Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 300900
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
400 AM CDT FRI SEP 30 2016
.TODAY AND TONIGHT...Forecast confidence high.
Stratus clouds have overspread srn WI along with a few showers over
far se WI. Additional rain showers over lower MI will be moving
across Lake MI and affecting far ern WI toward sunrise. A lobe of
PVA is currently pivoting wwd through the area and aiding the
development of the showers. PVA and moisture transport will increase
toward late afternoon and through the night as the upper low moves
nwd through IN tonight. PWs will increase to 1.4 inches and forecast
soundings do eventually saturate. Overall for today isolated to
scattered showers will prevail with rain becoming likely over ern WI
late in the day. Likely to categorical PoPs for tonight. Temps have
been mild early this morning but will not rise too much today given
the clouds and scattered showers.
.SATURDAY THROUGH SUNDAY NIGHT...Forecast Confidence Is Medium.
Models continue to show the closed 500 mb low shifting slowly
northward across northern Indiana Saturday, before moving into
southeast lower Michigan Saturday night. The closed low then
slides off to the east Sunday and Sunday night. There is a little
variation among the models with the exact 500 mb low track.
Several 500 mb vorticity maxima, with differential cyclonic
vorticity advection, should combine with decent column moisture to
result in a good shot at rain showers Saturday morning in the
eastern counties. This does continue into the afternoon. May need
to raise PoPs more for Saturday across the area, if the wet look
of the models continues.
There is some drying in the air column Saturday afternoon, which
may limit the areal coverage of any showers. Did not add thunder
for Saturday afternoon and evening in the far southeast counties,
as mean layer CAPE values are quite low.
Kept PoPs mainly in the eastern counties Saturday night into
Sunday morning, as the 500 mb low starts to push east of the area.
Weak high pressure should bring quiet weather for Sunday afternoon
and night, with drier air working into the area. Highs should
remain near seasonal normals, with mild lows.
.MONDAY THROUGH THURSDAY...Forecast Confidence Is Medium.
Dry southeasterly flow Monday into Tuesday night should bring a
period of quiet weather to the area. Temperatures may rise a bit
during this time, reaching the lower 70s inland on Tuesday.
Onshore winds should keep the coolest temperatures near the lake.
The next system should then move east into the region Wednesday
into Thursday. A fairly strong cold front is shown by the
ECMWF/GFS to move east into the region Wednesday night, exiting on
Thursday. This is accompanied by broad cyclonic flow at 500 mb, as
a deep 500 mb low remains over far northern Minnesota.
Area forecast soundings show rather weak instability Wednesday
afternoon and evening across the area. For now, will continue to
mention PoPs for showers and slight chances for thunderstorms
for Wednesday into Wednesday night, with showers lingering
Thursday. The mild temperatures should remain across the area.
.AVIATION/12Z TAFS/...Cigs of 1-3 kft this morning will continue to
drop to 600-900 feet and eventually 500 feet or lower as the more
steady rain arrives late today and tonight. Mvfr vsbys are expected
over ern WI with the rain this afternoon but the overall saturating
of the atmosphere will lead to widespread light fog and mvfr vsbys
tonight. Areas of 2sm br are possible.
.MARINE...A Small Craft Advisory continues until 09z Sat. Brisk nely
winds today will gradually weaken tonight into Sat. Thus high wave
heights of 4-6 feet will subside to 2-4 feet early Sat am.
LM...SMALL CRAFT ADVISORY until 4 AM CDT Saturday for LMZ643>646.
TODAY/TONIGHT AND AVIATION/MARINE...Gehring
Saturday THROUGH Thursday...Wood