678 
fxus63 kmkx 200848 
afdmkx 


Area forecast discussion 
National Weather Service Milwaukee/Sullivan WI 
348 am CDT sun Jul 20 2008 


Discussion...main focus on rain chances today and Monday then 
next system for Thursday. 


Today- 
shortwave which brought the overnight rainfall is shifting east of 
the area. Looks like broadly cyclonic flow with sheared vorticity at 
best. Boundary interactions and instability will lead to keeping a 
slight chance in for today. Also seeing some redevelopment just 
north of County Warning Area in low level convergence zone with weak frontal zone. 
Soundings get rather unstable this afternoon but also noting 
quite a bit of dry air as well. For now will opt for the slight 
chance. Rainfall mixed up the fog a bit but still some visibilities at or below 
1sm...so will mention patchy fog early on. 


Tonight- 
some disagreement on placement of h2 jet core between GFS and 
NAM...but in either case some upper divergence is noted along with 
the arrival of the next shortwave. Models trending this next 
complex just southwest of the County Warning Area. Will have the highest chance 
probability of precipitation in the southwest and lowest in the northeast. 


Monday- 
upper trough starts to carve out with jet placement not as favorable 
but more defined cyclonic upper flow and several disturbances 
suggests keeping chances going. 


Tuesday- 
tricky here as GFS showing quantitative precipitation forecast with colder 500 mb temperatures especially 
across the eastern 1/2 of the County Warning Area. Both GFS and NAM soundings are 
not impressive and even the GFS 700 millibar relative humidity/Omega favor NE WI. 
Will hold off on introducing any rain showers at this time. 


Wednesday- 
upper ridging starts to take hold as trough moves further away. Will 
see modifying temperatures and confidence pretty good for a dry day. 


Thursday- 
what brief ridging there was transitions into more of a swift west-northwest 
upper flow with a pretty decent system targeting the County Warning Area. Boosted 
probability of precipitation a smidge. 


&& 
10 


Aviation...weak surface low pressure will slowly push east as weak 
high pressure builds into the region. Widespread IFR and low IFR 
ceilings with MVFR to IFR visibilities will persist until middle 
morning. Light westerly surface winds will improve ceilings and 
visibilities from west to east during the late morning hours with 
VFR conditions expected this afternoon and tonight. Widely scattered 
afternoon and evening convection may briefly produce MVFR ceilings 
and visibilities in stronger storms. 




&& 


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


$$