Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Milwaukee/Sullivan WI
300 am CDT sun Jul 31 2016
Today and tonight...forecast confidence is medium.
A combination of a persistent moist easterly flow off Lake Michigan
and instability over the lake will result in lower clouds across the
southeast this morning. These should gradually mix out during the
morning as they compete with some lower relative humidity values inland. Some of
the high res models try to fire off some showers or a thunderstorm
along the lake breeze this afternoon, but this seems ambitious given
the lack of deep moisture. Think chances are below 15 percent, so
will leave it out for today. Overall, a rather nice day on tap
across the area with normal temps and light winds expected.
High pressure continues the quiet trend into tonight with lows
dropping into the upper 50s to mid 60s. Enjoy as we will see much
warmer temps coming in later this week.
Monday - confidence...medium
surface high pressure will dominate for the most part. Mid level
ridging will be in control though a weak vort axis is proggd to
affect the western cwa in the afternoon. This will also be in a
region of increasing 850 millibar moisture advection. Will have some
small pops in the western cwa to account for some of these
features. 925 temps modify 20 to 23c during the afternoon so many
locales back into the low 80s.
Monday night and Tuesday - confidence...medium
progs continue to show mesoscale convective system potential for this period with increasing
850 moisture transport and a shortwave coming through at the mid
levels. The upper jet is pretty far north though models are still
showing some divergence signals across the area. Cwasp numbers by
no means ambitious. Swody2 has US in a marginal risk and that seems
reasonable. Models suggest after one round moves through overnight
into early Tuesday that the airmass will some potential to recover
for additional development. Will have to see how the earlier stuff
impacts things as we draw closer. Southwest 925/850 winds will be
pumping in a very warm and humid airmass with 925 temps rising
deeper into the 20s celsius and MOS dew points showing a return to
some 70f plus dew points.
Wednesday and Wednesday night - confidence...medium
this looks like a relative break in the precip as a weak bubble of
high pressure settles in. Not a big cool down with 925 temps still
20 to 25c. Mid level ridging also builds up across the area with the
better forcing off to the northwest in nrn/cntrl Minnesota.
Thursday and Thursday night - confidence...medium
mid level flow is proggd to flatten and bring a frontal boundary
through the area. Not a real strong vort but just the increasing
westerly mid/upper flow and some divergence. Still looking like
Thursday evening through the overnight is the best time frame as
surface/850 frontal boundaries move into srn WI. Expecting plenty of
heat ahead of this system. Like with yesterday's runs the European model (ecmwf) is
showing more warm sector qpf than the GFS so the GFS has maintained
a hot thermal ridge axis with 925 temps 27-30c.
Friday and Saturday - confidence...medium
some indications that some of this precip may linger into the
morning hours on Friday but otherwise it looks quiet this period. A
rather swift northwest 500 millibar flow with high pressure and a
somewhat drier airmass settling in.
Aviation/12z tafs/...pesky MVFR ceilings will stream in off Lake Michigan
this morning, but should lift to VFR by late morning, then scatter
out as the moisture mixes out during the day. We could see some MVFR
visibilities as well this morning, but that should burn off within an hour
or two after sunrise. Winds will be light, less than 10 knots.
Marine...look for light northeast winds and small waves through
tonight. Winds will remain light through much of the week ahead.
Today/tonight and aviation/marine...Davis
Monday through Saturday...collar