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Area forecast discussion 
National Weather Service Norman OK 
257 am CST Friday Nov 21 2008 


Discussion... 
effects from the system now moving across the northern rockies 
should remain to our north. Surface high will be over the area this 
morning and will move off to the east by this evening. Despite return 
of S winds... cold start and slow modification of Canadian air 
mass will lead to another chilly day. 


Will keep low probability of precipitation as they were for sun and Sun night ahead of 
full-latitude trough and surface cold front. Post frontal air mass 
will be more of modified Pacific origin Sun night into Monday. 


Reasonable agreement that the western North American ridge will 
set up farther east - over or near the High Plains - by middle of 
next week. With the ridge axis overhead or nearly so... there 
should be a gradual but decent warmup by next Wednesday. 


Beyond Wednesday there is general agreement that an upper low will 
close off over or near the NE states and a trough will move into 
the western states... shifting the upper ridge axis to our east over 
the MS valley. GFS is much faster than the European model (ecmwf) in bringing a 
lead negative-tilt trough into the plains on Thanksgiving. Operational 
GFS has timing support from the gefs mean and quite a few 
individual members. Overall blocky nature of the flow downstream 
would argue for the slower European model (ecmwf)... but both the GFS and the European model (ecmwf) 
are on the same Page with a fairly robust kicker trough reaching 
the West Coast by Thursday. Whether the faster GFS or the slower 
European model (ecmwf) pans out... both are progging decent low-level warm 
advection and return flow of Gulf moisture into the S plains by 
Thursday. Both have surface dewpoints of 60+ crossing the Red River by 
Thanksgiving evening... along with some healthy precipitation amounts. On 
this basis we will introduce low probability of precipitation as early as Wednesday night... and 
expand and increase the probability of precipitation on Thanksgiving along with a mention 
of T-storms. Min temperatures are trended upward with return flow and 
increasing dewpoints underway by Thursday morning. May well have lows 
in the 50s or even 60s by end of week. Highs will not be raised as 
much due to possible effects of clouds/precipitation keeping diurnal 
ranges down. 


&& 


Preliminary point temps/pops... 
Oklahoma City OK 44 26 53 36 / 0 0 0 0 
Hobart OK 47 30 54 37 / 0 0 0 0 
Wichita Falls Texas 50 31 58 41 / 0 0 0 0 
gage OK 47 24 57 31 / 0 0 0 0 
Ponca City OK 42 28 52 37 / 0 0 0 0 
Durant OK 51 27 52 41 / 0 0 0 10 


&& 


Oun watches/warnings/advisories... 
OK...none. 
Texas...none. 
&& 


$$ 


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