864 
fxus63 kmpx 140011 
afdmpx 


Area forecast discussion 
National Weather Service Twin Cities/Chanhassen Minnesota 
611 PM CST Sat Mar 13 2010 


Update... 


Added aviation discussion for 00z tafs below... 


&& 


Discussion... 


Easterly...somewhat difluent...upper flow bringing a weak wave 
across the area tonight. Some light returns showing up on radar 
now. Some fog still in place over western Minnesota and this will continue 
to be the case overnight and may extend back west later. Will try 
to place the most emphasis on the west and southwest where there 
is remaining snow cover. Some weak upper flow will exist over the 
eastern Dakotas and western Minnesota Sunday into Monday...while another 
short wave tops the ridge out west. There is general agreement 
when looking at the mean of the ec...GFS...and Gem..that this wave 
will drop south over the area on Tuesday. Have added a small pop 
for this. Otherwise...mainly cloudy conditions continuing until the 
Tuesday wave pushes out of the area. Temperatures will be held down in 
the cloudy areas to readings similar to today...but holes in the 
clouds are bringing up temperatures into the lower 50s over central WI. 
Some low level drying is possible from the east by Monday when we 
will see a better chance of some high in the 50s. More widespread 
warming by Wednesday and Thursday ahead of the front and height 
falls along about Friday. 


Have continued the trend of some probability of precipitation for Friday and Saturday as 
low pressure develops in the plains behind the initial cold front. 
Chance of snow later Friday night and Saturday as northwest flow 
strengthens over the northern rockies and western Canada. 


&& 






Aviation.../00z taf issuance/ 


Wide range of conditions across the terminals this evening with 
IFR/LIFR continuing west with MVFR conds east. Abundant moisture 
remains over the area with ceilings/visibility still able to improve across 
far east central Minnesota and west central WI. However expect that ceilings will decrease 
during the middle/late evening over these areas with visibility decreasing 
as well. Overall expect kmsp/krnh/Keau fall to higher end IFR low 
end MVFR by late evening. Kaxn/krwf should see the low conditions 
continue this evening then fall to LIFR overnight. There is a bit 
tighter pressure gradient expected tonight so visibility should be 
slightly better than previous nights but some vlifr visibility is still 
possible. Some drizzle or light rain will be possible at kaxn 
towards daybreak as a weak upper disturbance moves from east to 
west. Dry low level air attempts to work in from the east Sunday 
morning and Sunday afternoon. Based on the improvement seen this 
afternoon things should improve further on Sunday for east central Minnesota 
and west central WI. Have scattered the clouds out for these areas 
early Sunday afternoon which could be a little optimistic timing wise. 
Improvement to MVFR is possible by late Sunday afternoon at kaxn 
and krwf. North to north-northeast winds will continue through 
the period. 


Kmsp...ceilings up to around 2 kft are expected to decrease back into 
the 1000 to 1500 feet range this evening. Main question will be how 
quickly this occurs...and may be a little pessimistic with 
bringing them back at 02z. Should hover on the IFR/MVFR threshold 
ceiling wise with visibility of 4 to 6 sm expected tonight. Drier air 
from the east should bring an improvement to ceilings early Sunday 
afternoon and VFR conditions should result. Will need to watch but 
feel fairly confident in this scenario given the improvement seen 
this afternoon under very moist conditions. North-northeast winds 
will continue with speeds dropping off to around 6 kts overnight 
then increasing slightly for Sunday. ..mdb.. 


&& 


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


$$ 


Jpr/mdb