FXUS63 KMKX 242254
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
554 PM CDT Thu May 24 2018
Quiet and very mild tonight. No changes to the short term forecast
Expect VFR conditions through the TAF period. Toward the end of
the TAF period (00z Saturday), we expect a line of showers and
thunderstorms, initially developing over northern and central
Wisconsin, to push south through the evening. A few of these
storms could be severe with 1 inch hail and winds to 60 mph. They
would mainly be west of KMKE/KUES/KENW.
.PREV DISCUSSION... (Issued 343 PM CDT Thu May 24 2018)
Tonight through Saturday Morning...Forecast Confidence is High...
The primary concern in this period is the potential for
thunderstorms tomorrow afternoon and evening. Southerly winds at
the surface will usher in more warm and moist air, pushing
Friday's high temperatures into the upper 80s and MLCAPE values
into the 1000-1500 j/kg range.
Meanwhile, an upper level shortwave will swing through the region
Friday afternoon/evening, providing a source of synoptic scale
lift for storms. Storms will likely initiate in western WI/
southeastern MN in the afternoon before pushing into southern
Wisconsin in the late afternoon and evening.
Given 0-6 km bulk shear magnitudes in the 20-30 kt range, impacts
from the storms will likely be limited to scattered heavy rain,
small hail, and gusty winds. However, with the instability levels
mentioned above, steep lapse rates, and some dry air evident in
the soundings, there is a marginal risk for storms putting down
hail up to 1" and winds up to 60 mph.
Saturday and Sunday...Forecast Confidence is High...
The northern stream shortwave Over Michigan moves across the
Eastern Great Lakes. A general west/northwest flow pattern aloft
along the U.S. canadian border. Overall, flow is weak and warm and
humid conditions will continue. Forecast soundings show moderate
CAPE values. However little if any forcing. As a result model
runs are trending drier for Saturday and Sunday but a brief
thunderstorm is not out of the question.
With the summer-like upper pattern, very warm temperatures are
expected, with a lake breeze developing close to lake Michigan.
Memorial Day through Thursday...Forecast Confidence is Medium...
A weak upper ridge builds into Wisconsin Monday, before an
upstream shortwave moves in late Tuesday and Wednesday.
Surface High pressure brings quiet weather on Memorial Day. This
will cause winds to become more easterly, but still light.
Temperatures may start to cool Monday near Lake Michigan with the
onset of the easterly flow.
Slightly cooler, but still warm, temperatures are expected
starting Tuesday. Precipitation chances increase mid week, with
still mild temperatures.
After a quiet night, concern then turns to the potential for
storms tomorrow afternoon and evening. The ingredients appear to
be in place for scattered storms, and the meso models are picking
up on this. Storms appear to be more likely in the west, and there
is a marginal risk for some of these storms to put down hail up
to 1" and winds up to 60 mph.
Conditions will be calm until Friday when southwest winds pick up
to around 15 kts, pushing wave heights to around 2-3 feet in the
afternoon. Thunderstorms are also possible on Friday afternoon.
This weekend, temperatures will push into the upper 80s and dew
points will reach well into the 60s over land. As this air advects
over to cool lake, dense fog remains a possibility.
Tonight/Friday and Aviation/Marine...BSH
Friday Night through Thursday...Hentz
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