597 
fxus63 kmkx 212011 
afdmkx 


Area forecast discussion 
National Weather Service Milwaukee/Sullivan WI 
311 PM CDT sun Mar 21 2010 


Visible satellite imagery revealed remaining snow over southwestern 
sections of County Warning Area from southern Dane County...across Green County into 
Lafayette County after hi/middle clouds finally settled to the south 
between 15z and 16z. Imagery showed rapid melting of snow through 
the midday hours...except the locations that saw 3-4 inches of snow 
in south central/southeast Lafayette County. 


Short term/tonight through Wednesday... 


Tonight through Monday night...forecast confidence high. 


Dry weather as short wave ridging and surface high pressure build over 
the region. Dew points under core of high that will settle over County Warning Area 
lower than on MOS guidance...so will undercut guidance for lows 
tonight. Also little chance of fog...except possibly over isolated 
locations that may still have snow. 


Temperatures will begin to rebound Monday...though northeast to east 
winds will make it tough for locations along and east of The Kettle 
Moraine to reach 50f...with low to middle 40s along the lake. Some 
increase in dew points west Monday night with developing southerly 
wind ahead of approaching weak surface trough should bring low temperatures 
up closer to guidance...with east winds off the lake keeping 
readings there in the middle 30s. 


Tuesday and Wednesday...forecast confidence high. 


Nice thermal ridge at 925mb with southerly winds ahead of trough 
will boost temperatures to near 60 except the eastern-most counties with 
onshore winds. Some frontogenetic forcing with trough/wind shift 
line...but no deep layer moisture and meager Omega so no precipitation 
expected. Little to no cold air advection behind trough so low to 
middle 30s for lows Tuesday night. +3c to +4c 925mb temperatures for Tuesday 
yield low to middle 50s away from the lake...with north winds bending 
onshore in the afternoon to keep temperatures in the low to middle 40s. 


Long term/Wednesday night through Sunday...low confidence. 


Weak cold front sags through on Thursday with stronger frontogenetic 
forcing than Tuesday but similar to Tuesday with only some low level 
moisture convergence and weak Omega along the surface front...no 
deep layer moisture for precipitation so expect a dry frontal passage. 


High pressure of Arctic origin building down for Thursday night and 
Friday. Though brunt of cold air shunts off to the east...will still 
be on the southern edge of the colder air with sub-5400m 
thicknesses. Models diverge on handling system for the weekend with 
all taking a more northerly solution with each run...the GFS showing 
a deeper closed low vs the sheared low along a tight baroclinic zone 
on the European model (ecmwf)...similar to what occurred yesterday but warmer. A 
blend between the 00z GFS/00z European model (ecmwf)...with a lean more toward the 
European model (ecmwf)...will be followed for now with temperatures warm enough for 
rain. Will watch later runs for possible snow with accumulations if 
the colder/stronger look of the GFS pans out and shifts a bit more 
to the north. 




&& 


Aviation...clear skies will dominate throughout most of the taf 
period...only possible clouds would be a few high cirrus late 
tonight and tomorrow...but opted to leave out of tafs. Modest low 
level mixing and continued dry surface conditions are expected to 
keep fog from developing across the majority of the County Warning Area...but very 
patchy fog in low areas could still be possible. 




&& 


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


$$ 


Short/long term...09/rem 
aviation/marine...16/Kuhlman