948 
fxus63 klbf 071928 
afdlbf 


Area forecast discussion 
National Weather Service North Platte NE 
225 PM CDT sun Sep 7 2008 


Synopsis... 
hand analysis of the 18z surface data showed a front across from 
western Iowa...across Nebraska...to a low in northeast Colorado. 
Higher 55-60f dewpoints were over much of northern Kansas to the 
south of the front. High pressure was the dominant feature from west 
central British Columbia...across southern Alberta and southwest 
Saskatchewan...into northern Montana with a ridge extension into 
South Dakota and north central Nebraska. 
&& 


Short term...tonight through Monday night. 
The front across Nebraska is likely to slip southward a little 
farther and become nearly stationary. Upglide along the front is 
expected to generate widespread rain over much of central and 
western Nebraska. The slope of the 300k and 305k is steepest and the 
moisture transport vectors are strongest along and north of i80... 
but instability is along and south of i80. So...the greatest rain 
accumulation should be over central through northwest Nebraska and 
the best chance of thunderstorms will be in the southwest. Rain will 
taper off late Monday morning to early afternoon as the Canadian air 
mass pushes the front out of the area. 


Extended...Tuesday through Sunday. 
As early as Tuesday morning...return flow from the Texas Gulf 
Coast begins to bring low level moisture to the southern High 
Plains. In turn the moisture slowly makes its way northward through 
Tuesday night and into Wednesday. Then a front coming in from the 
northwest will encounter the resulting Theta-E ridge and create the 
lift needed for thunderstorms Wednesday and Wednesday night. The 
uncertainty regarding the sub-tropical moisture fields precludes our 
going too strong on the probabilities. After Thursday...another 
front is expected to swing through Saturday. This may bring another 
shot at precipitation. 
&& 


Aviation... 
favorable lift over a front across southern Nebraska has kept 
6-9kft ceilings across sandhills and northern Nebraska...while ceilings are 
trying to break up father south. System dropping out of northern 
rockies into plains overnight and will bring widespread 
precipitation to western and north central Nebraska overnight 
through at least late morning on Monday. Ceilings and visibility both look to 
be affected by this system with widespread MVFR likely due to rain 
shower and ceiling restrictions...however also expect temporal and 
spatial IFR restrictions as well. Some thunderstorm activity may 
also be present south of Interstate 80 where some cells may contain 
hail at least aloft. Some clearing to VFR looks possible with 
subsidence behind the retreating system by Monday afternoon. 
&& 


Lbf watches/warnings/advisories...none. 
&& 


$$ 
Springer/13