Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 241209 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
709 AM CDT Sat Jun 24 2017

.UPDATE...


&&

.AVIATION(12Z TAFS)...

VFR conditions are expected through the TAF period. A few showers
are possible by midday, but a mid level shortwave pushing into
the area late this afternoon will bring more widespread showers
and scattered thunderstorms to south central WI through early
evening. Shower chances diminish as these showers spread east
toward sunset.

&&

.PREV DISCUSSION... (Issued 327 AM CDT Sat Jun 24 2017)

TODAY AND TONIGHT...Forecast Confidence Is High.

We can expect another day with diurnal cumulus clouds, scattered
showers and even some thunderstorms today. This is due to cyclonic
flow aloft and an approaching shortwave trough. This shortwave is
more potent than the one that went through yesterday. It will
arrive during the late afternoon hours, so added a period of
likely showers and chance of thunderstorms for primarily south
central WI.

By the time it reaches southeast WI, we will be losing the
daytime heating, so there is just not as high of a chance for the
showers/storms. Winds will be gusty out of the west once again.

Plan on clearing skies for the overnight hours. Look for
temperatures to drop down to around 50.

SUNDAY THROUGH MONDAY NIGHT...Forecast Confidence Is Medium.

Models are in decent agreement with showing several 500 mb
vorticity maxima shifting southeastward through the area Sunday
into Monday. This is within a broad 500 mb trough axis lingering
across the region. Subsequent upward vertical motion from
differential cyclonic vorticity advection is expected. Area
forecast soundings are showing steep low and middle level lapse
rates during this time, with cold 500 mb temperatures.

This results tall and skinny but weak mean layer CAPE by each
afternoon period. This should support chances for showers during
this time, with small chances for thunderstorms Sunday and Monday
afternoon. High pressure should then bring quiet weather for
Monday night.

Steady cold air advection on west to northwest winds Sunday into
Monday will keep temperatures unseasonably cool. Highs should
only reach the middle to upper 60s. Lows should drop into the
upper 40s to lower 50s Sunday night and Monday night.

TUESDAY THROUGH FRIDAY...Forecast Confidence Is Medium.

Models continue to show high pressure sliding to the southeast of
the area Tuesday into Tuesday night. This should bring quiet
weather to the area. Warm air advection during this time should
begin to bring more seasonable temperatures into the area.

Models then show 500 mb flow becoming more zonal Wednesday into
Friday. This allows for an elongated 500 mb vorticity maximum to
push east through the region Wednesday. Warm air advection in the
low levels also brings warmer and more humid air into the region
Wednesday into Wednesday night. Area forecast soundings from GFS
show some elevated and mean layer CAPE at times. Continued to
bring likely PoPs west to east across the area Wednesday afternoon
into Wednesday night.

Kept PoPs going for Thursday into Friday, as GFS/ECMWF show
another low moving northeast either through of just south of the
area. Both models have a decent amount of QPF with this system. We
will see if this track continues in later model runs. Warm and
humid conditions should remain over the region.

AVIATION(09Z TAFS)...

VFR conditions are expected through the TAF period. A few showers
are possible by midday, but a mid level shortwave pushing into
the area late this afternoon will bring more widespread showers
and scattered thunderstorms to south central WI through early
evening. Shower chances diminish as these showers spread east
toward sunset.

MARINE...

Winds will be persistently out of the west the next few days, but
should remain below Small Craft Advisory levels. The westerly
flow will keep waves close to shore below 1 foot.

&&

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

$$

Update...99
Today/Tonight and Aviation/Marine...Cronce
Sunday THROUGH Friday...Wood



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