Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 250807
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
307 AM CDT TUE OCT 25 2016
.TODAY AND TONIGHT...Forecast confidence is medium.
A high pressure ridge centered over eastern Wisconsin at sunrise
will slide off to the east today as low pressure heads our way from
the Central Plains. The forcing from the warm air advection out
ahead of the low will reach our area later this afternoon, so look
for increasing clouds today. A few models try to generate some light
qpf over the western forecast area, but the dry air in the low
levels will likely keep it all virga initially. If any precip is
felt at ground level, it should just be the sprinkle variety. The
main surge of deeper moisture, isentropic lift/saturation and
differential vort advection arrives later this evening. Look for
the rain to gradually overspread the area, especially after
midnight. Soundings show no CAPE, so pulled the thunder mention
The pressure gradient tightens up, especially after 3am, so should
get a bit breezy/gusty from the southeast late tonight.
.WEDNESDAY AND WEDNESDAY NIGHT - Confidence...High
Continued strong consensus and consistency for a wet, cool and
windy day as low pressure moves through the area. Surface low
tracks through central IL so expect a gusty ese wind along with
the clouds and rain. Nudged temps down a bit along with a nudge up
in the wind speeds/gusts over the blended solution. Going with 100
pops for at least the morning hours but 100`s may end up working
all day in the east. Orientation of 850 jet max places srn WI
within left front quad for maximum lift/moisture advection through
at least midday. Noting some upper divergence with a right rear
quad of 200-300 millibar jet max. 500 millibar shortwave rides
through with a couple periods of DCVA aiding to the lift. The best
lift shifts east Wednesday night so kept shra chances in the
evening with sfc low and upper wave sliding into the Ohio valley.
.THURSDAY - Confidence...Medium
Surface/850 ridging gradually takes hold. Also noticing a trend
towards building 500 millibar heights as the mid level flow becomes
.FRIDAY - Confidence...Low to Medium
WAA regime sets up with 850 temps surging into the teens celsius.
Both the ECMWF and GFS develop some shra with the waa across mainly
the northern CWA. If this trend continues then we may be able to
scale back on some of the southern POPS we have going. So the POPS
for the south are low confidence at the moment, especially with 500
millibar energy well north. Temps will get a nice boost though the
waa cloud cover may temper the boost somewhat.
.SATURDAY - Confidence...Low
Models are now trending towards a warmer solution unlike last nights
00z run where some chilly 850 temps were noted. In fact the current
ECMWF shows 850 temps around 15c. Presently about a 10c spread
between the warm ECMWF and colder GFS. The ECMWF shows a surface low
in wc WI while the GFS sags a front into nrn IL with that cooler
post-frontal northerly flow. Given this disparity will not deviate
from Superblend. Also both the GFS and GEM show a strip of very
light post-frontal qpf that could result in some afternoon POPS
being needed Saturday afternoon. But some of this would linger into
Saturday evening when the ECMWF brings the trailing cold front with
the potential for some post-frontal precip with this solution as
.SUNDAY AND MONDAY - Confidence...Medium
Surface high dominates Sunday with broad mid level ridging taking
hold. The GFS is quicker with upstream trough and further north with
any waa qpf heading into Monday. At the moment we just have POPS in
the far north with this. Looks fine for now with moisture looking a
little meager per Bufkit so the overall quieter POP scenario not
too bad at this point.
.AVIATION/12Z TAFS/...VFR conditions are expected through the TAF
period, but conditions will be deteriorating rather quickly from
west to east after sunrise Wednesday morning. High pressure over
the area this morning will slide east as low pressure approaches.
East to southeast winds will increase rapidly later tonight,
especially for the southeast WI TAF sites. Look for mid level
clouds to increase rapidly this afternoon. Regional radars will
likely show some rain moving into areas west of KMSN this afternoon,
but it likely won`t be reaching the ground due to a very dry low
level airmass. Saturation will occur rapidly tonight with rain
steadily spreading west to east overnight. MVFR then IFR
cigs/vsbys will likely hold off until 16- 19z Wed.
.MARINE...A Gale Warning has been posted for Wednesday into Wednesday
evening. High pressure over the area this morning will bring quiet
conditions on the water today. East to southeast winds will ramp
up quickly later tonight in response to strong low pressure
approaching from the west. Gale force gusts to near 40kts are
expected on Wednesday, diminishing quickly Wednesday evening.
Waves will build quickly with the highest conditions here on the
west side of the lake. The low will pass south of Wisconsin Wed
night with high pressure and light winds expected on Thursday.
LM...GALE WARNING from 7 AM to 10 PM CDT Wednesday for LMZ643>646.
TODAY/TONIGHT AND AVIATION/MARINE...Davis
Wednesday THROUGH Monday...Collar