Weather

952 
fxus63 kmkx 102046 
afdmkx 


Area forecast discussion 
National Weather Service Milwaukee/Sullivan WI 
346 PM CDT Friday Oct 10 2008 


Forecast focus remains on warmer than normal temperatures for the 
weekend. 


Currently...warm air advection underway ahead of deepening western 
trough...with thunder over the eastern Dakotas/far western Minnesota in region of 
best 850-700mb frontogentic forcing and strongest isentropic lift on 
300k surface. Some middle/hi clouds in MO/southern Illinois lifting NE ahead of short 
wave located in eastern Kansas at 19z on water vapor imagery. 


Short term... 
cras infrared forecast imagery shows MO/southern Illinois clouds moving into County Warning Area 
after 03z...but BUFKIT soundings and large condensation pressure 
deficits on isentropic surfaces indicated only scattered-broken thin cirrus 
overnight as short wave weakens as it moves into mean ridge position. 
Lack of significant cloud cover and trajectories favor MOS guidance 
numbers for tonight. 


Soundings do not quite mix up to 850mb level Saturday...but using 
925mb technique yields hi temperatures Sat closer to warmer mav numbers in 
the middle/upper 70s for inland locations...with cooler temperatures Lakeside 
with southeast winds. Expect temperatures to hold up Sat night with enough surface 
gradient and turbulent mixing with 20-25kt srly winds just off the 
surface to prevent decoupling. Sunday 850 mb temperatures of +14c mix down 
to lower 80/S at the surface...though expected thin cirrus deck 
enough to hold temperatures closer to upper 70s to around 80. Afternoon 
cooling expected along the lake as surface winds turn southeast. 


Slower movement of western trough keeps western Great Lakes under influence of 
ridging through Sunday night and into Monday. Have limited slight 
chance probability of precipitation to just the western County Warning Area during the day Monday...then hi 
chance probability of precipitation across County Warning Area Monday night and Tuesday. Lines up well with 
enhanced clouds on cras infrared imagery. 


Long term... 
GFS and European model (ecmwf) diverge greatly in handling western trough. European model (ecmwf) ejects 
significant portion of energy into northern stream across northern plains 
toward Hudson Bay...then opens up southern portion of trough and tracks it 
across Midwest Tuesday night into Wednesday as an open wave. GFS keeps 
closed circulation intact into the plains that takes on a negative 
tilt as it lifts into southern Ontario Tuesday afternoon. 00z and 12z 
Canadian model runs favor the European model (ecmwf)...while 12z NAM leans toward GFS 
though faster and farther north at 84 hours (00z tue). 


Went with HPC blended solution which keeps precipitation chances into Wednesday as 
second wave develops along surface front and moves just south of state 
Tuesday night...then secondary cold front sweeps across region during the 
day Wednesday. Went with a blend of mex MOS and HPC numbers for temperatures. 


&& 


Aviation...VFR conditions will persist. There is a possibility of 
low level wind shear overnight tonight. South-southeast winds 20 to 30 knots just above the surface are 
forecast by a couple of the models around 03-06z. Will need to keep an 
eye on the developing conditions. 




&& 


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


$$ 


Short/long term...09 rem 
aviation/marine...13 mrc