965 
fxus63 kmkx 202034 
afdmkx 


Area forecast discussion 
National Weather Service Milwaukee/Sullivan WI 
334 PM CDT Sat Mar 20 2010 


Short term/tonight through Tuesday... 


Tonight and Sunday...forecast confidence medium. 


Last bands of light snow should exit the far southeast by late this 
afternoon...as better isentropic lift and low level qg forcing sags 
to the southeast with baroclinic zone. Will decide on need for a 
pre-first period segment at issuance. 


Region remains under right rear quadrant of upper jet through this 
evening...with middle level qg convergence and 850-700mb frontogenetic 
forcing lingering over southern Wisconsin. However dry air continues 
to advect in behind departing trough with BUFKIT soundings showing 
depth of dry air sufficient to evaporate any lingering precipitation from 
this middle level forcing before reaching the surface...similar to what 
is happening in northwest Illinois under the 23dbz returns with no ground truth. 


Lingering clouds will hold low temperatures up in the south if they remain 
thick enough...with flow off Lake Michigan holding temperatures up in the 
upper 20s east....coolest temperatures northwest under mainly clear skies in the 
low 20s. 


High pressure to settle in with filtered sunshine Sunday through 
thin cirrus will help melt any remaining snow with soundings and 
925mb temperatures supporting near 50 highs in the west...but persistent NE 
wind holding eastern sites in the 40s. 


Monday and Tuesday...forecast confidence high. 


Ridging over the region between strong southern system and low 
dropping into the northern plains will keep southern WI dry through 
the day Tuesday. Light east wind will keep temperatures in the middle to 
upper 40s along the lake Monday with 50s inland. Thermal ridge 
ahead of plains trough brings 925 mb temperatures up to +9c Tuesday with 
all areas reaching 50s...though some cooling in the afternoon 
along the lake. Upper 50s to near 60 expected well inland. 


Long term/Tuesday night through Saturday...forecast confidence medium. 


European model (ecmwf) has a less amplified wave sweeping the northern states Tuesday 
night/Wednesday as it does not bring the stronger short wave 
ejecting out of the deepening SW U.S. 500mb low across the middle 
U.S. That the GFS does. Will keep slight chance probability of precipitation for trough 
passage. Then flow GOES zonal behind the Wednesday wave until Friday 
night/Saturday. After a warm Tuesday 925mb temperatures fall back some to 
+3 to +6c for Wednesday and Thursday. 


Going with the preferred European model (ecmwf)/European model (ecmwf) ensembles keeps surface high 
pressure over the region as weak short wave trough passes overhead 
Saturday...with better forcing and chance for precipitation north of County Warning Area. 
Will leave dry for now...but keep an eye on trends for either a 
stronger northern stream wave per the GFS...or the low European model (ecmwf) has to our 
south making any moves north. Going with the European model (ecmwf) brings cooler 
temperatures overall...with Cool Lake influence over eastern County Warning Area on NE wind 
flow. 




&& 


Aviation...drier air seeping into southern WI as high builds into 
Wisconsin should cause any remaining snow over the far southeast to 
push south and ceilings to rise. However some MVFR stratocumulus will 
remain until early this evening. Also 700 mb frontogenisis will 
continue along baroclinic zone into the evening...so cloud band 
will be slow to clear. 




&& 


Marine...tight pressure gradient between low pressure moving from 
eastern Arkansas to the Ohio River valley was generating brisk 
northeast winds. As high builds into Wisconsin the winds will 
diminish. High waves caused by strong northeast winds will take 
a bit of time to ease below small craft criteria. 




&& 


Mkx watches/warnings/advisories... 
WI...none. 
Lm...Small Craft Advisory until 3 am CDT Sunday for lmz645-646. 


Small Craft Advisory until midnight CDT tonight for lmz643-644. 


&& 


$$ 


Short/long term...09/rem 
aviation/marine...06/hentz