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fxus63 kmpx 071708 
afdmpx 


Area forecast discussion 
National Weather Service Twin Cities/Chanhassen Minnesota 
1108 am CST Wednesday Jan 7 2009 


Update... 
quick update to trend more toward improving conditions this 
afternoon as discussed previously. 


&& 


Discussion... 
as suspected earlier it appears cloud redevelopment will be 
limited given coldness of airmass and lack of mixing into the 
better lapse rates above. Better cyclonic flow is also shifting 
east... so worked up quick update to include more optimistic 
conditions for the balance of the day. Some snow shower and flurry 
activity is still possible across east central and south central 
Minnesota through early afternoon... but otherwise allowing for 
skies to become partly to mostly sunny as is being seen in the 
upstream observation. 


&& 


Aviation.../12z taf issuance/ 
upper level low centered over dlh with backside wave diving from 
western Minnesota into southern Minnesota this morning. All of it pointing towards 
occasional flurries...with some embedded snow showers closer to 
the centers of these waves. Visbys and ceilings in the snow showers 
across western Minnesota and western WI may briefly reach IFR given trends with 
observation. MVFR ceilings will prevail by late morning through middle-afternoon 
areawide. After that point...suppression aloft and some low level 
dry air advection should begin to scattered ceilings out after that time. 
Eau will likely be the last to see improvement. During the night 
there may be some scattered broken MVFR ceilings as cyclonic flow lingers 
through 06z...but best moisture will mainly be east of the area. 
During the day Thursday just some increasing cirrus ahead of next wave 
which will bring a good chance for some mixed precipitation to msp late 
Thursday night/Friday morning. 


Surface winds will be from the northwest across Minnesota and west across western WI 
through tonight. Some gusts likely through the day with gradient 
and unidirectional flow within favorable lower-level lapse rates. 


&& 


Previous discussion... 
/issued 1013 am CST Wednesday Jan 7 2009/ 
made some quick yet subtle adjustments to the going forecast. Snow 
shower and flurry activity currently over the area is being 
supported in part by the shortwave currently moving through as 
seen in water vapor imagery. This wave will pass south and east of 
US by afternoon... but steep sub-500mb lapse rates will persist... 
which should help keep snow snow shower and flurry activity going. 
Best chance still looks to be over the eastern County warning forecast area... where 
deeper moisture will linger longer through the afternoon... 
although some chance will persist farther west with cyclonic 
boundary layer flow and some moisture lingering. Kept with the 
somewhat pessimistic cloud cover forecast... although that may 
need to be tweaked if current upstream observation over northern Minnesota 
persist... with a large hole apparent in the cloud cover. There 
should be some tendency for this to fill in... particularly over 
the central and eastern County warning forecast area as it sinks south... although the 
west may have a general trend toward fewer clouds as cyclonic flow 
vacates that area. The far southwest is close to the extensive 
zone of stratus extending back through Dakotas... although it too 
looks to slide a bit southwest through the day. Made some small 
downward tweaks to the temperatures to line up with current observation 
and latest guidance from the RUC and NAM MOS. 


&& 


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


$$ 


Trh/mtf/trh