Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 181921
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
221 PM CDT WED MAY 18 2016
.TONIGHT AND THURSDAY...FORECAST CONFIDENCE...HIGH
High pressure will bring mostly clear skies overnight, with another
round of late morning and afternoon cumulus likely Thursday, mainly
away from Lake Michigan.
A dry airmass and good radiational cooling conditions will allow
temps to fall to a few degrees below normal values tonight.
Temperatures Thursday will be right near normal.
.THURSDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE IS HIGH.
This will be a quiet period for southern Wisconsin as surface high
pressure brings us dry conditions and gradually warming temperatures.
Meanwhile, on the synoptic scale, a meridional flow pattern will
evolve aloft, featuring Great Plains ridging and troughing digging
from the central Great Lakes into the central/southern Appalachians.
A meandering upper low will also pinwheel about the west coast and
Great Basin regions. This pattern will keep the majority of the
shortwave energy well away from us, with only a sheared ribbon of
vorticity passing through southern Wisconsin Friday evening into
Saturday. The 18.06Z and 18.12Z GFS solutions paint some splotchy
and very light QPF across the area with this wave on Friday and
Saturday afternoon, but this seems overdone. Forecast soundings do
suggest scattered to broken diurnal cumulus development inland
with a moist layer around 5-6 kft on Friday. 925 mb temperatures
support surface highs climbing into the 70s inland, with a lake
breeze keeping readings a bit cooler along and just inland from
the lake. Lows will drop into the mid to upper 40s area-wide, so
thankfully no more frost or near freezing temperatures to contend
.SUNDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE IS MEDIUM.
Amplified ridging aloft on Sunday will support surface ridging
holding court over the western Great Lakes region. Meanwhile,
moisture transport increases across the Great Plains ahead of
increasingly progressive troughing across the west. Expecting
another warm day in southern Wisconsin with drying soils
contributing to high temperatures well into the 70s inland. Pressure
gradient still appears weak enough for an onshore component keeping
cooler readings along the Lakeshore however.
The surface high is shunted to the east on Monday as the leading
shortwave associated with the upper trough approaches from the
west. Robust moisture transport on southerly low-level winds
should allow precipitable water values to approach one inch by
Monday afternoon. Shower and thunderstorm chances will increase
from west to east from Monday night into Tuesday as cyclonic
vorticity advection and jet-level divergence contribute to
enhanced vertical ascent ahead of a slowly moving cold front.
These chances will continue into Wednesday, as the front stalls
across the region. Strong storms may be possible at times through
this period. Temperatures will remain on the mild side.
Diurnal cumulus will dissipate late this afternoon into early
evening. Should see another round of cumulus at a similar height on
Thursday, mainly away from Lake Michigan.
High pressure will bring light winds and low waves through the
TONIGHT/Thursday AND AVIATION/MARINE...DDV
Thursday NIGHT THROUGH Wednesday...SPM