Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 282012
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
312 PM CDT FRI OCT 28 2016
.TONIGHT - Confidence...Medium
Strong west/east jet stream riding the far northern US with no real
siggy vort maxes noted. A surface low will shift east of Lake
Superior by morning and drag a trailing frontal boundary into srn
WI. A very mild airmass will be in place tonight with potential for
mild temps to be maintained by pure thermal advection with a
subsequent non-diurnally induced max temp.
.SATURDAY - Confidence...Medium
Lingering influence of low level thermal ridge axis will be in place
across the area during the morning. A gentle collapse in the 925/850
temps is expected as low level wind flow turns more north behind the
front. 500 millibar flow remains strong but any vorts of concern
holds off until after 00z. Column is overall quite dry. The NAM is
showing considerably more saturation in the boundary with a
pronounced inversion. Will keep any rain chances confined to the far
northwest CWA where shortwave gets a little closer and rrq
divergence associated with 200-300 millibar jet. Would expect to see
some cooling take shape in the afternoon as the winds eventually
turn more ne in the post frontal environment.
.SATURDAY night and Sunday...Forecast Confidence Is High.
A weak shortwave moves across Wisconsin late Saturday night and
early Sunday morning with a weak upper ridge building into the
Upper Mississippi Valley late Sunday afternoon. There is a band of
moderate upper level divergence and 700 mb upward motion through
much of the night until the mid level trough axis exits.
700 mb layers dry behind the departing trough axis. The low
levels dry a little later Sunday morning and especially Sunday
The GFS and ECMWF produce some rain with the mid level trough
axis and baroclinic zone Saturday night. High pressure then
builds into the Upper Mississippi Valley and Great lakes Sunday.
.Sunday Night and Monday...Forecast Confidence Is Medium.
A rather strong mid/upper level shortwave moves into the northern
Rockies, but flattens into a low amplitude shortwave over the
Northern Plains and Upper Mississippi Valley Monday. The ECMWF has
a stronger shortwave.
This forms a low across western South Dakota that reaches
northern Minnesota by early Monday evening. A brisk south wind
will briefly bring warm air back into Southern Wisconsin Monday.
Both the GFS and ECMWF keep southern Wisconsin dry.
.Monday Night and Tuesday...Forecast Confidence Is Medium.
The shortwave moves across the Lake Superior area Monday night and
into southeast Canada Tuesday, with a west/southwest upper flow
across southern Wisconsin.
A cold front moves across Monday night. The models do not produce
any showers with the cold front. A weak high then moves into
.Tuesday Night and Wednesday...Forecast Confidence Is Medium.
A west/southwest upper flow extends across Wisconsin Tuesday
night with a shortwave moving toward the Upper Mississippi valley
The Surface high exits Wisconsin Tuesday evening with both the
GFS and ECMWF bringing light rain into Southern Wisconsin later
Tuesday night and Wednesday morning ahead of a warm front.
.Wednesday night and Thursday...Forecast Confidence is Medium.
The ECMWF has trended toward the GFS building an upper ridge into
The GFS builds a surface high across Wisconsin with the ECMWF
moving the high off a little quicker.
.Thursday Night and Friday...Forecast Confidence is Medium.
The 12Z Ecwmf brings a strong shortwave just north of the DakotaThursday,
while the GFS has zonal flow north of the Upper ridge. Either way
both models still have riding across Wisconsin.
Strong west/east 500-300 millibar flow carrying any vorts to our
north this period. Potent waa regime continues into tonight ahead
of surface/850 boundary. Surface boundary proggd to sag through
srn WI later tonight into early Saturday with 850 boundary lagging
a bit. Main aviation concern tonight will be low level wind shear
as strong 850 jet translates across srn WI. Progs suggest some
more stratus potential along and ahead of the surface front.
An area of low pressure tracking across lake Superior
tonight, will bring a tight pressure gradient to the nearshore
waters, resulting in strong south winds. Will retain Gale Warning
issued this morning for the northern zone especially since core of
strongest 850 millibar winds yet to arrive. The small craft advisory
remains in effect elsewhere, with the Gale warning north of Port
Washington after 4 pm. Highest waves will be north of Port
Another low pressure system moving through the area will bring small
craft advisory conditions for Monday and Monday night due to strong
LM...SMALL CRAFT ADVISORY until 7 AM CDT Saturday for LMZ644>646.
SMALL CRAFT ADVISORY until 4 PM CDT this afternoon for LMZ643.
GALE WARNING from 4 PM this afternoon to 1 AM CDT Saturday for
TONIGHT/Saturday AND AVIATION/MARINE...Collar
Saturday NIGHT THROUGH Friday...Hentz