Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 141143 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
543 AM CST Wed Feb 14 2018

.UPDATE...

Having some trouble getting a handle on the thin low stratus and
fog potential tonight across the area. Forecast soundings have
been showing a thin layer of low stratus clouds gradually moving
into the area from the south into this evening. There may be
breaks in this thin low cloud deck. There is also some advection
fog that could develop as well, with the milder air moving over
the snowpack.

Think that some of these low clouds should move into southern and
eastern portions of the area by early this evening. The gusty
winds possible overnight in eastern parts of the area may limit
the fog potential. However, advection fog over the snowpack may
not get mixed out much. For now, kept patchy fog over most of the
area by later tonight, with areas of fog in the far southern
counties.

Wood

&&

.AVIATION(12Z TAFS)...

Low level wind shear will continue until around 14Z this morning,
with southwest winds at 2000 feet above ground level around 35
knots. These winds will weaken as the morning goes on. Expect
south southwest winds gusting up to 20 knots near Lake Michigan
this afternoon into this evening, with lower gusts inland.

Clear skies this morning should gradually give way to some thin
low stratus clouds moving into southern and eastern portions of
the area tonight. Some fog is expected to move into the area as
well, mainly later tonight.

There is uncertainty with how widespread any low ceilings will
be, as well as how low visibility values will get. There may be
some breaks in the thin low stratus as well. Could see ceilings
around 1000 feet in southern and eastern portions of the area,
with visibility values down to 1 to 2 miles in southern portions
of the area.

Wood

&&

.PREV DISCUSSION... (Issued 334 AM CST Wed Feb 14 2018)

SHORT TERM...
Today And Tonight...Forecast Confidence Is Medium.

Warm air advection is expected today across the area, which will
bring milder temperatures into the area. Given the snowpack over
the area, highs will be tempered somewhat, so went near short term
model blended values in the upper 30s to lower 40s.

There is the possibility of an area of thin low stratus clouds to
move into southern and eastern portions of the area this evening,
lingering later tonight. There also is fog potential as well, with
the warmer air moving over the snowpack. There is uncertainty here
with these occurring. There could be breaks in the thin low
stratus clouds, and gusty boundary layer winds and limited low
layer moisture may limit the extent of the fog.

For now, brought in the thin low stratus to the southern and
eastern portions of the area tonight. There should be some fog
development mainly later tonight, especially in the far south and
southwest, closest to where it should advect from. Lows tonight
should not drop a whole lot, especially if any thin low stratus
clouds lingers.

LONG TERM...
Thursday - confidence medium

Soundings show a saturated shallow layer at the surface into
Thursday morning. There is a very dry air aloft and winds are
elevated off the deck. So will have mention of patchy fog and low
stratus. However, surface winds wind down during at this time,
especially in the southwest so will have to watch if advection
fog creates for more of a problem. Later Thursday winds become
northwest bringing in some drier air mitigating fog potential
later in the day. The upper jet strengthens over the region on
Thursday within southwest flow aloft. Low pressure passes by to
the south of the state and there is a small chance of light rain
clipping the southeast. There is a small chance for some light snow
showers Thursday night as a shortwave moves through. Little, if
any accumulation.

Friday through Wednesday- confidence high

Northwest winds ramps up on Friday as high pressure sinks into
the plains. An upper trough drops through bringing colder temps
Friday and Saturday. The highs slides across the region Friday
night and with clear skies lows will be in the single digits. A
surface and upper trough moves through on Saturday with a warm air
advection regime and a chance for light snow.

The GFS and ECMWF are showing an active pattern for early next
week. Temperatures bounce around the freezing mark depending on
the time of day so there are chances for rain and snow.

AVIATION(09Z TAFS)...

Low level wind shear will continue into about the middle morning
hours across the area, with southwest winds at 2000 feet above
ground level around 40 knots. These winds will weaken as the
morning goes on.

Expect south southwest winds gusting up to 20 knots near Lake
Michigan today, with lower gusts inland. Clear skies this morning
should gradually give way to some thin low stratus clouds moving
into southern and eastern portions of the area early this evening
and into tonight. Some fog is expected as well, mainly later
tonight.

There is some uncertainty with how widespread any low ceilings
will be, as well as how low visibility values will get. There may
be some breaks in the thin low stratus as well. Could see
ceilings around 1000 feet with visibility values down to 1 to 2
miles, mainly in the southern and eastern portions of the area.

MARINE...

Will cancel the Small Craft Advisory early, as winds are well
below criteria across the area. South southwest winds are expected
to gust to near 22 knots at times today into tonight, with higher
winds toward 1000 feet above the surface and still below the
inversion. However, think that this is a borderline situation for
a Small Craft Advisory. MODIS imagery from Tuesday shows that most
of the nearshore waters are covered in ice. Thus, any wave action
will be limited, given the offshore flow.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

$$

Update...Wood
Today/Tonight and Aviation/Marine...Marquardt
Thursday THROUGH Tuesday...Wood



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