Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 191428 AAA
Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
928 AM CDT THU MAY 19 2016
Sunny skies this morning will give way to diurnal cumulus in the late
morning and afternoon. Based on latest model soundings, forecast
sky cover may need to be bumped up away for this afternoon away
from Lake Michigan. Temperatures should be right around normal
VFR conditions will persist through Friday under high pressure.
Should see more rounds of diurnal cumulus today and Friday.
High pressure centered over the great lakes will bring light winds
and low waves through the weekend. Lake breeze with southeast winds
during the day and mainly south southwest winds at night.
.PREV DISCUSSION... /Issued 318 AM CDT THU MAY 19 2016/
TODAY AND TONIGHT...FORECAST CONFIDENCE HIGH
Mid-level ridging over Wisconsin breaks down as a short wave drops
from southern Manitoba into northern Minnesota by 12Z Friday.
Core of broad high pressure from the surface up to 850 mb extending
across the state will slowly shift east to the eastern Great Lakes
by 12Z Friday, allowing some weak warm air advection with developing
southerly flow that raises 925 mb temperatures 2C to 3C higher than
Wednesday by late this afternoon.
Have adjusted highs upward a few degrees from yesterday`s
values to account for this. Forecast soundings again indicate
shallow scattered to broken diurnal cumulus developing this
afternoon with the higher coverage in the western CWA away from the
stable lake air pushing inland during the afternoon.
With the core of the high shifting east, enough wind for only a
moderate nocturnal inversion that along with the rising 925 mb
temperatures will help hold lows in the lower to middle 40s.
FRIDAY THROUGH SUNDAY - Confidence...High
Very quiet wx regime continues with surface/850 high dominating with
dry air/subsidence. An onshore flow is expected each day due to
either diurnally induced lake breeze formation or overall synoptic
scale flow favoring the wind off the lake. A mid level wave rides se
down eastern periphery of plains ridge later saturday night into
sunday morning. Due to dry airmass and influence of lower level
subsidence with the surface/850 ridging, will not introduce any pops
with this mid level feature. By Sunday we will be positioned in a
favorable position within an elongated mid level ridge axis between
approaching plains trough and east coast trough. The low level flow
is proggd to become more southerly on the GFS and GEM however the
GEM shows less progression of the low level ridge axis and a
somewhat cooler regime.
MONDAY - Confidence...Medium to High
The mid level ridge axis shifts to our east and the area will see an
increasingly southwest flow at 500 millibars. In addition the low
level anticyclone even on the GEM shifts east and allows for a
southerly 925/850 flow from all the models to lead to further
warming across srn wi. Earlier model runs suggested some afternoon
influence of approaching frontal boundary into sw wi could result in
shra/tsra chances arriving into wrn portions of the cwa. However
both the 00z GFS and 00z ECMWF keep the focus to our west or
northwest. For now will leave the slgt chc superblend pops in place
for the western cwa during the afternoon. However should future
model runs keep the slower trend in place these pops could be
TUESDAY AND WEDNESDAY - Confidence...Medium
Surface boundary is proggd to be a focus for shra/tsra along with
increasing mid level dynamics from shortwave activity and favorable
upper jet streak circulations. So for now the superblend pops are
reasonable showing the uptick in precip potential.
AVIATION/12Z TAFS/...VFR conditions continue through the forecast
period. Diurnal cumulus, with bases in the 6k ft to 8k ft range
will develop again late this morning, mainly away from Lake
Michigan, dissipating late this afternoon into early evening.
Light southwest winds will turn southeast in the eastern forecast
area by early afternoon with a combination of gradient wind and
lake breeze while the west will see south winds during the day
backing southeast tonight.
MARINE...High pressure will bring light winds and low waves through
TODAY/TONIGHT AND AVIATION/MARINE...REM
Friday THROUGH Wednesday...Collar