Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 021609
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1009 AM CST Fri Dec 2 2016
Soundings and upstream obs indicate skies will remain overcast with
little increase in temperatures today. Dry weather is expected
through this period.
Model soundings and upstream observations indicate overcast skies
with 2500 to 3000 ft ceilings will persist through today and likely
into Saturday. Far eastern WI may see 3000 to 3500 ceilings at
times. High pressure should help dry out the atmosphere somewhat
improve ceilings Saturday afternoon or evening.
Northwest winds will weaken today and become westerly overnight.
Southwest winds should increase Sunday into Sunday night, veering
west later Sunday night. For now, it looks like the gusts will
remain a little below 22 knots.
There is a chance for sustained gusty winds and high waves starting
Tuesday night. However, there remains considerable uncertainty with
how things will evolve with systems moving through the region.
.PREV DISCUSSION... /Issued 248 AM CST Fri Dec 2 2016/
TODAY AND TONIGHT...Forecast Confidence Is Medium.
Narrow band of light rain and snow showers will continue to shift
east southeast across the area early this morning, in association
with a surface trough. There is also some light drizzle and flurries
lingering, so will take all of these east southeast through the area
until 12Z or so, when the trough moves out of the area.
Cyclonic flow with 500 mb low to the northeast of the region should
continue to move out of the region today, with more zonal flow
taking hold of the area into tonight. Area forecast soundings from
models suggest that low clouds should linger during this period.
Continued to go mostly cloudy for today into tonight. May need to go
more overcast with clouds later today into tonight, given upstream
observations and trends.
Temperatures should not rise much today, with the expected clouds
over the area. Went with middle 30s in most areas. Forecast lows
tonight in the middle 20s may be too cold, if clouds remain
SATURDAY - Confidence...High
A ridge of high pressure gradually shifts through this period. The
high will be situated over the Plains Friday and then shift across
the Badgerland on Saturday. Mid level flow will be west/northwest
with an increasingly anticyclonic look. So a quiet period though
cloud cover may be stubborn with low level trough still hanging
around with little in the way of thermal advection.
SUNDAY - Confidence...Medium
Models are all showing a mid level shortwave moving through. No real
surface or 850 low noted so more of a trough passage in the lower
levels. Some WAA ahead of the 850 trough. Needed to substantially
boost the woefully low superblend pops. Went even higher than the
consensus MOS as confidence is high that it will precipitate and
measure across the CWA. Models showing 0.10 to 0.20 inch of QPF
with this system swinging through. Bufkit soundings shows the ice
remaining in the column longer than prior runs so appears that the
snow may hang around longer with perhaps a transition to a mix of
rain and snow as the low levels nudge warmer with time. Have
nudged up expected snow amounts by a half an inch or so due to
expected longer saturation within the dendritic growth zone.
MONDAY - Confidence...Medium to High
Surface/850 anticyclone will be in place with building 500 millibar
heights expected. 850 WAA sets up though better forcing will be well
to our west with approaching low from the northern Plains.
Nevertheless the return southerly flow should allow temps to
reach or slightly exceed the 40 degree mark.
TUESDAY THROUGH THURSDAY - Confidence...Low
Potential for a couple rounds of precipitation prior to the arrival
of the coldest airmass of the season. There continues to be run to
run variability on the pattern of cyclogenesis within the advancing
large scale mid level troughing. With respect to the initial low
the GFS and ECMWF bring it into the Ohio Valley on Tuesday with
the consensus of the GFS/ECMWF showing 0.10 to 0.20 of qpf.
1000/500 millibar thicknesses and 850 temps suggest some mix
potential before transitioning to light snow. However confidence
is low on this as a further eastward trek of this low will result
in a more collapsed thermal profile, lower qpf overall but less
mix or rain. So this one will likely fluctuate between now and
then. The models then show an overall break Tuesday night into
Wednesday before another low arrives later Wednesday into
Thursday, and this one will really tap into the colder airmass.
This low will have an airmass more supportive of snow at the
outset. The 00z ECMWF has shifted much further east towards the
GFS solution. With this being still several days hard to fathom
there wouldn`t still be more fluctuations in the models. One thing
we can be fairly sure of is that we won`t escape the colder air
that will sweep in here for the end of the week.
AVIATION/12Z TAFS/...Narrow band of light rain and light snow
showers will continue to shift east southeast across the area
early this morning, exiting the Kenosha area around 12Z or so.
This is associated with a surface wind shift boundary moving
through the area. No accumulation is expected on runways. Some
light drizzle and flurries may linger as well until 12Z.
Ceilings should drop to 2000 to 2500 feet above ground level for
most of today into tonight at Madison and in western portions of
the area. Ceilings may be around 3000 feet or higher for a time
today in eastern portions of the area, including the eastern TAF
sites. There may be some reductions to 1500 feet or so at times
today at Madison.
West northwest winds are expected today, with some gusts to around
15 knots at times. Winds will become light tonight.
MARINE...Southwest winds should increase on Sunday into Sunday
night, veering west later Sunday night. For now, it looks like
the gusts will remain a little below 22 knots. High waves should
remain over the open waters.
There is a chance for sustained gusty winds and high waves Tuesday
night into the rest of next week. However, there remains considerable
uncertainty with how things will evolve with systems moving through
the region. It does appear that there may be a push of colder air
into the region later in the week, which may lead to Small Craft
Advisory level winds and building waves.
TODAY/TONIGHT AND AVIATION/MARINE...Wood
TODAY/TONIGHT AND AVIATION/MARINE...Wood
Saturday THROUGH Thursday...Collar