Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 151010
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
510 AM CDT SAT OCT 15 2016
.TODAY AND TONIGHT...Forecast Confidence Is Medium.
Stratus clouds are rapidly approaching from the south but also
from the west via moisture transport on a swly 45kt low level jet.
Breezy sly winds and moisture advection will continue today with
the low to mid level thermal ridge shifting south across the
region. Some breaks in the cloud cover are possible, more so over
se WI. Upper 60s temps look reasonable for high temps today.
For tonight, the cold front will gradually shift esewd into srn
WI. A vorticity maximum will also approach by late evening and
move across srn WI during the overnight. Continual moisture
transport will boost PWs to 1.5 inches by midnight. Showers and
scattered tstorms will begin to develop early in the evening after
the low to mid level thermal ridge shifts south and the shortwave
trough approaches. Forecast soundings depict tall, skinny MUCAPE
between 500 to 1000 joules. Precipitation coverage will expand by
late evening and the overnight as the shortwave trough coincides
with the highest PW airmass.
.SUNDAY THROUGH MONDAY NIGHT...Forecast Confidence Is Medium.
Models are in general agreement with keeping some light QPF across
the southeast half of the forecast area Sunday morning. A modest
500 mb vorticity maximum pushes through the area during this
time, along with weak low level frontogenesis response. Kept in
lower end PoPs for the morning, lingering in the far southeast in
the afternoon as frontogenesis response lingers.
Area forecast soundings suggest a cap building in the 850 mb to
700 mb layer, which may lead to a drier forecast. Mostly cloudy
skies should limit highs to the upper 60s in the east, to the
lower 70s west, despite warm air advection developing.
Chances for showers and thunderstorms linger Sunday night into
Monday evening, mainly in the northern portions of the area.
Models are taking a warm front northeast across the area Sunday
night and to the northeast Monday. A cold front then approaches
the area from the northwest Monday night.
The low level jet seems to focus to the north of the area Sunday
night, with another focusing northeast of the area Monday into
Monday night. The best 500 mb differential cyclonic vorticity
advection seems to remain north of the area as well.
Area forecast soundings suggest the cap lingering Sunday night
into Monday across the area, as warm air advection pushes in.
Thus, it could be dry for this period as well, especially in
southern portions of the area. There is not a lot of upward
vertical motion with the cold front Monday night, with some
models dry over the area. Uncertainty exists with PoPs for Sunday
night into Monday night at this time.
Warm temperatures are expected Sunday night into Monday night, on
breezy south to southwest winds. Mainly mid 60s are forecast
Sunday night, with highs Monday into the mid to upper 70s. Could
see highs hit 80 in the south, where some sun may peek through the
clouds. Record highs and high minimums for Monday may be possible
at Milwaukee and Madison, depending on if some sunshine occurs.
.TUESDAY THROUGH FRIDAY...Forecast Confidence Is Medium.
The ECMWF and GFS appear to be trending toward keeping a majority
of the QPF with the developing low and cold front southeast of the
area for Tuesday into Wednesday. The GFS does try to bring in QPF
later in the week, as it has the surface low further west with a
more amplified and closed 500 mb low over the central part of the
The ECMWF is more of an open wave at 500 mb later in the week,
and further to the east with the trough and surface low. Given the
differences here, will leave the consensus blended PoPs and
temperatures for now. After another warm day Tuesday with lower
70s forecast, temperatures trend downward closer to seasonal
normals for later in the week. There is uncertainty here with
trends this far out.
Moisture transport into srn WI will result in widespread stratus
today and tonight although some breaks in the cloud cover is
possible this afternoon. Cigs will range from 500 to 1500 feet this
morning lifting to 1-2.5 kft this afternoon and early evening.
Showers and scattered tstorms will occur tonight. The moist boundary
layer and lighter winds later at night will result in areas of fog.
There may be brief areas of 3-5sm br this morning but it will become
more widespread late this evening. Vsbys may then drop to 1/2 to 1
mile around KMSN and to the north and west of there for early Sun
A Small Craft Advisory is in effect until 09z Sun. Breezy sly
winds and high waves will prevail today with the approach of a
cold front from the west. The highest waves of 4-6 feet will be
found mainly north of Port Washington. The winds and waves will
gradually subside through tonight.
LM...SMALL CRAFT ADVISORY until 4 AM CDT Sunday for LMZ643>646.
TODAY/TONIGHT AND AVIATION/MARINE...Gehring
Sunday THROUGH Friday...Wood