Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 261509 AAA
Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
1009 AM CDT WED OCT 26 2016
The back edge of the higher returns on radar is steadily tracking
across southern WI this morning. While this is the end of
heavy/moderate rain, expect light rain showers and/or drizzle to
persist through the afternoon across south central WI and probably
the evening hours in southeast WI.
The strong synoptic forcing, leading shortwave trough, right
entrance region of the upper jet, and deep moisture will continue
shifting east today. The main upper trough will lag behind and not
exit WI until after midnight tonight. Because of the cyclonic flow
and lingering low level moisture, drizzle and light rain are
expected through the afternoon/evening.
Widespread rain will lower cigs from MVFR to IFR behind this main
band of rain today as surface low pressure tracks from eastern Iowa
this morning, to northern Indiana by late this evening. The rain
will diminish from west to east this afternoon with light rain and
drizzle continuing into the evening. All the rain/drizzle should
end by sunrise Thursday. But, cigs will likely remain IFR through
about 12z Thursday, then gradually lift thereafter.
Look for strong southeast winds to persist through the afternoon,
especially for the KMKE/KUES/KENW TAF sites. A few gusts will be
pushing 30kts at times. Winds will diminish quickly this evening.
Gale force winds likely be highest into early afternoon with gale
force east winds continuing into the early evening. This is in
response to an intense low pressure system tracking across northern
Illinois, to northern Indiana by later this evening. The winds will
diminish overnight with lighter northerly winds expected on
Low pressure tracking by to the north of the area on Friday will
generate gusty southerly winds that will likely result in small
craft advisory conditions for Friday into Friday night.
.PREV DISCUSSION... /Issued 315 AM CDT WED OCT 26 2016/
TODAY AND TONIGHT...Forecast Confidence Is High.
A compact surface low pressure system will track from central
Iowa this morning to northern Indiana by late this evening. This
system has a lot going for it. There`s a potent mid level short
wave, a sharp h8 baroclinic zone with the warm front laying out
across southern WI, and a moderately strong low level jet
supporting deep isentropic ascent within a moisture rich axis.
PW`s are at an inch or better.
The guidance still supports the heaviest rain area over the nrn
half of the forecast area today, lowest along the WI/IL line. No
real change to the going forecast. Rivers will rise with this
rain, with a few sites expected to reach bankfull levels, mainly
north of Milwaukee and Madison. Urban areas could see some
localized street flooding, due to clogged drainage systems from
all the fallen leaves.
It will be a raw day, with highs in the mid 40s and a strong
southeast wind kicking in, especially over eastern WI and along
the Lake Michigan shoreline. We should see a few gusts pushing
30-35 mph. The rain will diminish from west to east this
afternoon, becoming light and drizzly for a time this evening,
before ending after midnight.
THURSDAY THROUGH FRIDAY NIGHT...Forecast Confidence Is Medium.
Models are in decent agreement with high pressure pushing
eastward, to the south of the area, Thursday into Thursday
evening. This should bring dry conditions to the area. However,
mid level clouds should linger during this time. This should keep
highs Thursday in the upper 40s to around 50 in the northern
counties, to lower 50s in the southern counties.
Warm air advection then develops across the region later Thursday
night into Friday, as low pressure passes eastward across the
U.S./Canadian border into Lake Superior. A tight pressure gradient
develops Friday in the area, lingering into Friday night. This
should bring gusty south to southwest winds with warmer
Some middle to high clouds may linger, which will affect
temperatures. For now, went with highs in the 60s across the area,
highest in the south and west. It may get warmer if clouds are not
as plentiful as currently forecast.
Cold front then passes eastward through the area Friday night. NAM
is the only model that is producing any QPF across the area. It
seems overdone with elevated CAPE, as GFS soundings are not
showing nearly as much of it. Kept small PoPs for showers in the
far northeast areas Friday evening, but this may need removal if
dry look of most of the models continues.
SATURDAY THROUGH TUESDAY...Forecast Confidence Is Medium.
ECMWF/GFS are in decent agreement with features for Saturday into
Tuesday. They have some cold air advection over the area Saturday,
as high pressure builds into the region from the northwest. There
is a band of QPF that spreads east across the area Saturday
afternoon and evening, with some frontogenesis response and
differential cyclonic vorticity advection with a modest 500 mb
ECMWF is more widespread than the GFS with the areal coverage of
the QPF. Kept PoPs going for Saturday afternoon and especially
Saturday evening. Clouds over the area may limit highs a bit, with
lower to mid 60s.
Temperatures cool Saturday night into Sunday, as the high moves
through. Warm air advection then kicks in once again for Monday,
before a cold front moves east through the region Monday night or
Tuesday. There is some timing differences this far out with the
frontal passage, with the ECMWF slower and the GFS faster.
Warm temperatures should return Monday, with mid to upper 60s at
least. It could get warmer than that. Kept lower end PoPs for
Monday night in northern portions of the area for now, with a
passing 500 mb vorticity maximum in northern and central
Widespread rain will lower cigs from MVFR to IFR today, as
surface low pressure tracks from central Iowa this morning, to
northern Indiana by late this evening. Look for strong southeast
winds to develop this morning, especially for the KMKE/KUES/KENW
TAF sites. A few gusts will be pushing 30kts at times.
The rain will diminish from west to east this afternoon, with
light rain and drizzle continuing into the evening. All the
rain/drizzle should end by sunrise Thursday. But, cigs will likely
remain IFR through about 12z Thursday, then gradually lift
thereafter. Winds will diminish quickly this evening.
Look for gale force southeast winds developing this morning, and
continuing into the early evening. This is in response to an
intense low pressure system tracking from central Iowa this
morning, to northern Indiana by later this evening. The winds will
diminish overnight, with lighter northerly winds expected on
Low pressure tracking by to the north of the area on Friday will
generate gusty southerly winds, that will likely result in small
craft advisory conditions, for Friday into Friday night.
LM...GALE WARNING until 10 PM CDT this evening for LMZ643>646.
TODAY/TONIGHT AND AVIATION/MARINE...Davis
Thursday THROUGH Tuesday...Wood