Scientific Forecaster Discussion
fxus63 kmkx 171401
Area forecast discussion
National Weather Service Milwaukee/Sullivan WI
901 am CDT Tue Sep 17 2019
The fog/stratus had been expanding northwest across the area, but
has since mostly stalled due to the warming sunshine. We should
see similar trends to yesterday, with things opening up by late
morning. Webcams look good, meaning this is more a low stratus vs
fog problem. The Lake Michigan shore will see the lower fog a bit
longer, but will still let the dense fog advisory expire at 10.
The rest of the day should be pleasant...no changes there.
The dense fog advisory will continue until about mid afternoon.
Expect a fairly stable weather pattern into Thursday. High
pressure from the Easter Great Lakes through New England will
combine with low pressure over the High Plains to bring a rather
persistent southeast to south flow into Saturday. Eventually, a
cold front will sweep across Lake Michigan Saturday night,
bringing westerly winds on Sunday.
Previous discussion... (issued 646 am CDT Tue Sep 17 2019)
expect areas of dense fog to impact the morning commute.
Have added Waukesha, Jefferson, and Walworth counties to the dense
fog advisory due to visibilities observed on traffic cameras and
reported observations. Expect fog to gradually lift this morning.
areas along Lake Michigan and a few counties inland continue to
see LIFR ceilings and visibilities. Expect these to linger over
the next few hours before improving to VFR by the late morning.
Expect light south to southeast winds through the day. Tonight
some patchy fog will be possible and may reduce visibilities to
MVFR mainly after 10z Wednesday.
Previous discussion... (issued 421 am CDT Tue Sep 17 2019)
Today through Wednesday...forecast confidence is high.
Expect fog to continue its grip over the lake counties with patchy
fog elsewhere. Remember to take it slow in reduced visibilities.
The fog is expected to lift by the late morning as we see some
daytime heating and start mixing out. Thanks to high pressure, pleasant
conditions with normal to above normal temperatures are expected
to continue for today into Wednesday. Southerly winds will help
US stay on the warmer side as well as keep our daytime dewpoints
in the 60s. Light winds and mostly clear skies tonight could cause
and additional round of patchy fog to develop but not as intense
as this morning.
Wednesday night through Friday night...forecast confidence
The upper ridge axis currently over WI will shift to the Ohio
River valley and lower Great Lakes for this period. Lgt sly winds
are warm temps will continue, while a front will stall over
portions of nrn and central WI. This will bring chances of showers
and tstorms mainly north and west of Madison with a dry forecast
for se WI.
Long term...the weekend and Monday...forecast confidence medium.
A fairly strong shortwave trough is expected to track from the
Great Plains into Canada but models have timing and placement
differences. The associated sfc low will bring a cold front
through srn WI either Sat or sun. Thus, have higher chances for
showers and tstorms this weekend. Drier air to arrive on Mon along
with weak high pressure.
Aviation 09z taf update...
expect LIFR ceilings and visibilities to continue this morning
mainly for sites in the the lake counties. Further inland some
MVFR ceilings and visibilities are possible as we head towards
dawn. Conditions will gradually improve has we head through the
morning with VFR conditions expected for all sites by the late
the dense fog advisory will continue until the late morning.
Conditions should gradually improve into the afternoon with winds
from the south to southeast into Wednesday. Expect winds to
increase over the open waters Wednesday into Wednesday night with
an front. The northern half of the lake could see southerly gusts
up to 25 knots. Lighter winds are expected Thursday.
WI...dense fog advisory until 10 am CDT this morning for wiz052-060-
Lm...dense fog advisory until 4 PM CDT this afternoon for lmz080-261-