419 
fxus63 kmpx 192307 
afdmpx 


Area forecast discussion 
National Weather Service Twin Cities/Chanhassen Minnesota 
505 PM CST Wednesday Nov 19 2008 


Updated for aviation discussion below... 


Discussion... 
widespread SC across area this afternoon...but a few breaks in wc Minnesota 
and more numerous break across north Minnesota. Feel than mostly cloudy 
wording will reflect prevailing conditions overnight. Satellite 
imagery showing vorticity maximum diving southeast into Saskatchewan which is prognosticated by 
models to near Mot by 06z and then into wc Minnesota by 12z. This feature 
has been producing --sn and it should increase the chance of --sn 
tonight into Thursday morning in area. Main push of cold advection 
underway now...but steady but rather weak cold advection continuing 
overnight. Based on MO cloudy forecast...some wind continuing and 
trajectories from last nights min temperatures went just a bit 
higher than guidance on lows for tonight. Should see more numerous 
breaks in overcast developing tomorrow in subsidence behind vorticity 
which will be moving through area. 850 mb relative humidity forecasts also do show some 
drying. With strong 1000-850 mb lapse rates still will be potential 
of -shsn in afternoon. 


Models all show trough approaching northwest coast now bringing some chance 
of -sn mainly to SW areas Friday night and early Saturday morning. 
GFS/NAM solution would affect only SW Minnesota...but European model (ecmwf) a bit farther 
north. Will continue with probability of precipitation pretty much as is...but just add a 
slight chance for SC Minnesota for Saturday morning. Models do show this 
wave weakening as it moves through area encountering more confluent northwesterly 
flow. 


GFS has trended a bit stronger and European model (ecmwf) more northerly on track of 
next trough for Sunday/Sunday night. We have been carrying only 
small probability of precipitation in SW areas with this system...and will let them ride for 
now. Better chances will be in NE County Warning Area...but doesn't look too 
impressive for much snow. 


&& 


Aviation.../00z taf issuance/ 
mainly MVFR ceilings through about 17z Thursday across most taf sites. 
Remaining cold air advection over the region this evening with surface high building east 
into the Dakotas/western Minnesota. As this moves closer believe northwest winds 
will gradually lose there gustiness...certainly after 18z Wednesday from 
west to east over the forecast area. Model trends indicate drier air moving 
into the region later tonight and Thursday morning. Believe this 
should lift ceilings some and eventually break them out Thursday afternoon. 
Did go scattered developing after 20z most areas. 


&& 


Mpx watches/warnings/advisories... 
Minnesota...none. 
WI...none. 
&& 


$$ 


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