Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 231600
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1000 AM CST Mon Jan 23 2017
.AVIATION/18Z TAFS/...Surface ridging continues to build into WI
with plenty of lingering low level moisture. Stratus is widespread
and there are some pockets of IFR and LIFR vsbys. Cigs are
straddling LIFR and IFR. Some improvement with the vsbys into the
aftn. Surface high settles across tonight with overall light wind
regime. SREF and MOS suggest dense fog less likely than the last
few nights. But given these low cigs it doesn`t take much to get
some thicker fog here and there with the overnight cooling. Not
expecting any precip through at least 18z Tuesday. Then srn WI
likely to see pcpn develop during 18-21z time frame Tuesday
afternoon as waa regime sets up ahead of next low. Boundary layer
looks warm enough for rain though some flakes possible too.
.MARINE...South winds and waves will approach small craft advisory
conditions Tuesday night and Wednesday morning, as low pressure
moves into the Wisconsin/Illinois border area. Northwest winds may
approach small craft advisory levels Wednesday night in the wake
of the low.
.PREV DISCUSSION... /Issued 327 AM CST Mon Jan 23 2017/
TODAY AND TONIGHT...Forecast confidence is medium.
The drizzle around the area this morning should dissipate early as a
mid level trough pushes through. Surface ridging arrives this
afternoon and tonight with low level moisture remaining quite deep
at 4-5kft. We don`t expect any decent clearing through the period
given the weak flow regime. Our small diurnal temp trend will
continue with highs getting up to around 40 today and lower 30s
TUESDAY THROUGH WEDNESDAY... Forecast confidence is medium.
Low pressure will track across IA and southeast WI. There is fair
agreement between the models on the track, but the axis of highest
qpf is still uncertain. WPC continues to favor the steadier ECMWF,
so leaned in that direction as well. Precip will be fighting dry
easterly flow, so it might take a while to reach Milwaukee. The
overall synoptic forcing is quite strong over southern WI Tue night,
so precip should be showery. Can`t rule out a rumble of thunder.
Precip will begin as rain in south central WI Tue afternoon, but
quickly transition to snow by late Tue evening as it overspreads all
of southern WI. Temperatures aloft will warm a little across south
central and southeast WI as the surface low tracks through southeast
WI. Expect snow to change over to rain in Milwaukee and Janesville
and southeast late Tue night. There will be a sleet/rain/snow mix
within that transition between all snow and all rain.
Because of the mild temperatures, not all the snow that falls will
stick to pavement, but snowfall rates should be high enough for 2-4
inches of a wet snow Tue night for areas north of Madison to
Sheboygan. This would impact the Wed morning commute.
We are expecting snowfall totals for the 24-hr period from Tue
evening through Wed afternoon in the 3 to 6 inch range northwest of
a line from Madison to Sheboygan, so a winter weather advisory is
looking likely. An inch or less is expected in southeast WI
THURSDAY THROUGH SUNDAY... Forecast confidence is medium.
Cooler cyclonic flow will continue overhead through the weekend.
This will keep clouds in place and the chance for light snow showers
across southern WI at times. Light snow showers are expected
Thursday afternoon or evening with a weak shortwave trough tracking
through the region.
MONDAY THROUGH TUESDAY... Forecast confidence is medium.
Another low is expected to drop down from south central Canada and
bring a chance for light snow to WI Monday night into Tuesday.
The deep low level moisture will remain in place through the TAF
period, resulting in IFR CIGS persisting most places. The light
northwest flow could bring CIGS closer to lower MVFR levels for the
Lake Michigan shore area...including KMKE/KENW. Surface ridging,
with weak winds, pushes in this afternoon and tonight. This will
help to ensure the low clouds remain in place.
Northwest winds in the wake of a departing low pressure system
Wednesday into Wednesday night may approach small craft advisory
TODAY/TONIGHT AND AVIATION/MARINE...Davis
Tuesday THROUGH Sunday...MRC