942 
fxus63 kmkx 210922 
afdmkx 


Area forecast discussion 
National Weather Service Milwaukee/Sullivan WI 
322 am CST Sat Nov 21 2009 


Forecast focus on dense fog this morning...quiet weather into 
Monday night...precipitation chances Tuesday through Thanksgiving 
day. 


Latest water vapor imagery indicated an upper trough shifting into 
the western USA...with a downstream upper ridge over the upper 
Midwest...and a shortwave trough over northern Indiana. At the 
surface...high pressure was centered over southern Ohio. 


Today...light winds and clearing skies helping fog form across 
south central and portions of southeast Wisconsin early this 
morning. Some middle level clouds lingering in the northeast counties 
may limit the fog somewhat early...but these clouds should 
dissipate within a few hours. RUC forecast soundings across the 
area through 15z this morning show a decent temperature inversion 
just above the surface. 


However...moisture profile in the low levels not saturated...so 
some question as to if dense fog will occur other than in the 
Wisconsin River Valley. Lowest visibilities not expected until the 
11z to 14z time frame...so will give current dense fog advisory for 
the far western counties and Green County more time. 


After fog dissipates later this morning...expect a pleasant day 
under the influence of the high to the southeast. Mostly sunny 
skies and mild temperatures are expected...with highs in the 
lower to middle 50s. 


Tonight through Monday night...followed the consistently drier 
NAM/European model (ecmwf) models for this period. The high slowly moves further 
east of the region...with a confluent zone setting up from 
northwest Wisconsin southwest to Iowa and Nebraska. Any light 
precipitation from this area will stay west of the forecast 
area...as dry airmass in place holds steady. 


Mentioned patchy fog tonight and Sunday night...with solid low 
level temperature inversion over the area. Mild temperatures to 
continue through the period...with a gradual increase in clouds 
Monday and Monday night ahead of next system. 


Tuesday through Friday...continued to follow the ecwmf model for 
this period...preferred by HPC. This continues to show 
cyclogenesis over southeast Nebraska Monday night...then moves the 
low slowly east northeast to northern Illinois by 12z 
Wednesday...then to the Eastern Upper Peninsula of Michigan by 
12z Thanksgiving day. Strong upper low accompanies the surface 
low. 


Best low level frontogenesis and quantitative precipitation forecast comes across the area Tuesday 
and Tuesday night...with weaker upward motion and quantitative precipitation forecast Wednesday 
through Thanksgiving day. Adjusted probability of precipitation accordingly for this 
period. Looks warm enough for all rain Tuesday through Wednesday. 
925mb temperatures get cold enough for a mixture of rain and 
snow Wednesday night into Thanksgiving day...but am not expecting 
much in the way of accumulating snow at this time. 


&& 


Aviation...a high pressure ridge will move eastward across southern WI 
today with southerly winds developing tonight and sun as the high moves east 
of the region. Radiational fog will prevail through 15z this am 
with IFR to MVFR visibilities expected at the taf sites over south 
central and southeast WI. Light radiational fog will develop once again 
late tonight around 09z sun but mainly remain MVFR visibilities. Isolated IFR 
visibilities may occur especially at kenw. 


&& 


Mkx watches/warnings/advisories... 
WI...dense fog advisory until 10 am CST this morning for wiz056-062- 
067-068. 


Lm...none. 
&& 


$$ 


Short/long term...08/wood 
aviation/marine...20/gehring