139 
FXUS63 KGRB 031124
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
524 AM CST Sun Nov 3 2019

Updated aviation portion for 12Z TAF issuance

.SHORT TERM...Today...Tonight...and Monday
Issued at 257 AM CST Sun Nov 3 2019

The main concerns in the short-term will be the rain/snow 
potential tonight into Monday along with continued below normal 
temperatures. Some slippery travel may develop for the Monday
morning commute, mainly northwest of the Fox Valley.

Satellite imagery shows widespread cloud cover lingering across 
much of the area, with some clearing occurring in west wind 
favored downslope locations. Radar was showing very little 
activity around the area with the exception of some lake effect 
snow across both Lower and Upper Michigan. Temperatures were being
kept a bit warmer with the continued cloud cover with most 
locations ranging form the mid 20s to the mid 30s. 

Today...The next small chance of precipitation will arrive this 
afternoon along and ahead of a weak vort max associated with 
southwest to northeast moving 700-850mb FGEN band/weak warm 
front. It looks like temperatures above 900mb would support snow; 
however, low-level temperatures are expected to warm into the 
upper 30s to low 40s, especially with the day starting warmer due
to overnight clouds. This would indicate a better chance of 
seeing mainly rain where it does precipitate, especially during 
the afternoon hours. Overall, not expecting much in the way of QPF
with the system today, in fact, most models are painting out very
little in the way of QPF as forcing and deep-layer moisture is 
not overly impressive. 

Tonight into Monday: A surface low is expected to shift from 
central MN early this evening to eastern Upper Michigan by 12Z 
Monday. This will allow the surface warm front to lift northward 
into much of northeast WI this evening. The warm front is expected
to quickly be followed by a cold front, which should pass through
the area between 06Z and 12Z Monday. At the same time, a vort max
is progged to slide from South Dakota through central WI. The 
forcing associated with these features will provide enough lift to
produce widespread precipitation. The more concentrated area of 
precipitation will likely remain across central portions of WI, 
where the better vort max is noted. Models are painting out around
0.10 to 0.25 inches of QPF across the area, lightest across 
north-central into far northeast WI, with the heaviest totals 
central into east-central WI. Thermal profiles show warmer low- 
levels across central into east- central WI tonight, which would 
lead to mainly rain with a few snowflakes possibly mixing in at 
times. 

Farther north, across north- central WI and far northeast 
WI, thermal profiles support mainly snow. This would end up giving
an inch or so of accumulation up that way, while much of central 
and east-central WI sees little to no snow accumulation. The minor
accumulation may make for some slippery travel northwest of the
Fox Valley Monday morning. The aforementioned surface low will 
shift farther eastward into southern Ontario by Monday afternoon. 
This will keep cyclonic flow in place across much of the area 
along with some lingering wrap- around moisture. At the same time,
much of WI will be under the 500mb trough axis. This will keep a 
lingering chance of rain/snow showers through much of the day. 
Surface to 850mb winds are expected to be out of the northwest 
Monday afternoon, which may lead to some lake effect snow chances 
developing across northern Vilas County. Only minor additional 
accumulations are expected. Temperatures are expected to be in the
in the mid 30s central/east- central to mid 20s north-central and
far northeast. High temperatures are forecast to be in the upper 
30s to low 40s for Monday.

.LONG TERM...Monday Night Through Saturday
Issued at 257 AM CST Sun Nov 3 2019

The 500mb ridge off the west coast of North America will expand
eastward across the western half of North America later in the 
week. Meanwhile, a downstream trough at 500mb will remain across 
the central and eastern United States. Below normal temperatures 
are expected through the period along with periodic chances for
rain and snow. 

For Monday night, weak high pressure will build into the region. 
There is still a small chance of light snow across the north. A
few lingering lake effect snow showers are possible across the far
north Tuesday morning. High pressure moves across the area Tuesday
afternoon, and then east of the state Tuesday night. Meanwhile,
a potent system will move towards the area Tuesday night and then
across the western Great Lakes region on Wednesday. Models 
indicating strong 850mb warm advection, while a strong 300mb jet 
streak (145 knots) will pass north of the state late Tuesday night
and Wednesday morning. The forecast area will be in the favored 
right entrance region of the jet to enhance the lift. At this 
time, it appears that several inches of snow are possible. There 
is still some uncertainty in the track of the storm, amount of 
warm air working into the region ahead of the system, and 
associated precipitation amounts that could impact snowfall 
totals. Will continue to mention this system in the Hazardous 
Weather Outlook (HWO). Per the ECMWF, most of the snow should 
exit the area later Wednesday morning with high pressure building 
into the region Wednesday afternoon and Wednesday night. 

Behind the system, a 1040+ mb Canadian high pressure system will 
drop south into the northern plains on Thursday. It now appear 
that the first widespread day with high temperatures below 
freezing are expected with highs in the 20s to around 30. The
chances of lake effect snow showers will linger across the far
north Thursday night into Friday morning. Otherwise, mainly dry 
and cold conditions expected Friday and Saturday. High 
temperatures on most days will run 5 to 15 degrees below normal.
&&

.AVIATION...for 12Z TAF Issuance
Issued at 524 AM CST Sun Nov 3 2019

A brief ridge of high pressure will continue to shift off to the
east of the area this morning. Stubborn low stratus has lingered
at all of the TAF sites and will likely do so throughout this TAF
issuance. High end VFR conditions have been noted at RHI, while
most of the rest of there area has seen ceilings around 3.5kft.
There may be a few breaks in the clouds this morning; however,
this will be short-live as the next batch of mid to high clouds
are already approaching from MN and the Dakotas. A low pressure
system and frontal boundaries will pass through the area tonight,
allowing for a rain/snow mixture at each of the TAF sites. The
best chance of seeing mainly snow will be at AUW, CWA and RHI.
Both ceilings and visibilities are expected to be reduced even
lower tonight, with some IFR conditions expected.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....Cooley
LONG TERM......Eckberg
AVIATION.......Cooley