Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 161133
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
533 AM CST Thu Nov 16 2017

.UPDATE...

It`s a real struggle trying to figure out what this stratus will
do. The time of year dictates a pessimistic approach to clearing.
Yet, nearly all the guidance shows a rapid clearing toward late
morning. This happens as subsidence and dry air just rips a big
hole in the overcast and the clouds erode very quickly. I`m
pushing off the clearing a few hours, but will still go with some
sunshine this afternoon. The rest of the forecast remains on
track.

&&

.AVIATION(12Z TAFS)...

The MVFR stratus remains widespread across the region early this
morning, but is expected to gradually break up later this morning
with VFR conditions expected toward late morning. Exact trends
and timing are always difficult with stratus this time of year, so
confidence is a bit challenged with respect to cloud cover. Once
the MVFR CIGS scatter out, we will be VFR through the rest of the
TAF period.

Expect the northwest winds to steadily decrease this morning as
high pressure pushes in from the northwest. As the ridge slides to
the east this evening, look for winds to become very light, then
veer to the southeast. Warm air advection into the region on the
increasing southerly flow will bring a surge of mid and high level
clouds overnight.

&&

.PREV DISCUSSION... (Issued 242 AM CST Thu Nov 16 2017)

SHORT TERM...

Today and Tonight...Forecast confidence is high.

High pressure will slide across the area today, exiting to the
east by early evening. The main challenge for this period will be
with the behavior of the low clouds still streaming across the
area early this morning. We do see clearing approaching from the
north, likely bringing clearing skies first to Fond du
Lac/Sheboygan counties on south. The stratus will be tougher to
clear over the southwest forecast area. But, nearly all the
guidance does show the area clearing out toward mid day, so will
go with it. Subsidence with the ridge should rip expanding holes
in the shallow stratus this morning, so sunshine for the
afternoon.

As the ridge slides east tonight, we quickly get into a return
southerly flow and strong warm air advection. There is a lack of
deep moisture with this WAA, so just expecting an increase in
clouds with no precipitation. The low temp for tonight will
likely be reached in the evening, with temps then holding nearly
steady overnight.

LONG TERM...

Friday and Saturday...Forecast confidence is high:

Models continue to come into good agreement with the track of
strengthening low pressure late in the week. The low is expected
to pass by just south the the WI/IL border Friday night, heading
northeast into Ontario Saturday. Pretty good moisture surge with
this low, as precipitable water values will rise to around an
inch in the south. Plenty of lift to work with, so rain is a good
bet Friday into Saturday.

Held off on mixed precip most places Friday morning, as models
suggest temps should be warm enough for rain by the time
saturation is deep enough for precip. Most places should see a
little light rain by Friday afternoon, with the best chance for
widespread rain Friday evening into Saturday morning. Not out of
the question that the rain could mix with or change over to snow
for a time late Sat morning into the afternoon before the precip
comes to an end. Not expecting any accumulations though, as the
window of opportunity for snow will be short lived and any snow
that does fall will likely melt quickly.

Southerly winds ahead of the low will be breezy Friday, with even
stronger winds on the back side of the low Saturday.

Sunday through Wednesday...Forecast confidence is high:

High pressure will be in place for much of the time during the
first half of next week. Models do bring a wave through Monday
night or early Tuesday, but went with a dry forecast due to
limited available moisture.

Temps are expected to be chilly Sunday behind the departing low,
but then will likely recover nicely on Monday with temps
approaching or hitting the 50 degree mark. Cooler temps will
return for mid-week behind the departing trough.

AVIATION(09Z TAFS)...

The MVFR stratus that is widespread across the region early this
morning is expected to gradually break up this morning with VFR
conditions expected toward late morning. The clearing should work
down the southeast counties first, from Fond du Lac, south toward
Milwaukee. It will likely hang on longer in the KMSN area. Exact
trends and timing are always difficult with stratus this time of
year, so confidence is a bit challenged with respect to cloud
cover. Once the MVFR CIGS scatter out, we will be VFR through the
rest of the rest of the TAF period.

Expect the northwest winds to steadily decrease this morning as
high pressure pushes in from the northwest. As the ridge slides to
the east this evening, look for winds to become very light, then
veer to the southeast. Warm air advection into the region on the
increasing southerly flow will bring a surge of mid and high level
clouds overnight.

MARINE...

The small craft advisory remains in effect until noon. The gusty
northwest winds will gradually diminish today as high pressure
approaches from the northwest. Southerly winds will increase again
late tonight into Friday with another small craft advisory likely
for Friday through Friday evening.

Strong northwest winds are expected in the wake of a passing cold
front on Saturday. Gale force winds are possible Saturday
afternoon into Saturday evening. Small craft advisory conditions
would then likely stretch into early Sunday afternoon.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory until noon CST today for LMZ643>646.

&&

$$

Update...Davis
Today/Tonight and Aviation/Marine...Davis
Friday THROUGH Wednesday...DDV



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