209 
fxus63 kmkx 230943 
afdmkx 


Area forecast discussion 
National Weather Service Milwaukee/Sullivan WI 
343 am CST Monday Nov 23 2009 


Forecast focus on fog and clouds today...system for Tuesday 
through Thanksgiving day. 


Latest water vapor imagery indicated an upper low over 
Montana...with a downstream shortwave trough from southeast South 
Dakota to southern Missouri. At the surface...high pressure was 
found east of Maine...with its axis extending west into southern 
Wisconsin. Area of light rain and drizzle associated with low 
level frontogenesis was found from western Wisconsin to central 
Iowa. 


Today and tonight...high clouds streaming into the area from the 
south. In addition...area of low clouds has formed across the 
eastern counties...which has brought visibilities with the fog out 
of dense fog criteria. This area of clouds should persist through 
the morning with the expected light winds and temperature 
inversion. So...not expecting widespread dense fog...and have 
cancelled the dense fog advisory for the eastern counties. Still 
may be patchy dense fog during the early morning hours. 


Should see some breaks in the high clouds today across the western 
counties...and in the afternoon in the east. Highs should remain 
mild...and reach the lower to middle 50s across the area. Fog 
expected once again tonight with light winds and lingering low 
level moisture under the temperature inversion. The expected low 
stratus should limit any dense fog to isolated areas. 


Tuesday through Thanksgiving day...continued to follow the 
consistent European model (ecmwf) model with the system expected to affect the area 
during this period. Surface low will move from near Kansas City to 
southeast Iowa on Tuesday...then into southern Wisconsin Tuesday 
night. Low to middle level frontogenesis with this system moves 
northeast through the area Tuesday through Tuesday night. Expect 
area of rain to move into the area mainly Tuesday afternoon and 
Tuesday night. Upper low moving through the area Tuesday night 
also helping with the upward vertical motion fields. Kept likely 
probability of precipitation for Tuesday afternoon and Tuesday night. 


The low then moves northeast to Northern Lake Michigan 
Wednesday...with a trough axis shifting southeast through the area 
Wednesday night into Thanksgiving day. Another upper low shifts 
eastward from Iowa to northern Illinois Wednesday night...then 
east on Thanksgiving day. Low to middle level frontogenesis band does 
shift across the area during this time. 


Colder air moves southeast through the area later Wednesday and 
Wednesday night. However...925mb temperatures and forecast 
soundings show precipitation type should remain all rain 
Wednesday...perhaps changing to a mix Wednesday night and 
Thanksgiving day. Current thinking is to have likely probability of precipitation through 
Thanksgiving day...but leave a rain to a mix transition during 
this time. It does not look like accumulating snow is possible 
given the warm low level temperature profiles. Stay tuned... 


Thursday night through Sunday...upper low shifts out of the 
region Thursday night and Friday...with lingering low probability of precipitation. Quiet 
weather then expected into next weekend with a high pressure Ridge 
Crossing the area. 


&& 


Aviation...an IFR to LIFR stratus deck has developed over southeastern 
WI and will develop westward into portions of south central WI this am. 
IFR to MVFR visibilities will prevail as well with local LIFR visibilities. The 
stratus and fog will persist this am and begin to improve by middle 
morning. Localized MVFR stratus and visibilities may linger into the 
afternoon with only light Ely winds and little mixing to improve 
conditions further. 


A light southeasterly flow and good radiational cooling will persist again 
tonight with stratus and fog formation once again. IFR visibilities will 
prevail with LIFR to vlifr in low lying areas. Scattered-broken stratus 
will likely develop with broken stratus in the IFR to vlifr range. 


&& 


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


$$ 


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