Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Aberdeen South Dakota
623 am CDT sun Mar 16 2014
aviation discussion has been updated.
short term...through Tuesday
High pressure moving across the western lakes region extends into
the northeast County Warning Area...allowing for ideal radiational conditions.
Already seeing southerly flow develop West River however...so
anticipating most of the area will be back to above normal
temperatures today as h925 readings top out between +9 and -1c.
Only caveat that will limit highs is the wind direction is almost
due south and thus not at peak efficiency. Same GOES for Monday as
850 mb temperatures jump to +12 to +6c...a Standard deviation above
Not real thrilled with precipitation chances across the northern
tier of the County Warning Area with any of the weak waves/surges in warm
advection aloft moving north of the area...mainly thanks to
warm/dry low level conditions and generally weak forcing aloft.
Most of the focus is on the shortwave moving across the County Warning Area
Monday night/Tuesday. Models are still having consistency
issues. The general trend from deterministic guidance is a surface
low will develop over South Dakota...so we will be in the warm
sector Monday night into Tuesday...and as such will initially see
rain. The GFS does have upwards of 200 j/kg cape West River...so a
rumble of thunder or two cant be ruled out. Forcing increases
significantly on Tuesday...particularly on the backside of the
system. GFS Omega values top out around 40 microbars...around the
time profiles transition to snow. Thus...looks like there remains
a good chance that this system will produce a band of heavy
snow over the County Warning Area...though locations vary between models.
Long term...Tuesday night through Saturday
The middle level pattern Delaware-amplifies somewhat over the central and
western Continental U.S. During the period. A decent system will be exiting the
region early in the period. However strong flow aloft will lead to
quick moving and weaker systems for the remainder of the forecast.
Confidence in the forecast details is low...and therefore its
prudent to stick with the model blend/super blend given model
timing/strength differences. Overall temperatures should average
out near to below normal.
12z tafs for the kabr...Katy...kpir and kmbg terminals
VFR conditions are expected through today at kabr/Katy...along
with gusty south winds. Meanwhile it is a bit unclear as to
whether IFR/MVFR ceilings will spread into kmbg/kpir this morning
before possibly mixing out later in the morning or afternoon. For
now am carrying in a several hour mention at the beginning of the
taf period. Due to uncertainty will not carry IFR/MVFR ceilings past