Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 281140
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
640 AM CDT Fri Apr 28 2017
.AVIATION(12Z TAFS)...VFR conditions until middle to late
afternoon when rain arrives from the southwest. Areas of
1-3 kft Cigs and MVFR Vsbys late afternoon and evening
with the rainfall.
.PREV DISCUSSION... (Issued 339 AM CDT Fri Apr 28 2017)
Today and Tonight...Forecast Confidence is Medium.
A drier airmass approaching from the west will clear the stratus
this morning. Thus expecting a good amount of sunshine at least
for the morning hours. Middle to high clouds will then increase
from s-n in the early afternoon followed by light rain. The
shortwave trough over KS will track to nrn WI tnt along with a
modest 700 mb baroclinic zone. Thus light rain will spread from sw
WI through south central WI this afternoon. The light rain will
then spread to all of se WI by early evening with the rain
diminishing late. Increasing nely winds late tnt and cloud cover
will keep temps in the middle 30s to lower 40s so no frost
Saturday through Sunday night... Forecast confidence is medium.
There is a pretty good chance for dry, raw weather across
southern WI for much of Saturday. We need to wait for the next mid
level wave to reach the area for the rain. The 850-700mb theta-e
advection finally reaches southern WI by mid afternoon and
forcing should be enough to overcome any dry air in the mid
levels. There is very strong omega during this time period as
well. Brisk east winds and clouds will keep temperatures cool,
with highs in the mid 40s near the lake and lower 50s inland.
The 850mb warm front and mid level shortwave will push into
southern WI Saturday night. This is the time period where the
upper low that`s near the TX/OK panhandle takes on a negative tilt
which will give that elevated warm front a little extra push
northward. Winds will remain steady and strong out of the
northeast across southern WI since we will remain on the north
side of the surface front.
The shortwave energy will be split to the east and west of
southern WI on Sunday, but the nose of the low level jet will be
pointing right into northern IL. The steady feed of moisture and
lift along that 850mb warm front lead to off and on showers and a
few thunderstorms throughout the day, along with continued gusty
northeast winds. Instability is marginal and elevated, so no
Late Sunday afternoon and Sunday evening will bring our best
chance for moderate rain and scattered thunderstorms. This is the
time where the upper low gets into the Midwest, along with the
surface occluded front.
We`re looking at a good amount of rain for southeast WI this
weekend. Rain totals could be 2 to 3 inches for areas south and
east of Port Washington to Monroe. Several rivers in bankfull
will rise to minor flood stage.
Monday through Wednesday... Forecast confidence is medium.
The upper low will track right across Wisconsin on Monday, which
means that surface dry slot should bring a break in the rain
mainly Monday morning. The wrap- around region of the occluded
system is expected to swing across southern WI Monday afternoon
and evening. 850mb temps will be falling below freezing, so some
snow mixed into the rain is not out of the question for Mon
afternoon/evening before the system moves out. Winds will become
breezy out of the south on Monday, then veer west during the
Quiet and slightly warmer weather will return to southern WI on
Tuesday as that system gets out of the region. The next chance for
rain looks like it will hold off until Thu night.
MVFR ceilings will gradually rise to around 3.5 as skies clear,
especially south areas. Visibility should remain VFR. The next
chance for rain arrives this afternoon southwest of Madison then
across southern Wisconsin during the evening as cigs lower to
MVFR, with some IFR possible later tonight.
A Small Craft Advisory is in effect for Sat-Sun for
brisk nely winds and high waves. These conditions will occur due
to low pressure tracking from TX to IA during this time.
WI...Frost Advisory until 8 AM CDT this morning for WIZ056-057-062-
LM...Small Craft Advisory from 5 AM Saturday to 4 PM CDT Sunday for
Today/Tonight and Aviation/Marine...Gehring
Saturday THROUGH Thursday...Cronce