313 
fxus63 ksgf 212335 
afdsgf 


Area forecast discussion 
National Weather Service Springfield MO 
535 PM CST Sat Nov 21 2009 


..update to aviation... 


Discussion... 


The main forecast focus was on early next week as this will be our 
next shot at precipitation. This will be the start of a large 
scale pattern change as the upper level flow becomes more 
amplified and northwesterly across the central United States. This 
will result in below normal temperatures for the middle to late week 
period. 


A rather flat and progressive upper level pattern will persist for 
the remainder of this weekend. We will see one weak short wave 
trough cross the region Sunday night...but moisture will be very 
limited. Could see a shower across southeast Missouri...but that 
would be about it. Stuck very close to mav/met blend for 
temperatures for the remainder of the weekend. 


The pattern will slowly become more amplified next week. Digging 
potential will increase throughout the week for any short wave 
energy originating from the Pacific northwest or western Canada. 
The first such wave will move into the northern and Central 
Plains from late Monday into Tuesday. We will see some increase in 
low level moisture ahead of this feature as low level winds 
increase out of the southeast and south. A cold front associated 
with this upper level energy will likely be the focus for 
precipitation chances. Current thinking is this front will pass 
through the Ozarks Monday night. Have raised probability of precipitation for this period 
into the high chance category. May see some lingering showers into 
Tuesday across central Missouri. 


Global models continue to advertise a second wave strongly digging 
in behind this initial wave around midweek. This wave will likely 
bring a stronger cold front across the area...with 850 mb 
temperatures prognosticated to dip into the -5 to -10 degree celsius 
range by both the 12z GFS and European model (ecmwf). Therefore cut temperatures 
starting around midweek. It is quite possible that we see our 
first widespread hard freeze across the region later next week. Am 
not seeing much if any precipitation threat later next week with 
the possible exception of central Missouri closer to the track of 
that second wave. 


Schaumann 




&& 


Aviation... 


For the 22/0000z ksgf/kjln/kbbg tafs...VFR ceilings are expected 
at times as a disturbance moves south and east of the area. 
An upper level disturbance will move west-east through MO late 
Sunday...but with limited moisture...VFR conditions are expected to 
continue. Dsa 




&& 


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


$$