948 
fxus63 ksgf 072121 
afdsgf 


Area forecast discussion 
National Weather Service Springfield MO 
321 PM CST Wednesday Jan 7 2009 


Discussion... 


A large scale pattern shift is the main story for the next seven 
days. Although we will remain in a northwest flow aloft for the 
entire period...amplitude will be on the increase. We will 
continue to see a steady stream of short wave energy traverse the 
northwest flow across the Dakotas and Great Lakes. This regime 
will favor a cold front pushing through at least every few 
days...if not more frequently. With low level moisture lacking and 
the bulk of the energy remaining to our northeast...not expecting 
much in the way of precipitation. Overall...the best chances look 
to be across central Missouri. 


Tonight...an upper level jet streak coupled with short wave energy 
will pass through the region. There will also be some low level 
forcing present in the form of a weak cold front. Not much in the 
way of low level moisture to work with...so not too excited about 
precipitation chances. Best chances will be up across central 
Missouri where better overall lift is anticipated. Therefore think 
scattered flurries and perhaps some light snow will be the rule. 


Thursday...weak surface high pressure will settle across the 
Ozarks. A dry day is therefore in store with perhaps a few middle 
and high clouds. Winds also look to be light. Went on the cooler 
side of guidance...close to met numbers. 


Thursday night and Friday...strong warm advection will commence as 
an upper level trough digs southeast across the northern High 
Plains. Temperatures Thursday night may steady off or slowly rise 
late. 850 mb temperatures on Friday will approach double digits 
celsius along and south of the Interstate. This will translate to 
high temperatures in the 50s. May even see some low 60s across far 
southwest Missouri. There are two flies in the ointment for highs 
on Friday. The first will be increasing low level moisture and 
strong pressure advection which could lead to some stratus. The 
second will be a strong cold front which should be approaching 
southeast Kansas and west central Missouri by late afternoon. Kept 
probability of precipitation below 20 percent for now thinking moisture return will 
initially be lacking. 


Friday night into Saturday...that strong cold front will sweep 
through the region as that upper level trough digs southeast. 
Friday night will likely be the best shot at precipitation over 
the next seven days. Best chances look to be along and south of 
the Interstate with the better moisture. The precipitation should 
start off liquid...but a changeover to frozen is quite possible 
given what should be strong cold air advection. Any frozen 
precipitation will be quick to end as this system will be 
progressive. 


Early next week...strong positive height anomalies will develop 
off the British Columbia and Pacific northwest coast. This will 
favor the coldest air in the northern hemisphere setting up on 
this side of the North Pole and shifting back towards the Canadian 
prairies. This is an excellent setup for an Arctic intrusion into 
the northern tier and eventually Missouri Ozarks. Current 
time frame for the main Arctic surge is Tuesday or Wednesday. 
Until that time...clipper type systems will continue to push cold 
fronts through the region. Temperatures will therefore continue 
their roller coaster ride. Could see a shot or two of light 
precipitation if short wave energy can track close enough. 


Schaumann 


&& 


Aviation... 


VFR conditions will persist through Thursday morning with periodic 
bouts of middle and high clouds. The lowest ceilings will come late 
this afternoon and early this evening...averaging around 9000 feet 
above ground level. Brisk west winds early this afternoon will diminish by early 
this evening and then shift to the north by late evening. There 
is a brief window early this evening where low level wind shear is 
a concern. Looks too marginal to include at this time. 


Schaumann 


&& 


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


$$