Scientific Forecaster Discussion
fxus63 kmkx 181133
Area forecast discussion
National Weather Service Milwaukee/Sullivan WI
533 am CST Mon Nov 18 2019
No updates at this time.
LIFR ceilings over the eastern half of the state will gradually
improve this morning to MVFR. Visibilities will also increase
throughout the morning. Msn and westward may see a brief period of
VFR conditions around 00z before IFR ceilings return tonight. Snow
is expected to move in late tonight and transition to a wintry mix
Tuesday morning. There is some uncertainty with the track and
temperatures which would impact amounts. Currently expect snow
amounts under an inch with a slight chance for a light glaze of
Previous discussion... (issued 334 am CST Mon Nov 18 2019)
Today through Tuesday...forecast confidence is medium...
Clouds and reduced visibilities will linger this morning.
Temperatures are near freezing, so a few slick spots are possible
this morning. Visibilities are expected to improve throughout the
morning but the clouds will sadly remain throughout the day
keeping temperatures in the mid to upper 30s.
Tonight another quick hitting system will move through bringing
mainly snow at the onset and then transitioning to a wintry mix
throughout the morning as we lose cloud ice. Rain and drizzle
could create a light glaze of ice on surfaces with temperatures
around freezing. Snow amounts under an inch will be possible
before dry conditions return for the afternoon.
There is some uncertainty with the 500mb vorticity track of this
system. If follows the more westerly solution, expect lower
amounts. Temperatures also could be a few degrees warmer with the
cloud cover, this could also limit accumulations.
Wednesday through Thursday night...forecast confidence medium.
Low pressure will deepen across southeastern Colorado and
southwestern Kansas Wednesday, lifting into eastern Iowa by
Thursday morning. Highs Wednesday will warm to near average (low
to mid 40s). Rain will overspread the area Wednesday evening and
night, continuing into Thursday. It looks like much of the area
will see between a half and three quarters of an inch of rain
between late Wednesday evening and Thursday afternoon.
Current guidance is in pretty good agreement in bringing the
center of the surface low through southern Wisconsin during the
day Thursday. Highs Thursday will be tricky, with strong warm
advection ahead of the low being offset by widespread rain. It
does look like mid to upper 40s will be achievable for much of the
region, with perhaps a few spots across extreme southeastern
Wisconsin touching 50 degrees.
Once the low passes through, strong cold advection will take hold.
A few snowflakes are possible as precip comes to an end Thursday
afternoon, but right now it doesn't look to amount to much.
Temperatures will fall rapidly late Thursday afternoon into
Thursday night, with lows expected to bottom out in the mid 20s by
daybreak Friday. Given the amount of rain that is expected earlier
Thursday, we may need to watch for flash freeze potential late
Thursday night and early Friday morning.
Friday into the weekend...forecast confidence medium.
High pressure is expected to build into the area Friday, bringing
with it cool and quiet conditions. Northwest flow looks to stay in
place through the weekend, suggesting the below average
temperatures will stick around into (at least) next week.
Aviation 09z tafs...
Expect MVFR to LIFR ceilings to continue this morning with the
lowest ceilings over the eastern half of the state. Areas under
these lower ceilings are also seeing reduced visibilities of 1 to
4 miles. Conditions are expected to gradually improve to MVFR
across the area this morning but the low ceilings will remain
throughout the day.
Light winds will continue to shift to the west to northwest today.
Tonight expect winds to shift back to the southwest ahead of
another front expected to move through Tuesday evening, with west
winds continuing into Wednesday morning. A stronger system will
move through Wednesday night through Thursday. Gusty winds are
expected with this system and a Small Craft Advisory will likely
be needed for Thursday.