep saturation with temperatures below
freezing just above the surface. This area has another shot of
snow/rain mix Wed evening as well.

The main forcing will push through the GRB forecast area Wed morning
and precipitable water values reach the 0.75 to 1 inch amounts. We
are looking at total rainfall amounts of around 1.5 inches toward
Oshkosh and Wisconsin Rapids to a half inch near the Michigan
border. Wednesday is going to be a raw fall day with highs in the
lower to mid 40s and blustery east winds.

THURSDAY... Forecast confidence is high.

Showers could linger through Thu morning due to cyclonic flow
lingering overhead. Clouds will remain through the day, leading to
max temps in the mid 40s to around 50. NW Winds will be a lot

FRIDAY THROUGH MONDAY...Forecast confidence is low.

The GFS and ECMWF remain at odds for Fri and the weekend in regard
to weather and temperatures. GFS is the wetter model for Fri and
then colder for the weekend. The Canadian model is showing somewhat
of a compromise between the two. Therefore, bumped up pops to likely
Fri afternoon with warm advection and vorticity advection ahead of
the next upper low approaching from the Northern Plains.

.AVIATION...for 06Z TAF Issuance
Issued at 1018 PM CDT Mon Oct 24 2016

A ridge of high pressure drifting over the region
will produce VFR Conditions tonight into Tuesday. A storm system
will bring rain and conditions deteriorating to IFR levels
starting Tuesday night.


Northwest winds will weaken overnight as high pressure moves into
the region which are also expected to veer to a northerly direction
tonight and northeast Tuesday morning. Waves expected to be between
1 to 2 feet over the nearshore.

East to southeast winds will likely reach Small Craft Advisory
levels, and possibly even Gale Warning criteria, by Wednesday
morning as low pressure tracks across Iowa and northern Illinois.



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