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fxus63 keax 091143 
afdeax 


Area forecast discussion 
National Weather Service Kansas City/Pleasant Hill MO 
542 am CST Friday 
Jan 9 2009 


..updated aviation discussion... 


Discussion... 
/318 am CST Friday Jan 9 2009/ 


Busy forecast period as several short wave troughs of interest 
expected to traverse the area in the coming week. 


Early this morning...elongated pressure falls from eastern Nebraska 
and across the High Plains have taken shape with a distinct surface low 
noted near Norfolk NE as of 3am. This has resulted in southerly low level 
flow across eastern Kansas and western/central Missouri leading to 
steady or slowly rising temperatures overnight. Most locations look to start 
out above the freezing mark by sunrise which will be a precursor to a 
decent warm up by this afternoon. Southwesterly 850 mb flow will likely 
usher in 850 mb temperatures of 8-11c across areas along and south of the 
Missouri River by the afternoon hours with readings of 6-8 degrees 
north. Have hedged temperatures up a bit to account but the upward trend 
will ultimately be contingent on the arrival of the next cold front 
to push into the area during the afternoon hours. 


Cold front should be through all counties by this evening with cold air advection to 
follow. Appears atmospheric moisture profile will not be sufficient 
for precipitation production until the frontal boundary reaches 
portions of central Missouri. Have therefore limited chance probability of precipitation to the 
far southeastern counties which should initially begin as rain. 120+ 
knots h25 jet organizes across southern and central Missouri by tonight 
placing the County Warning Area within favorable larger scale lift of left exit 
region. Modest middle level frontogenesis along with increasing q-vector 
convergence looks to establish by later this evening into the 
overnight hours. Have raised probability of precipitation...mainly across northeastern 
counties where the best combination of forcing looks to align. 
Overall...not expected a big snow maker out of this system but could 
end up with a quick half inch or so across portions of north central 
Missouri. 


Cold air advection will be in place for the majority of the day Saturday and 
expecting most areas to remain below the freezing mark throughout. 
However...this should be fairly short lived as a downsloping 
component establishes by Sunday with a return to above normal temperatures. 


Next concern arrives by Monday with the approach of the next short 
wave trough within overall northwest flow regime. Previous forecast 
seemed to capture this feature well and only cosmetic changes made to 
going grids. No changes made beyond day 4. 


Deroche/dnb 


&& 


Aviation... 


VFR conditions ahead of boundary should rapidly give way to MVFR 
stratus toward 22z as a cold front nears. MVFR ceilings will gradually lower 
by 02z as patches of light snow or flurries move through the 
terminals between 01z-05z. All precipitation should end between 03z-05z. 
Brief burst of visibilities below 3 miles are possible during the 
precipitation event...but will likely be too brief to include in the 
terminals. MVFR ceilings will continue through the night as cold air advection stratus 
rotates cyclonically around the departing low pressure system. 
Otherwise...the passage of the front will also cause the winds which 
started the period from the southwest to turn to north and likely 
become gusty behind the front from the north. 


Dnb 


&& 


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