958 
fxus63 kgrb 092129 
afdgrb 


Area forecast discussion 
National Weather Service Green Bay WI 
329 PM CST Friday Jan 9 2009 


Short term...tonight through Saturday. Surface low about 100 
miles north of Tulsa at 2100 UTC forecast to move to Missouri 
bootheel and then to northern Kentucky by Saturday afternoon. 
Strong baroclinic zone and good upper support is producing 
snow/sleet/freezing rain well north of the surface system...but 
too far south for US. There could be some lake effect snow showers 
along the Lake Michigan shore south of Kewaunee later tonight 
through noon staurday as low level winds become northeast. Not 
expecting much though...as the air is dry and the 850mb to lake 
water difference is not that great. Otherwise some middle and high 
clouds may move across the southern half of the forecast area 
tonight with mostly clear skies in the north. Went colder than MOS 
guidance tonight since there should be more clear skies than 
models are forecasting. 


Long term...Saturday night through Friday 


Tranquil pattern expected Saturday night before weak surface 
trough pushes through the state on Sunday. This feature will 
bring a chance of light snow to the forecast area. On Sunday 
night...previous forecast went dry and will continue that trend 
as the surface trough pushes east of the state. 


Attention turns to the cold weather that will arrive 
on Tuesday. Models have slowed down the core of the cold 
air until Wednesday into Friday as clipper system expected 
to pass south of Wisconsin Tuesday and Tuesday night. 
Based on pattern recognition and looking at the 850mb 
thermal profile on the models...this clipper system will 
move out of the northern rockies and then dive southeast. 
Models also hinting at dry Arctic high pressure north of 
Wisconsin. Despite the models cranking out light precipitation 
Tuesday and Tuesday night over the entire forecast area...only 
went with a small chance of light snow over the south. Belief is 
that Arctic high will bring a sharp cutoff to the snow as the clipper 
system draws in the dry cold air from the northeast. Similar to the 
clipper system that passes well south of Wisconsin today. 


Once the clipper system pushes east of Wisconsin Tuesday night... 
the core of the cold air will sweep across Wisconsin and then 
continue into Friday. A slow moderation in temperatures is 
expected for the following weekend. Wind chill advisories or 
warnings will likely be needed at some point between Tuesday 
and Friday. If winds go calm and skies are clear...Thursday 
night may be the coldest night across the area since 1996 with 
readings approaching 20 below in Green Bay and the Fox Valley 
and could be close to 30 below up north. Current forecast package 
is a little more moderate in the cold...but the potential is there 
to see those extreme readings. 
&& 


Aviation...generally VFR weather expected tonight and 
Saturday...with local MVFR ceilings near Lake Michigan if lake effect 
snow showers materialize. 
&& 


Grb watches/warnings/advisories... 
none. 
&& 


$$ 
Rdm/eckberg