Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 172334
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
634 PM CDT Mon Apr 17 2017
.AVIATION(00Z TAFS)...Back door cold front has progressed into
south central WI early this evening. Winds have switched to the
east in Madison, and boundary should be moving through Monroe,
Mineral Point and Sauk City areas with the next 1-2 hours.
Scattered light sprinkles have pushed off to the east so dry and
quiet conditions are expected through most of tomorrow. Cirrus
clouds should eventually return to the area later tonight.
Winds may be a bit stronger on Tuesday ahead of approaching weak
cold front. May see some gusts to 30 to 35 knots from late morning
through the afternoon, especially farther away from Lake Michigan.
.PREV DISCUSSION... (Issued 335 PM CDT Mon Apr 17 2017)
TONIGHT - Confidence...Medium
Surface low in sw WI with inverted trough axis into ne WI is
proggd to get wiped out with time as influence of high to the
north becomes dominant. 88-d showing the lake boundary making
steady westward progress through srn WI. Good deal of high based
cu that should gradually dissipate as the evening wears on with
plenty of clear air upstream.
TUESDAY - Confidence...Medium
Surface low is proggd to move from ND/SD border to near Lake
Superior. This will set up a southerly wind regime. The northern
CWA gets brushed with DCVA and the better frontal forcing holds
off to our west. Potent 850 LLJ traverses largely to our northwest
and north in conjunction with the low though core of strongest
winds and associated speed/moisture convergence is proggd to stay
to nor north. The models are basically split on whether to bring
precip into the CWA prior to 00z. The GEM and NAm are the drier
solutions while the GFS and ECMWF are more aggressive on bringing
some shra into the cwa. Will have chances spreading in during the
afternoon but there is some consensus that the southeast stays dry
for most if not all of the day. Even the wetter GFS shows a min
in the southeast corner. With the southerly winds the 925 temps
will be in the teens celsius so highs well into the 60s or low 70s
can be expected.
Tuesday night through Thursday...Forecast confidence medium.
Weak low pressure will move across the Lake Superior region Tue nt
with a trailing cold front to pass across srn WI. The frontal lift
is weak with a lack of upper support so only chances of showers
and slight chances of a tstorm.
Another weak low pressure area will then track from the cNortheast wind
regime keeping some elevated waves though speeds and wave heights
are coming in below criteria for small craft. Fog has improved as
well. Looking for a windier pattern to set up towards mid week
with low pressure approaching the area. entral Great Plains
through far srn WI or nrn IL, and onto Lower MI for Wed-Thu. The
nose of a strong LLJ will induce a well organized area of warm,
moist advection and frontogenesis while being supported aloft by a
weak vorticity maximum and the left front quad of an upper jet.
Showers and sct tstorms will begin Wed aft and continue into Wed
nt. Another inch of rain is expected with possibly more toward
central WI where lift is maximized from the aforementioned lifting
mechanisms. Rivers are experiencing above normal flows so would
expect several rivers to reach minor flood stage later in the
week. Lingering showers or drizzle will probably linger on Thu
along with cold advection and cool temps.
LONG TERM...Friday through Monday...Forecast confidence medium.
Srn WI will be on the srn periphery of a sfc high for Fri. A low
pressure area and upper wave will then move from the Lower MS
River Valley through the Ohio River Valley for the weekend. There
are only small chances for rain Sat nt-Sun AM as the system may
clip the area. Srn WI will once again be over the srn portion of a
high pressure area for Mon. Temps will be slightly below normal
during this period.
AVIATION(18Z TAFS)...88-d radar animation shows lake enhanced
frontal boundary pushing steadily west through srn WI. Winds
shift from wnw to ene as the front passes. Post frontal
stratus/fog appears to have dwindled in coverage near the lake but
plenty of higher based CU around as well. Next system approaches
on Tuesday but looks like most of TAF sites stay dry through 18z.
MARINE...Northeast wind .UPDATE...
&®ime keeping some elevated waves though
speeds and wave heights are coming in below criteria for small
craft. Fog has improved as well. Looking for a windier pattern to
set up towards mid week with low pressure approaching the area.
Tuesday Night through Monday...Gehring