Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 131019

Area Forecast Discussion
National Weather Service Green Bay WI
519 AM CDT Tue Mar 13 2018

Updated aviation portion for 12Z TAF issuance

.SHORT TERM...Today...Tonight...and Wednesday
Issued at 246 AM CDT Tue Mar 13 2018

Cold cyclonic flow was already generating snow showers and
flurries across the far north with visibilities between 1 to 3
miles over a few locations over Vilas County. Forecast issue
today centers on coverage of the light snow showers and flurries
as Height 850 temps drop to around -16C this afternoon. Satellite
imagery shows mid level clouds working over the previously clear
conditions over east central Wisconsin early this morning. LFQ
region of the upper jet was sliding over early this morning.

The cold upper trough is expected to nudge to the east this
evening with a weak warm air advection pattern developing later
tonight into Wednesday morning as a weak frontal system drops
over the state wednesday. A few snow showers may begin to work
into far northeast Wisconsin later Wednesday afternoon near a
progged weak surface low combined with daytime heating. Another
jet let drops over the area Wednesday, but will continue the dry
forecast at this time due to a dry air mass.

Low temperatures tonight may be more of an early night low before
turning steady, especially if clouds can develop along and ahead
of the weak warm front.

.LONG TERM...Wednesday Night Through Monday
Issued at 246 AM CDT Tue Mar 13 2018

With a deep trough anticipated to be present over the eastern U.S.
through the week, quiet conditions can be expected over the western
Great Lakes, which will be positioned just downstream of a mid-level
ridge axis.  Once this ridge axis passes, precipitation chances are
anticipated to ramp up late this weekend into early next week.  Will
use a blend of the gfs and ecmwf for much of this forecast.

Wednesday night through Thursday night...High pressure will be
building south out of Canada and into the region over the period. As
this occurs, cold advection will be occurring, dropping 850mb temps
into the mid teens below zero over northern WI and Lake Superior.
With a sharp inversion present and unstable conditions, think will
see some clouds arrive from the north, particularly over northern
and eastern WI. Scattered light snow showers and flurries also look
to be possible in the snow belt of Vilas county, and probably over
far northeast WI too on late Wednesday night through Thursday
morning.  Clouds will most likely depart on Thursday night as high
pressure and dry low level air arrive.

Rest of the forecast...The high pressure system will stick around
for a few days, providing mostly clear conditions and seasonable
temps into Sunday.  With a light east wind, some lake clouds could
drift into the east-central WI shoreline on Friday and Friday night.
Clouds will finally return late Sunday with a chance of precip on

.AVIATION...for 12Z TAF Issuance
Issued at 519 AM CDT Tue Mar 13 2018

An upper level disturbance dropping southward, combined with
colder air pouring over the area on blustery north winds, will
produce scattered MVFR cigs and vsbys due to snow showers. The
snow showers may be more numerous over north central Wisconsin
for much of today. Conditions to improve VFR levels tonight
along with diminishing northwest to west winds.



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