Area Forecast Discussion
Issued by NWS Green Bay, WI

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142
FXUS63 KGRB 231656
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1156 AM CDT FRI SEP 23 2016

Updated aviation portion for 18Z TAF issuance

.SHORT TERM...Today...Tonight...and Saturday
Issued at 348 AM CDT Fri Sep 23 2016

Latest surface analysis shows a cold front has settled south
across northern Illinois early this morning. This front is
forecast to remain well to our south today and tonight, before
lifting back north on Friday as a warm front across the upper
Mississippi Valley.

The passage of the cold front will mark a return to temperatures
around normal for this time of year, as well as a well needed
break from heavy rain. Despite the break from heavy rain, there
will still be chances of rain during this period. Today some weak
mid level frontogenesis will bring the chance for showers across
the far southern cwa. Given the lift will be weak, chances will be
low today. Some dry air advecting in across the north could break
some sun out near the Michigan border, with areas that manage to
break out in sun climbing close to 70 degrees.

Small rain chances will continue tonight and Friday morning as the
aforementioned front lifts north across the Mississippi Valley as
weak isentropic lift is noted across the southern and western cwa.
Limited instability during this period will preclude the mention
of thunder during this period, as only showers are expected.

.LONG TERM...Saturday Night Through Thursday
Issued at 348 AM CDT Fri Sep 23 2016

500mb trough across the western United States will eject
northeast out of the Rockies into the northern plains on Saturday,
then into Ontario Sunday night. At the surface, a deepening low
pressure system will move into Canada Sunday morning with
associated cold front approaching the state. This system will
bring another round of rain to the region.

Preferred the ECMWF solution which would bring a chance of rain
into our western counties late Saturday night. Went with likely
chances of rain across the west Sunday morning, and then likely
chances across the east Sunday afternoon. The rain will linger
into the evening across eastern Wisconsin. There will be a break
in the rain Sunday night, but cool cyclonic flow will bring a
chance of showers later Sunday night across the north, and across
the entire area on Monday into Tuesday. Dry conditions will
prevail Wednesday and Thursday. Only minor changes made to
max/min temperatures.
&&

.AVIATION...for 18Z TAF Issuance
Issued at 1100 AM CDT Fri Sep 23 2016

Current MVFR clouds in east central Wisconsin should rise to VFR
levels later this afternoon. Otherwise, skies will range from
mostly sunny north to partly to mostly cloudy in central and
eastern Wisconsin. Removed PoPs for this afternoon since there is
very little in the way of forcing and moisture is decreasing
across the area.

Quiet conditions will continue overnight with high clouds
scattering out for a time. However, a front approaching from the
west will bring cloud cover back in Saturday morning from west to
east. Fairly confident cigs will lower to MVFR levels, with IFR
cigs possible, mainly in central Wisconsin. Showers may also work
their way into cental and east central Wisconsin later Saturday
morning or early afternoon, however low confidence at this time
and left rain chances out of the TAFs for now. If showers do
develop, rain should remain light.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....Kurimski
LONG TERM......Eckberg
AVIATION.......Allen



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