Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 211443
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
943 AM CDT Tue Mar 21 2017
An area of widespread mid clouds and scattered showers has
developed across much of Iowa in association with the right
entrance region of a jet streak to our northeast and a weak mid
level short wave, which is pushing southeast through Iowa. Those
clouds are currently moving into southern Wisconsin, and current
trends have them pushing across more of the area and lingering
longer than was indicated in the previous forecast. Accordingly,
high temperatures in the southeast may need to be adjusted
Meanwhile, cold front is still on track to push though the area in
the early afternoon, dropping temperatures and swinging winds
around to the northeast. Those onshore winds and cold temperatures
aloft may be enough to support some lake effect snow showers this
Cold front still on track to push through the area this afternoon.
It appears that small craft criteria may be reached a few hours
after the SCA goes into effect (21z), especially in the north,
but will hang onto the 21z start time to account for the sudden
wind shift with the frontal passage.
.PREV DISCUSSION... (Issued 639 AM CDT Tue Mar 21 2017)
AVIATION(12Z TAFS)...Nly winds today and tnt due to the passage
of a cold front. MVFR Cigs will develop around sunset over ern WI
due to scattered lake effect snow showers developing over ern WI.
LES will continue through the evening with some drying after
PREV DISCUSSION... (Issued 333 AM CDT Tue Mar 21 2017)
Today and Tonight...Forecast confidence medium.
The cold front currently entering nw WI will move across srn WI from
late morning into the early afternoon. Broken high clouds will occur
at times over srn WI as a vorticity maximum and mid level
frontogenesis passes from the Great Plains into IL. Broken
stratocumulus may develop in the afternoon over east central WI as
low level instability develops with the stronger cold advection
aloft. High temps will range from the lower to middle 40s. For
tonight, a nnely onshore flow and lake to 850 mb temp differences of
13-15C will bring chances of snow showers to ern WI mainly in the
evening. Forecast soundings do dry out more after midnight as the
nnely winds advect drier air into the region.
WEDNESDAY... Forecast confidence is medium.
Wednesday should be a cold and clear day, with the exception of some
lake effect clouds due to easterly winds. Light snow showers and
flurries are not out of the question for the morning hours. Highs
are expected in the 30s near the lakeshore and around 40 well inland.
THURSDAY THROUGH SATURDAY... Forecast confidence is medium.
Southerly winds with return flow around the high will usher moisture
back into southern WI by Thu evening. Warm frontal rain showers are
expected to arrive late Thu afternoon or evening. Models show weak
elevated instability in the vicinity of the warm front, so kept
small thunder mention Thu night.
Southern WI will get into the warm sector of this occluding low
pressure system. The low will be back over the Plains on Friday
while the occluded front advances into the Midwest. The warm front
is expected to remain fairly stationary across central/southern WI
Fri afternoon through Saturday as the low slowly tracks through
Southern WI will have a prolonged period of rain late this week.
Models are showing up to an inch of rain is possible in our northern
SUNDAY THROUGH TUESDAY... Forecast confidence is medium.
It looks like a very active weather pattern for next week with a
series of shortwave troughs tracking into the Midwest from the
Plains. Temperatures appear warm enough for all rain.
Patchy MVFR fog around sunrise. Otherwise VFR into Tuesday
afternoon. Mainly mid/upper level clouds until early Tuesday
evening when Lake enhanced MVFR clouds/flurries possible.
A Small Craft Advisory goes into effect at 4 PM CDT for brisk
northerly winds and high waves in the wake of a cold front. The
winds and waves will gradually subside through Wed AM. The Advisory
will expire at 10 AM CDT on Wed.
LM...Small Craft Advisory from 4 PM this afternoon to 10 AM CDT
Wednesday for LMZ643>646.
Today/Tonight and Aviation/Marine...Gehring
Wednesday THROUGH Monday...Cronce