Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 301940
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
240 PM CDT Thu Mar 30 2017
.TONIGHT - Confidence...Medium
Large storm system continues to churn eastward through the middle of
the country. Meso models show a diminishing trend in precip coverage
as the night wears on. In fact already seeing a dropoff in precip
coverage from sw WI into ern IA. Renewed surge across wc IL expected
to remain largely south of WI and trend east but will keep some pops
going for a time this evening to account for any additional rain
that may form ahead of the mid level trough axis. Very little in the
way of diurnal dropoff expected with the cloud cover and winds.
.FRIDAY - Confidence...Medium
500 millibar low will trend into the Ohio Valley with more of an
anticyclonic mid level flow taking hold. Models still hold onto some
light QPF in the morning so will have some POPS in place to account
for this. LLVL RH progs from the NAM and GFS keep things cloudy
while the ECMWF hints sunshine evolving later in the northern CWA.
So best shot at any clearing would appear to be in the north late.
FRIDAY NIGHT and SATURDAY... Forecast confidence is high.
An mid/upper ridge builds into southern Wisconsin. Upper level
divergence begins to increase. 700 mb RH is low.
Drier air with surface high pressure builds into the region on
Saturday and will help to scour out the clouds for a short period
of time. Light winds and some sunshine will allow highs to return
to the 50s inland from the lake.
Saturday night through Monday... Forecast confidence is medium.
Another upper low will track from the southern Plains through the
mid to lower Mississippi River Valley over the weekend, with a
northern stream shortwave pushing across southern Wisconsin.
Southern WI has a decent chance for light rain Sunday afternoon into
Sunday night, and perhaps Monday morning, before the surface
TUESDAY THROUGH THURSDAY... Forecast confidence is medium.
A ridge of high pressure will move across southern Wisconsin
Monday night and over the Great Lakes Tuesday.
A strong trough will move across the Mid Mississippi Valley
Wednesday. Precipitation could spread into southern Wisconsin as
early as Tue night with the faster GFS. Thickness cools and the
GFS is trending colder, with precipitation possibly changing to
snow north and west areas Wednesday.
The 12Z ECMWF is trending more toward the faster GFS, but is a
little farther north with the surface track, resulting in mainly
rain over much of the forecast area.
With low pressure south of WI we continue on the rainy, cloudy
and cool north side of this system. Already starting to see some
decrease in rain coverage across sw WI into ern IL. Plenty of IFR
and some LIFR ceilings with some IFR vsbys closer to Lake
Michigan. Progs take the low to the east and keep us reinforced in
this regime this period. So expect cigs/vsbys to be fairly
consistent. As low tracks more to the east winds starting to turn
more to the northeast and eventually north for Friday. Rain
coverage decreases tonight into Friday morning with some
improvement in ceilings as well though enough LLVL RH lingers to
keep the cloud cover locked in place with a chilly NNE wind.
No Change to the Small Craft Advisory. A tight pressure
gradient persists around low pressure centered in Missouri. The NE
wind regime generating gusts to 20 knots plus and expect some gusts
to possibly reach the 25 to 30 knot range at times. Winds will start
turning more to N tonight into Friday and remain gusty with high
waves being generated.
LM...Small Craft Advisory until 4 AM CDT Saturday for LMZ643>646.
Tonight/Friday and Aviation/Marine...Collar
Friday Night through Thursday...Hentz