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fxus63 keax 161724 
afdeax 


Area forecast discussion 
National Weather Service Kansas City/Pleasant Hill MO 
1224 PM CDT Tuesday Mar 16 2010 


..updated aviation discussion... 


Discussion... 
/issued 323 am CDT Tuesday Mar 16 2010/ 
the unassuming weather of the next few days belies the forecast 
difficulties that will prevail across the region as we draw near the 
end of the work week...which might see some rain with embedded 
thunderstorms Friday give way to some snow by Saturday. 


In the short term...shortwaves of importance for our forecast over 
the next two days can be found moving east through Texas...and 
south through the Dakotas and Minnesota. Southern stream wave will 
have little noticeable effect on the forecast in the coming days 
other than to help drag the northern stream wave south through the 
lower Missouri River valley. As the northern wave drops south model 
consensus is that there should be some nominal lift associated with 
the system. Problem then become diagnosing available moisture for the 
system to work with...and cursory indications from 00z/16 soundings 
point at moisture being a bit on the sparse side. Still...lift from 
qg forcing as the system settles south through Missouri later tonight 
looks sufficient to warrant some low end chance probability of precipitation for showers. 
Otherwise...look for the cold air aloft...and at the surface...along 
with cloud cover accompanying this wave...to keep temperatures a 
little below normal through Wednesday. 


Looking at the tail end of the work week...with the passage of the 
northern shortwave Wednesday a shortwave ridge will move in to 
prevail for a brief period across the Central Plains. With plenty of 
sunshine...and a return of southerly winds...temperatures ranging 
through the 60s still looks like a good bet for Thursday. However... 
as is typical in early Spring...the cool air is not too far 
north...and is simply waiting for a reason to scoot south. Of 
course...the reason the cool air is waiting for will begin to nose 
into the plains states Friday...in the form of a progressive trough 
which will push a cold front through our forecast region Friday 
afternoon and night. Middle-Range models continue to have issues with 
pinning down how progressive the trough will be...and where the 
associated surface low will track...but the majority of the 00z/16 
runs point towards some form of low moving through southern Missouri. 
This would place our forecast region on the cold side of the system 
by early Saturday morning. Given the consistency of the precipitation 
signal with the trough in the past several model runs...have gone 
ahead and upped probability of precipitation for Friday by spreading the likely probability of precipitation across 
the entire region Friday night. Have also gotten a little more 
aggressive with the mention of snow Saturday. However...confidence in 
any specific aspect of the Friday/Saturday forecast is on the low 
side due to the inherent difficulties in pinning down the speed of 
the trough...and the specifics in the thermal profile. 


Cutter 




&& 


Aviation... 


The persistent stratus deck will continue to blanket the taf sites 
with overcast skies for the remainder of the day. Conditions should 
lift to MVFR by this afternoon. Overcast conditions will remain 
through the overnight and morning hours as a shortwave from the 
northern plains pushes southward and clips the region late tonight 
and early Wednesday morning. This will drop ceilings back down to IFR 
conditions. The greatest chances for any measureable precipitation are 
generally to the east of the taf sites...however a brief rain shower 
early Wednesday morning is not out of the question. 


Ach 


&& 


Eax watches/warnings/advisories... 
MO...none. 
Kansas...none. 
&& 


$$