Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

FXUS63 KGRB 241942

Area Forecast Discussion
National Weather Service Green Bay WI
242 PM CDT TUE MAY 24 2016

Forecast discussion for routine afternoon forecast issuance

Issued at 238 PM CDT Tue May 24 2016

A much wetter weather pattern is settling in over the area.

The sharp upper ridge which brought a prolonged period of very
dry conditions to the area is now to our east, while an upstream
trough is located over the southwest United States. Southwest
upper flow between these features has become established across
the forecast area, and is likely to remain in place throughout the
forecast period.

The newly established pattern favors much wetter weather than it`s
predecessor. Though timing remains in doubt, several rounds of
showers and thunderstorms are likely during the period--resulting
in above normal precipitation. Daytime temperatures will vary
between normal and above normal depending on the amount of clouds
and precipitation. The increased humidity will keep overnight lows
well above normal.

.SHORT TERM...Tonight and Wednesday
Issued at 238 PM CDT Tue May 24 2016

Scattered showers and isolated thunderstorms continued across
north-central and northeast Wisconsin this afternoon. Some of
the stronger storms were producing gusty winds, locally heavy
rainfall and small hail.

A weak surface front will drop southward across the area late
this afternoon and tonight. Scattered showers and isolated
thunderstorms will come to an end this evening across much of the
area. Left a lingering chance of showers after midnight across the
south with the passage of the front. With 35 to 45 knots of wind
shear, still some heating of the day and boundary dropping south,
did not feel comfortable in removing the possibility of an
isolated severe storm.

For Wednesday, main problem is timing the arrival of the next
chance of showers and thunderstorms. Have trended slower from
previous forecast, but the midnight shift may need to slow it
down even more. High temperatures will again be on the warm side
if the rain arrives later in the day. The only exception will
be across eastern Wisconsin near Lake Michigan where an easterly
wind will keep it cooler. Not expecting any severe weather on

.LONG TERM...Wednesday Night Through Tuesday
Issued at 238 PM CDT Tue May 24 2016

Long-term forecast challenges continue to be the specifics of the
precipitation chances, and the risk of severe weather.

Typical forecast issues with southwest flow continue today.
Confidence is high that it is going to rain at times, and that
significant rainfalls will occur. But the details of when it will
rain remain elusive. Will continue to carry chance-likely PoPs
throughout the long-term portion of the forecast and hope we can
add additional resolution as each day shifts in the short-term
part of the forecast. Expect widespread 1 to 2 inch rainfalls
across the area during the next week, with some locations probably
getting over 3 inches.

The air mass across the area will become increasingly unstable as
gulf moisture arrives in the area. A marginal/limited severe
threat could develop during almost any of the long-term forecast
periods depending on the position of the main frontal boundary and
small scale shortwaves riding northeast in the upper flow. Much of
the medium range guidance shows a somewhat stronger/larger scale
shortwave crossing the region during the first half of the
upcoming weekend. If that feature evolves as now shown on the
guidance, it could lead to a more substantial risk for severe
weather when it arrives. Of course, that is still several days
away and a lot can change between now and then.

.AVIATION...for 18Z TAF Issuance
Issued at 1209 PM CDT Tue May 24 2016

A weak cold front will drop south across the area later this
afternoon and tonight. The front will bring scattered showers and
thunderstorms to much of the region this afternoon into this
evening. Some of the stronger storms could produce strong gusty
winds and hail. Later tonight, low clouds and fog are expected to
develop across much of the region. Any low clouds and fog should
burn off by 15z. Another round of showers and thunderstorms will
move across the area Wednesday afternoon and Wednesday night.



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