Scientific Forecaster Discussion

NWS Discussion
			
				

Area forecast discussion...updated 
National Weather Service Aberdeen South Dakota 
626 PM CDT Thursday may 23 2013 


Update... 
see updated aviation discussion below. 




&& 
Previous discussion... 
short term...tonight through Saturday night 
a somewhat active pattern for the short range. Models are in 
general agreement that a middle level western Continental U.S. Trough will develop 
during the period...with return flow quickly bringing 
moisture/instability back into the western High Plains. It appears 
this area will remain the focus for convective 
initiation/development through much of the period. With an mesoscale convective system or 
two beginning out west and riding the low level jet east overnight. Deep 
layer bulk shear will be sufficient enough to get some decent 
storms going...especially the western High Plains where 
moisture/instability will be more prolific. As for 
temperatures...they should generally be near or slightly cooler 
than normal across the region. Winds will be gusty from the south 
on Friday...however for now they appear to remain near or just 
under Wind Advisory criteria and thus will fore-go any headline 
for the time being. 




Long term...Sunday through Thursday 
models agree fairly well in the extended with the evolution of 
the long wave flow pattern across the Continental U.S.. weak to moderate 
ridging will persist across the southeast portion of the US...with 
a trough over the southwest. Southerly flow ahead of the upper 
level trough and surface low pressure should be the focus 
mechanism for a prolonged period of showers and thunderstorms for 
the northern plains and upper Mississippi Valley. While there is 
at least a chance for storms each day in the extended...believe 
there well be periods of dry conditions mixed in. Timing dry 
periods are rather problematic as the GFS/European model (ecmwf) show several short 
waves tracking across the region at various times. Thus will stick 
with allblend probability of precipitation for now and fine tune in the future. 




&& 


Aviation... 
00z tafs for the kabr...Katy...kpir and kmbg terminals 


VFR conditions will prevail tonight and through the day Friday. 
South to southeasterly winds will increase into the 20 to 35 miles per hour 
range by late morning on Friday. Scattered showers...and a 
thunderstorm or two...are possible during the afternoon hours on 
Friday as well. 




&& 


Abr watches/warnings/advisories... 
South Dakota...none. 
Minnesota...none. 
&& 


$$ 
Short term...tdk 
long term...South Dakota 
aviation...Parkin 


Weather.Gov/Aberdeen