Afternoon Update, Saturday 23, 2011
Forecast discussion to highlight two continuing precipitation threats over central to north central Oklahoma as previously outlined in the morning discussion.
Initial precipitation threat is associated with a developing low level jet and what appears to be sufficient moisture return early Sunday morning lifting back over a surface boundary currently firing a few intense cells south of the Red River. Model output convergence has settled on a early morning time around 9-12 UTC for precipitation nearest to Lamont, with confidence higher than previous day's set-up that resulted in a similar elevated broken convection. Precipitation should clear the region after 15 UTC.
Chances for precipitation associated with a developing surface front and coupled passing of upper level wave increase for parts of Oklahoma throughout the early evening on Sunday. However, models are trending to place this developing line continuously to the south and east of preferential campaign facilities - initiating before 00 UTC, which is one trend in good agreement with GFS, WRF and NAM solutions.
At present, the strength of this developing line initiating in later afternoon Sunday is also in solid disagreement across most forecast models (NAM, GFS, WRF); Under a current preferred solution that might also favor campaign facility precipitation (NAM), the convective line and associated precip will develop farther east and in souther parts of Oklahoma, with weaker overall intensity than other solutions (highly vigorous in GFS). This weaker solution is subsequently favorable for a similar development of precipitation over the campaign facilities associated with another overnight low level jet moisture return flow. The precipitation at this time should also be aided by additional upper level support with the eventual passage of the upper level trough.
