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fxus63 keax 041705 
afdeax 


Area forecast discussion 
National Weather Service Kansas City/Pleasant Hill MO 
1105 am CST Thursday Dec 4 2008 


..updated aviation discussion... 


Discussion... 


The entire forecast can be stated eloquently in one word: brrrrrrrr. 
Positive pna pattern will continue to dominate through the period 
with western ridging and a deep eastern trough maintaining a 
seasonably strong polar jet to our south and west. This will keep 
temperatures well below normal for the foreseeable future...and 
maintain an active wave train from western Canada into the Great 
Lakes. 


While possible that the tail end of these clippers could bring some 
very light snow/flurries to the NE County Warning Area (one such event early 
saturday)...dry weather will generally dominate through the weekend. 
Going forecast essentially requires no change...with northern County Warning Area already 
adjusted for effects due to snow cover. 


With respect to significant changes in the forecast (none too 
pleasant)...one must note the large Omega block that has developed 
from central Asia to the Aleutian chain. The overall pattern has 
retrograded slowly westward over the past 10-14 days...putting The 
Squeeze on a highly amplified ridge situated along 160e. This 
actually has major implications on the weather over the lower 48 
next week as most of the medium range solutions close off the northern 
portion of this ridge and crest it across northern Alaska into the northwest 
Canadian territories. This scenario would dislodge the polar vortex 
and the Arctic jet southward...bringing true cross-polar flow into 
north central US... still a lot of details to be resolved over the 
coming week...but a near 100 percent certainly of below normal 
temperatures through much of the next 7 to 10 days with a fair 
potential for much below normal temperatures. At the leading edge 
of this secondary surge...there is the potential for a major winter 
storm developing Monday night/Tuesday that will need to be monitored 
closely. 


Bookbinder 


&& 


Aviation... 


VFR conditions expected through the taf period...with only scattered-broken 
middle and hi level ceilings...mainly this afternoon. A secondary cold front will 
move through this afternoon with an increase in wind speeds. Surface high 
will move into western MO with light and variable winds tonight. Winds 
switch to the SW on Friday in advance of the next cold front. 


Db 


&& 


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