951 
fxus63 keax 182019 
afdeax 


Area forecast discussion 
National Weather Service Kansas City/Pleasant Hill MO 
319 PM CDT Friday Jul 18 2008 


Discussion... 


Mesoscale convective vortex has shifted slowly east into extreme northestern Kansas with tropical plume 
extending from scntrl Kansas into much of the County Warning Area. The extensive cloud 
cover has limited heating with instability quite weak. 
Nevertheless...scattered showers and isolated thunderstorms have 
developed across much of the County Warning Area in advance of the mesoscale convective vortex as precipitation 
water values were a little above two inches. Models suggest that mesoscale convective vortex will 
rotate acr northern MO tonight with tropical inflow band to persist much of 
the night from portions of the west-central MO to north central MO. Have confined 
the highest probability of precipitation within in this region. Mcvs tend to go through 
diurnal increases in intensity at night with bands of moderate 
tolocally heavy rainfall possible. 


Moist 700 mb inflow band may still produce scattered showers mainly over the 
eastern County Warning Area Saturday morning but will gradually diminish in the afternoon has 
700 mb moist shifts east. 


Otherwise...old outflow boundary was from near stj to irk but 
convergence is quite weak. True frontal boundary was located from northern 
Nebraska to near Iowa with little movement seen. This boundary should have little or 
no impact on precipitation development tonight. 


Cloud cover will hold temperatures to near seasonal norms on 
Saturday. However...middle cloud cover will thin Saturday night with low 
level flow veering on Sunday. This will result...in very warm 
temperatures as 800 mb temperatures rise to between 22-24c. 


Another shortwave moving through the northern plains may drive a front to near 
the MO bdr Sunday night. Strong cap may preclude development along the 
front...but will hold a slight chance of convection acr northern MO. 


Db 


Medium range (monday through friday)... 


For next work week do not expect much if any respite from the hot 
and humid conditions that will move in this weekend. The prevailing 
trend in the Middle Range models center around a ridge moving in and 
taking control of the weather across the Rocky Mountains. The 
consensus is that the ridge axis stays anchored to our west as some 
form of trough develops across the eastern Seaboard. 
However...discrepancies in the solutions become apparent when 
examining the east Continental U.S. Trough. European model (ecmwf)/Canadian/UKMET all advertise 
a unseasonably strong low developing at the core of the east Continental U.S. 
Trough next week...while the GFS holds on as the outsider shearing 
the trough apart much faster. Either way...the picture is still 
further clouded by the numerous shortwaves that are prognosticated to be 
beating on the western Continental U.S. Ridge before advecting east into the 
trough. For the Central Plains these issues in the models will 
mostly play out in how they affect the position of a possible 
backdoor cold front that will be draped across either the northern 
or Central Plains next week...and how then this front effects 
temperatures and precipitation chances. 


With so many competing factors weighting on the forecast for next 
week...have opted to make only minimal changes to the going forecast 
for next week. Moderated some temperatures a little for next week as 
a nod to the prevailing majority solution represented by the European model (ecmwf) 
where the front makes inroads into Missouri...but also still kept 
the moderated highs well above normal as a hedge towards the GFS. 
Kept precipitation chances focused across north central and northeast 
Missouri...but kept them in the slight chance range given 
uncertainty in the pattern. 


Cutter 


&& 


Aviation... 


A tropical plume continues to stream NE of the terminals ahead of an 
mesoscale convective vortex over eastern Kansas. Extensive cloud cover will limit instability through 
Saturday morning with mainly VFR occasional showers through the period. 
Brief periods of MVFR ceilings and fog are possible around daybreak. 


Db 


&& 


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