Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 090533

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1133 PM CST Sun Dec 8 2019

.UPDATE...Patchy light DBZ showing up on KMKX WSR-88D but have yet
to see any drizzle reported at ASOS/AWOS. Did receive a report
from incoming employee of very light drizzle on windshield.
Expanding area of thicker clouds spreading north. Temps and dewpts
rising accordingly, but possibly some light drizzle may fall on
pavement that will be slightly below freezing. Fortunately, the
more expansive light precip should hold off until later tonight
allowing some time for pavement and surface temps to warm a bit.


.AVIATION(06Z TAFS)...MVFR ceilings spreading across southern WI,
and should overspread the area next several hours. Still expect
ceilings to lower to IFR as low level convergence increases
resulting in areas of light rain and drizzle developing. Temps in
the north may not have time to warm above freezing before the
light drizzle develops, which could result in a light glazing
later tonight. Pockets of dense fog may also develop late tonight
into Monday morning.


.PREV DISCUSSION... (Issued 931 PM CST Sun Dec 8 2019)

UPDATE...Clearing over the northern areas has allowed temps to
fall into the 25 to 30 degree range in some areas. Meanwhile,
farther south, temperatures remain in the mid 30s to around 40. As
the low level winds increase from the east to southeast, deeper
low level moisture should spread across southern WI during the
night. Along with the thickening clouds, temps should bounce back
into the 30s. The increasing convergence should also result in
areas of light rain and drizzle developing after midnight. Still a
concern that pavement and surface temperatures will be hovering
around freezing in the northwest areas including the WI Dells when
the light liquid precip begins late tonight or early Monday. Not
enough confidence at this point to post an Advisory, so will be
keeping a close eye on this potential through the late night.

MARINE...Winds will turn from the north to the east to northeast
overnight across the northern part of Lake Michigan, north of a
low pressure boundary setting up over the southern part of the
lake. Lighter south to southeast winds will persist over most of
the southern open waters. Gusty north to northwest winds can be
expected in the wake of passing low pressure later Monday into
Monday night.

PREV DISCUSSION... (Issued 557 PM CST Sun Dec 8 2019)

UPDATE...Increasing low level convergence along strengthening low
level trof and increasing low level moisture should result in
areas of light rain and drizzle developing overnight. Will need to
keep a close eye on pavement and low level temperatures overnight.
Partial clearing across the northern CWA has allowed temps to fall
into the low to mid 30s early this evening. Temps may even fall a
few more degrees before stabilizing and then increasing later in
the night as the deeper low level moisture pushes across the area.
Never the less, temperatures in the far north may remain around
freezing, increasing the threat for a period of light freezing
rain or drizzle that may affect the Monday morning commute. Expect
low clouds and areas of fog to accompany the light rain and
drizzle overnight.

AVIATION(00Z TAFS)...Expect low IFR ceilings to spread across
southern WI overnight along with areas of light rain and drizzle.
Fog will accompany the light precipitation. The fog could become
localized dense.

PREV DISCUSSION... (Issued 225 PM CST Sun Dec 8 2019)


Tonight - Confidence...Medium
A frontal boundary sagging southeast from northern WI will
gradually weaken somewhat, however as low pressure approaches from
the central Plains, there will be an increase in low level moist
advection with a lingering 850 baroclinic zone. Would expect
stratus/fog/drizzle to evolve later in the night. The meso models
show this with very light precipitation developing in the
southeast and then advancing north/northwest throughout the area.
By and large it looks like the cloud cover streaming northeast
should keep temps from falling off too much. The far northwest cwa
would be most vulnerable to any freezing potential very late in
the night and the confidence of this is too low to issue any
advisory at this juncture.

Monday and Monday night - Confidence...Medium
After the initial moisture surge there may be a lull in precip
for a time before the mid level energy and cold front bring
another round of precipitation. Low clouds/fog and perhaps some
drizzle will linger with broad surface/850 low in the area. As
colder air air works in there will be the potential for some mix
and then a change to all snow. Accums still look on the light side
with any amounts an inch or less and more towards the northern
portion of the forecast area during the afternoon and early
evening. Some drying in the dendritic growth zone may result in
some patchy freezing drizzle at times. Precipitaion will shift
quickly Monday evening with the cold advection on northwest winds
becoming prevalent.


Tuesday through Thursday Night - Confidence...High
A deep upper level trough will allow arctic air to impact the
area Tuesday through Wednesday night. Highs will mainly be in the
teens to low 20s with overnight lows in the single digits to near
zero towards central Wisconsin. Wind chills during this time will
single digits and teens during the day and below zero overnight.
Dry air will be in place with sunny skies until a shortwave moves
through northern Wisconsin Thursday. Some light snow will be
possible Thursday afternoon towards central Wisconsin but better
chances are farther north. Warmer temperatures are expected
Thursday with highs in the upper 20s to low 30s and wind chills in
the single digits to teens.

Friday through Sunday - Confidence...Medium
The pattern becomes more active in the extended with signs for a
few shortwave troughs moving through. There is some uncertainty
with the track and timing of these waves that could bring some
rain and snow to the area. Have some slight chances in for now.
Highs are expected to be in the mid to upper 30s with cooler
temperatures for Sunday as a cold front moves through.

AVIATION(21Z TAFS)...VFR conditions expected into early this
evening. High level cloudiness continues to stream wsw-ene. Lower
ceilings well to our northwest behind frontal boundary. Still
expecting light rain or drizzle to develop across the area esp
after 06z or so. Cigs/vsbys will be heading down as airmass continues
to moisten up, so some LIFR conditions are quite plausible very
late tonight into Monday. Precipitation will trend to a mix and
some light snow Monday afternoon into the early evening as colder
air wraps in behind a cold front with precip likely to wind down
rather quickly. With the loss of ice crystals during this time
some spotty freezing drizzle is possible as well.

MARINE...Pressure gradient slackening as trough approaches from
central WI. Gale warning has expired and will let the small craft
advisory do the same at 21z. Next focus will be the uptick in
winds on Monday evening in the wake of the cold front. Northwest
winds may gust high enough to warrant the need for a small craft
advisory Monday night, but at this time it looks as if the open
lake gusts would remain below gale criteria.




Tonight/Monday and Aviation/Marine...MBK
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