Area forecast discussion...updated
National Weather Service Aberdeen South Dakota
1228 am CDT Tuesday may 21 2013
Update...
see updated aviation discussion below.
&&
Previous discussion...
short term...today through Tuesday
axis of showers has shifted into the eastern County Warning Area this
afternoon...with a break for counties west of Aberdeen. This break
will be short lived as radars upstream in North Dakota are quite
active...with widespread light/moderate rainfall. Hrrr and RUC
guidance pivots this moisture back over the County Warning Area this evening and
persists well into Tuesday. Most of the area has been able to
handle the moisture thus far...with a few spots reporting rising
water in ditches/creeks but not much impact otherwise. Sref
probabilities for greater then a quarter inch are highest across
our northern Missouri River counties...an area that has not
received much drought relief this Spring...and thus think that area
can handle the additional 1/2 inch of rain. Soils farther south
and east may be less forgiving and will need to be monitored this
evening/overnight for water issues.
As the stacked low continues to drift east Tuesday...lift weakens
with some drier air entrainment resulting in lower probability for
precipitation and quantitative precipitation forecast. Temperatures this period will remain below
normal and change little thanks to cloud cover.
Long term...Tuesday night through Monday
as the period opens...a decaying upper low circulation over the
region will be slowly drifting southeast out of the area.
Continued wrap-around moisture combined with some weak trowalesque
forcing/lift will keep probability of precipitation/rain showers mention going Tuesday
night into Wednesday as this low pulls away from the region.
Wednesday night through Thursday night should be dry forecast
periods while a transient high-amplitude longwave high pressure
ridge works through the region.
By Friday...low level return flow is in full swing and probability of precipitation for
showers and thunderstorms make their return to the forecast as middle
and upper level flow takes on a rather prolonged period of southwesterly
flow...that is currently prognosticated by the GFS and European model (ecmwf) to last
right into Monday.
The coolest temperatures during the period look to be Tuesday night and
Wednesday before the warming trend ensues. By the
weekend...temperatures should be much closer to climatology normal.
&&
Aviation...
06z tafs for the kabr...Katy...kpir and kmbg terminals
An area of rain will continue to spin over much of central and
northeastern South Dakota overnight and through the day Tuesday.
Ceilings and visibilities will vary between VFR and MVFR levels with the
rainfall. Breezy northerly winds of 20 to 30 miles per hour will affect kpir
and kmbg.
&&
Abr watches/warnings/advisories...
South Dakota...none.
Minnesota...none.
&&
$$
Update...wise
short term...Connelly
long term...dorn
aviation...wise
Weather.Gov/Aberdeen
