FXUS63 KMKX 172050
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
250 PM CST Sat Nov 17 2018
Tonight and Sunday...Forecast Confidence is High.
Cloud cover is our main concern for the overnight hours. We are
expecting skies to clear toward central WI, so that area will
radiate out and temps should drop into the lower to mid teens.
Elsewhere, low clouds will be slower to clear. 1000-850mb winds
will be out of the northeast over far southeast WI through the
evening hours. That component off the lake will keep those low
clouds hanging around longest in that area. High clouds streaming
across far southern WI will also play a factor in our clearing
and the resultant temps. Min temps should only get into the lower
20s in southeast WI.
Sunday will be sunny with light westerly winds as high pressure
slides into the Central Plains. High temps will be similar to
today's, in the lower to mid 30s.
Monday and Monday night - Confidence...Medium
Broad mid level trough will be swinging through western Great Lakes
with embedded vorticity maxima. Surface/850 fronts will aid in lower
level forcing as well. A very light precipitation event here. The
ECMWF is dry in southern WI for the entire period while the GFS/NAM
show some minor qpf in the afternoon/evening. Thicknesses/850 temps
overall support this would be snow showers though boundary level may
warm sufficiently for some rain mixed in for a time as well. With
the passage of the front a cold northerly flow takes hold with the
likelihood of offshore lake effect snow showers. Trajectories will
be key on whether any of these manage to brush our eastern areas.
Tuesday and Tuesday night - Confidence...Medium
Warm air advection gets underway with lingering influence of low
level thermal trough getting shunted to the east. Another system
will be off to our northwest throughout the day and then head into
southern WI for the evening. Consensus of model solutions suggest
any light qpf with this system would affect mainly our northeast cwa
in the form of some snow showers.
Wednesday through Thursday night - Confidence...Medium
Surface high builds in Wednesday with waa set to arrive for Thanksgiving
Day and continue right into Friday. So mild temps are on the way.
Southwest winds and a broad low level anticyclonic curvature will
keep things on the dry side.
Friday and Saturday - Confidence...Medium
The next decent chance of some precipitation arrives this period as
mid level flow shifts southwest and energy starts to approach from
upstream trough. The ECMWF is the slowest and would keep Friday on
the dry side while the GEM and GFS bring rain into the area before
the day is out. Best model consensus for rain would be on Friday
night, though the ECMWF is still quite slow on bringing precip in.
Given the slower nature of the ECMWF and back edge of quicker
GFS/GEM, will hang on to some rain chances for Saturday. No real big
push of cold air in the wake of this system.
.AVIATION(21Z TAFS)...Ceilings are still hovering between 2000 and
4000 ft this afternoon, although there are lower ceilings around 1500
ft near the IL border and south. Lower clouds should linger in southeast
WI due to a northeast component to the wind off the lake through late
evening. Elsewhere, clouds will clear from north to south, although
high clouds streaming over the area will likely delay the full
clearing. Expect quiet weather and sunny skies on Sunday.
Nearshore... Northwest winds may reach small craft advisory
criteria Tuesday night. Southerly winds may reach that level
Thursday night through Friday.
Open Lake... A weak clipper crossing Ontario will bring gusty
westerly winds up to 25 or 30 kt over the north half of Lake
Michigan on Sunday. The next breezy period will be Tuesday night
with northwesterly winds in the wake of another clipper. Southerly
wind gusts could approach gale force toward the north half
Thursday night through Friday.
Tonight/Sunday and Aviation/Marine...Cronce
Sunday Night through Saturday...Collar
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