Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 191948
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
245 PM CDT FRI APR 19 2019

.SHORT TERM...

TONIGHT THROUGH SATURDAY NIGHT - Confidence...High.

Some gustiness will continue tnt into Sat over far se WI as
cyclogenesis occurs into the evening from TN nwd to ern KY and wrn
WV. The low will then occlude and fill late tnt-Sat. During this
time, the sfc ridge over MN will slowly move ewd across WI. As the
high moves ewd and an upper ridge builds, light sly winds will
develop Sat nt. The very dry airmass over srn WI will cool nicely
tnt as the high approaches, but warm into the middle to upper 60s
well inland on Sat. Low temps in the lower to middle 40s for Sat nt
with weak warm advection beginning.

SUNDAY THROUGH MONDAY - Confidence...Medium.

The trend continues for Sunday to be a very pleasant day across
southern Wisconsin.  A slowly sagging cold front will move across
northern Wisconsin during the day with pockets of low level warm air
advection focused in its vicinity, and also well to the southwest of
southern WI during the day.  Expecting breezing south to southwest
winds and warm 925H temps in the 16 to 18C range by the afternoon.
The low to mid levels of the atmosphere will remain dry, with only
some passing sct-bkn cirrus passing by from time to time. Hence
daytime temperatures should warm well into the 70s to around 80. The
pressure gradient will be weak enough to allow a lake breeze to
develop later in the morning and afternoon. Lakeshore areas in
Sheboygan and Ozaukee counties will be the coolest, longest, due to
the shore orientation.  Record high for both Madison and Milwaukee
is 84 for April 21st.

For Sunday night, expecting an increase in mid-high level clouds as
protective mid-level ridge shifts off to the east and increasing
south to southwest low level winds begin to pull deeper column
moisture into the area from the south.  Precipitable water increases
to around 1.25 inches on Monday ahead of approaching weak short wave
trof in the central and northern Plains.  Low level jet focus
remains to the south of WI Sunday night but a few showers and storms
may develop later on as forecast soundings show the elevated cap
weakening late in the night with MUCape of 500-1000 j/kg with weaker
low level convergence. There will be a better chance for showers and
storms later Monday into Monday night as low level jet reinvigorates
and brushes southern WI ahead of approaching deepening low pressure.
Guidance lacks agreement on this system for early next week, as
ECMWF has remained weaker and more progressive with an open wave
moving through Wisconsin Monday and Monday night, while GFS/NAM
slower with the main sfc low circulation moving slowly northeast
through WI on Tue. At this point, most favored time for convection
is later Monday into early Tuesday morning. Should still be mild on
Monday, and a bit more humid

.LONG TERM...

MONDAY NIGHT THROUGH FRIDAY...Forecast Confidence...Medium.

Differences continue in the Medium Range Guidance Monday night as
ECMWF and GEM remain more progressive with weaker, open wave moving
off to the east.  Meanwhile, GFS has a bit more amplitude and
corresponding slower eastward movement of the short wave, with the
chance for showers and storms continuing Monday night into Tuesday.
The GFS ensembles are showing large variability of the track and
timing of the passing associated surface low during this period, so
wl need to continue pops into Tuesday at this point.

Otherwise, guidance in general agreement on developing split flow
across the CONUS for the remainder of the work week with cut-off low
pressure developing over the southern Plains, while mild zonal flow
sets up over the northern CONUS.  After a slight cool-down on
Tuesday, daytime temperatures should rebound back into the 60s for
the final days of the week.  A weakening front passing through
the upper Midwest may bring a few showers to the area by Friday.

&&

.AVIATION(21Z TAFS)...Mostly clear skies and VFR conditions this
afternoon through Saturday night. Gusty nly winds will continue late
this afternoon especially over far se WI where wind gusts of 30-35
kts are expected. The brisk nly winds will weaken tonight but gust
to 25 kts over far se WI on Saturday.

&&

.MARINE...A Gale Warning continues for the south half of Lake MI
and the nearshore waters south of Port Washington into early this
evening. 8 to 12 foot waves occasionally to 16 feet can be expected
over the open waters and 5 to 8 feet over the nearshore waters. A
Small Craft Advisory is in effect for the same time period from Port
Washington to Sheboygan for brisk north winds and high waves. The
entire nearshore waters will need a Small Craft Advisory after the
Gale Warning expires for tnt-Sat for continued brisk nly winds and
high waves. Light winds and low wave heights are then expected for
late Saturday afternoon and Sunday.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Gale Warning until 7 PM CDT this evening for LMZ080-644>646-669-
     671-673-675-777-779-870-872-874-876-878.

     Small Craft Advisory until 7 PM CDT this evening for LMZ643.

$$
TONIGHT THROUGH SATURDAY NIGHT/AVIATION/MARINE...MG
SUNDAY THROUGH FRIDAY...MBK



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