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fxus63 keax 212146 
afdeax 


Area forecast discussion 
National Weather Service Kansas City/Pleasant Hill MO 
346 PM CST Sat Nov 21 2009 


Discussion... 


A weak warm front was located across the southern County Warning Area with low level 
moisture locally pooled near the boundary. The boundary will shift 
quickly north and dissipate. As per forecast soundings suggest...the 
moisture is quite shallow. This appears reasonable given the lower 
dewpoints well to our south...in areas where deeper mixing has 
occurred. Given intervals of cloud cover tonight and stronger southeast 
winds...do not expect widespread dense fog tonight. Given the mixy 
nature of the soundings just above the surface...stratus would likely be 
the result if moisture was deep enough. At the current time...moist 
layer appears insufficient for stratus. The only exception may be 
across the northern grids tonight where low level moisture is a little deeper. 


Will introduce patchy fog for the northern grids tonight and let the 
evening shift make any refinements based on current trends. 


Moisture imagery depicts a shortwave moving into the southern and central 
rockies. Models suggest that this shortwave will eject east-northeast into the 
County Warning Area Sun night. Moist is limited with forcing rather weak. Cannot 
rule out a few sprinkles...but will not introduce at this time. 


Otherwise...main concern is late Monday afternoon and Monday night when a strong 
upper level low moves into the plains. The models have a general 
consensus in moving the upper level low near the MO/Iowa bdr Monday night and 
Tuesday with a strong wave moving around the southern periphery of the upper level 
low. Much of the County Warning Area is in the favorable quadrant of a 90kt 300 mb speed maximum 
Monday night with a modest pvu maximum rotating through Missouri. Given the 
low static stability and modest qg forcing...have increased probability of precipitation for 
late Monday afternoon and Monday night. In addition...cannot rule out an isolated 
thunderstorm given the potential for MUCAPES around 100 j/kg. 


Db 


Medium range (tuesday through saturday)... 


Overall decent agreement among ensemble guidance with respect to to the upper 
air pattern through the upcoming work week. By the beginning of the 
week...short wave trough is expected dive across the central Continental U.S. 
Bringing increasing precipitation chances to the area. Differences 
in the exact location and timing of this feature is evident among 
various solutions...however the general idea is certainly 
consistent. By Tuesday...upper low will slide across the Central 
Plains and Midwest with location and timing by this time frame key 
in determining where precipitation is most likely and when its expected to 
push east of the County Warning Area. Will keep highest rain chances across the 
northern half of the County Warning Area for Tuesday...sliding activity east with 
time through Tuesday night and Wednesday. 


Upper trough axis appears to be fairly progressive with additional 
short wave energy quick on its heels. Lingering precipitation/cloud cover 
may be evident through midweek as secondary short wave trough dives 
south on the backside of departing system. This will also serve to 
bring some slightly cooler air southward into the midwestern states 
by Wednesday and Thursday. Upper short wave ridging will then 
translate atop the region for the latter part of the week and into 
the week bringing warmer temperatures. 


Deroche 




&& 


Aviation... 


For the 18z tafs...a VFR stratocu cloud deck prevailed acr the terminals 
early this afternoon. However...a MVFR stratus deck was noted in southeastern 
Kansas...ahead of a weak warm front. It is difficult to determine the eastern 
edge of the cloud deck due to the higher stratocu deck. Both the GFS 
and NAM suggest that the MVFR cloud deck may clip the terminals late 
this afternoon. Confidence is not high. Regardless...the MVFR cloud deck 
will shift north tonight and be replaced with a MVFR stratocu/ac scattered- 
broken deck. May see periods of MVFR fog late tonight at the 
terminals...but given cloud cover and modest winds...IFR fog is not 
expected. Otherwise...any MVFR will burn off rapidly after sunrise with 
VFR conditions for Sun morning. 


Db 


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






&& 


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


$$