Weather

605 
fxus63 kmkx 062042 
afdmkx 


Area forecast discussion 
National Weather Service Milwaukee/Sullivan WI 
342 PM CDT Sat Sep 6 2008 


Short wave that brought light rain and sprinkles to mainly western and 
northern portions of County Warning Area last night is near ssm. An interesting sign 
of autumn was the band of clouds over Lake Michigan this morning 
on visibility satellite. With the lake waters and near surface air temperatures warmer 
than inland air temperatures...land breeze set up a north to south 
convergence zone over the lake...and produced the cloud band. 
Trailing vorticity lobe from exiting short wave enhanced the lift 
and popped a few showers within this band over the eastern section of 
the lake and lower Michigan. 


Short term...for tonight...similar situation to last night with 
short wave approaching from SW Iowa on water vapor loops. 
Operational models...as well as cras forecast water vapor loops 
track this wave to our south keeping most of southern WI dry. 
However...NAM forecast soundings for rfd show some elevated 
instability and moisture so will put a chance along the border for 
late tonight and a slight chance for the remainder of County Warning Area as second 
wave approaches region. 


Energy with this second wave farther north...but some 850 mb thermal 
ridging and isentropic lift along with low-middle level q vector 
convergence to keep chance probability of precipitation in play for Sunday. Tweaked cooler 
met numbers down a bit due to precipitation. 


Cold air advection behind wave pushes 850 mb baroclinic zone into 
northern Illinois Sunday night before stalling overnight. Deeper more dynamic 
wave under right entrance region of upper level jet moves across 
region for Monday. Favored NAM model tracks surface and 850 mb low 
southeast of WI...clipping the southeast corner...placing southern WI under 
shield of steady moderate rain. Precipitation most likely Monday afternoon 
into the evening with sloped frontogenetic forcing. Again sided 
with cooler met temperatures for Tuesday hi/S. 


Long term...short wave ridging in wake of trough brings a dry Tuesday and 
Wednesday. Warm air advection advection ahead of another deep wave over will bring a 
slight chance of showers and thunderstorms to far western County Warning Area Wednesday 
afternoon and County Warning Area-wide Wednesday night. Have hi chance probability of precipitation for Thursday 
with trough...but would not be surprised to see higher probability of precipitation in 
subsequent runs. Dry Friday and Saturday. Blend of mex/HPC 
guidance for temperatures in the extended. 






&& 


Aviation...VFR cumulus field will dissipate this evening. Will keep 
things VFR through this Sunday morning as well. Middle and high level 
clouds spreading east-northeast from Iowa ahead of next wave. Will increase the 
middle clouds during the night but low levels...from soundings/relative humidity 
progs/MOS...look dry and models suggest bulk of energy/lift will 
stay just south of WI. Some middle level relative humidity lingers into Sunday 
morning. 




&& 


Mkx watches/warnings/advisories... 
WI...none. 
Lm...none. 
&& 


$$ 


Short/long term...09 
aviation/marine...10