Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 191127
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
527 AM CST Sun Nov 19 2017

.UPDATE...Increasing subsidence and shifting of thermal trough is
allowing low clouds to continue to slowly erode from west to east
early this morning. Erosion will continue through mid-morning.
However mid-high clouds will stream into the area later today from
increasing upstream warm air advection.

&&

.AVIATION(12Z TAFS)...Low clouds continuing to slowly erode across
CWA. Clearing trend will reach eastern areas through mid-morning.
Then VFR conditions expected for the rest of the forecast period.
with a period of low level wind shear tonight.

&&

.PREV DISCUSSION... (Issued 247 AM CST Sun Nov 19 2017)

DISCUSSION...

TODAY and TONIGHT - Confidence...Medium to High.

Stratus continues to break up over western WI as subsidence and
drier air increases from the upper Midwest.  Expect this trend to
slowly continue eastward, but low clouds will be slower to clear in
the east due to lingering thermal trof in this area through 12Z. Low
clouds should become few-sct by later this morning in the east.
Upstream increasing warm air advection over northern Plains and
upper midwest will result in mid-high level clouds spreading across
southern WI this afternoon and evening before pushing off to the
east.  Cold air surge will weaken and become neutral this morning
with weak warm air return during the afternoon.  Despite the return
of some sunshine, a cold day lies ahead with lingering WNW winds and
daytime temps only rising to the low to mid 30s.  Daytime
temperatures will be at least 10 degrees warmer on Monday.

Monday - Confidence...Medium
Decent uptick in temps as gusty southwest winds pull in warmer
airmass with low pressure passing to our north. At the moment GFS
and NAM soundings show limited depth of mixing which keeps temps
from reaching full potential. Better mixing in combo with 925
technique would suggest we could get over 50.

Tuesday - Confidence...Medium
Cold front arrives in the morning with winds becoming gusty from
the northwest. 925 temps proggd to fall into negative territory
celsius. LLVL RH progs show an increase within the cold advection
regime typical of an establishing low level thermal trough.

Wednesday - Confidence...Medium
Looks like we get a break from the windy conditions as influence
of surface high passing to our south keeps pressure gradient
weaker across southern WI.

Thursday through Saturday - Confidence...Medium
Southwest winds kick back in ahead of another low pressure system
that will again pass to our north on Friday. Warmest day looks to
be on Friday as 850/925 temps increase within low level thermal
ridging ahead of the cold front. So could see temps scoot above
the Superblend guidance so trended in that direction. At this time
the ECMWF is the outlier showing precip on Friday. Decent
agreement that cold front arrives Friday night setting the stage
for a blustery Saturday.

AVIATION(09Z TAFS)...Expect MVFR cigs to gradually erode through
the morning as subsidence increases and thermal trof shifts off
to the east. VFR conditions then expected the rest of the day and
tonight. Increasing low level winds will result in low level wind
shear scenario tonight. Low level winds may reach 40 knots at 2kt
feet.

MARINE...Tug and multi-purpose vehicle in nearshore waters off
Sheboygan coast reported sustained winds around 23 knots after 06Z.
Gusty northwest winds due to strong low level cold air surge over
the relatively warmer lake waters.  The gusty winds will linger
through the day but gusts should subside later this morning and
afternoon to mostly below 22 knots.  Current Small Craft Advisory
runs through 18Z but may need to be extended into the afternoon as
wind gusts will still be into the lower 20 knot range.

Otherwise the winds will shift to the southwest tonight and pick up
once again later Monday into Monday night.  Gusts will likely reach
Small Craft Advisory levels Monday afternoon and continue through
Tuesday.  A few gusts will approach Gale levels Monday night ahead
of an approaching strong cold front.

&&

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

&&

$$

Update...MBK
Today/Tonight and Aviation/Marine...MBK
Monday THROUGH Saturday...Collar



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