838 
fxus63 kgrb 201033 
afdgrb 


Area forecast discussion 
National Weather Service Green Bay WI 
533 am CDT sun Jul 20 2008 


Short term...50-60 knots jet will move from North Dakota to southern 
Wisconsin today....with left exit region moving across the northern 
part of the state. Favorable jet position and colder temperatures 
aloft should make thunderstorms prevalent in the northern part of 
our forecast area this afternoon. There will also be scattered 
showers and thunderstorms along nearly stationary boundary across 
central Wisconsin. Fairly strong winds aloft...low wet bulb zero 
heights and decent low level moisture should make for a few strong 
to severe thunderstorms this afternoon and early evening...and the 
Storm Prediction Center has our area in the day one slight risk. 


Additional jet energy comes through tonight and Monday. Drier air 
arrives in the low levels from the north...but there seems to be 
sufficient upper support to warrant at least a chance of showers 
and thunderstorms tonight and Monday. Northern Wisconsin should 
have the best chance as it is closest to cold air aloft and upper 
forcing. 


Long term...Monday night through Saturday. Precipitation chances 
are the main concern during this part of the forecast. Upper level 
flow is forecast to become more amplified early next week with a 
trough east of the state and a ridge developing in the central 
Continental U.S.. have added probability of precipitation for Monday night in cyclonic flow around 
the departing surface low and upper level short wave. Dry weather 
is expected for a while as high pressure and an upper ridge build 
into the region. The ridge eventually flattens...resulting in more 
zonal flow and another chance of thunderstorms with a surface 
system approaching from the plains. 
&& 


Aviation...IFR/VFR ceilings and visibilities should gradually give way to 
VFR weather this afternoon. Because of the scattered nature of the 
storms...they may not be mentioned in the tafs. 
Rhi/arv/aig/imt/mnm/sue/aig airports have the best chance of 
seeing storms...with lesser chances to the south. Persons 
attempting VFR flying over Lake Michigan may have trouble seeing 
the lake and Lakeshore areas due to dense fog today. 
&& 


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


$$ 
Rdm/mg