Weather

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fxus63 kmkx 052033 
afdmkx 


Area forecast discussion 
National Weather Service Milwaukee/Sullivan WI 
233 PM CST Monday Jan 5 2009 


Short term... 
tonight- 
surface high slides from Ohio Valley into northeast tonight. 
Subtropical plume along surface front coastal Texas into Carolinas 
should stay well south...but clouds likely to start sneaking in 
from the northern plains later tonight. 


Tuesday- 
warm conveyor belt surges up Ohio River valley but south of 
Wisconsin. Low pressure does not organize in time with first 
trough to throw precipitation back northwestward into 
Wisconsin...so it will be dry except perhaps far southeast. 


Wednesday- 
potent vorticity maximum races from Minnesota to near Milwaukee. 
Strong 500 mb height falls and differential positive vorticity advection may overcome 
marginal moisture in column to produce light snow. Moisture likely 
to be present in dendrite growth zone which could help beef up 
snow production some. 


Thursday- 
high pressure building into Midwest should provide quiet weather 
for southern Wisconsin. 


Long term... 
Friday- 
another potent upper trough races into area in northwest flow. 
Appears that more significant precipitation threat with this 
system...perhaps several inches of snow. Recent model runs have 
trended warmer...with GFS suggesting period of freezing rain or 
sleet near Illinois border. European model (ecmwf) is colder...but does hint at 
potential for sleet in the south. At this point will keep it all 
snow but this trend needs to be watched. 


Saturday- 
winter returns. Deep vortex moves across Ontario with 40-50 knot 
northwest flow at 850 mb helping readings crash to near -20c. 
Certainly could be situation where temperature does not rise much 
from Friday night low and we could be in single digits most of the 
day with wind chills at advisory levels. 


Sunday- 
subzero lows possible with 1000-500 mb thickness approaching 500 
dm. Arctic high moves into Midwest so winds start to diminish. 


Monday- 
European model (ecmwf) brings a low across Iowa into southern Wisconsin by Monday 
night...which could bring more snow. 1000-500 mb thickness barely 
gets to 520dm...so this would be a fluffy 20:1 snow event. 


&& 


Aviation... 
VFR conditions expected through 18z Tuesday as high pressure moves 
through the region. Next weather system to impact aviation 
operations will arrive late Tuesday afternoon into Tuesday night as 
low pressure moves through the lower Ohio Valley with a low pressure 
trough stretching north through the Great Lakes. There is still some 
uncertainty about how quick the low clouds will filter into 
southeast Wisconsin since they will be coming from two separate 
weather systems. At this time...it looks like MVFR ceilings will impact 
the region a little after 00z Wednesday. 


&& 


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


$$ 


Short/long term...Craven/02 
aviation/marine...cronce/13