Area forecast discussion...updated
National Weather Service Aberdeen South Dakota
1234 am CDT Tuesday Jun 18 2013
Update...
see updated aviation discussion below.
&&
Previous discussion...
short term...tonight through Wednesday night
a well mixed...weakly unstable atmosphere resides overhead
today...with a few hundred j/kg cape. A few storms may pop over
far northeast South Dakota/western Minnesota...closest to the
upper low circulation. With loss of heating...storms will
dissipate. Stable/cool conditions expected again overnight.
High pressure north of the area will provide for stable conditions
on Tuesday with and upper ridge building in from the west. Return
flow begins to develop late in the day...with a fetch linking the
region to Gulf of Mexico moisture by early Wednesday. This brings
thunderstorms back into the forecast for Wednesday...though much
depends on timing. The question is whether increased low level
moisture will help destabilize the atmosphere ahead an
elevated mixed layer which is also going to push in from the
southwest. Will continue to advertise chance probability of precipitation as model mixed
layer dewpoints push into the low 60s...however if timing is off
we may cap before surface based convection develops. If all GOES
to plan...will be looking at about 2000 j/kg cape under a fairly
weak shear profile.
A second bout of storm activity is possible Tuesday am as a 30 to
40 knots low level jet forms over the Dakotas/Nebraska...and warming
in the middle levels leads to elevated instability.
Long term...Thursday through Monday
an active pattern remains in place for the extended. The period
opens with an exiting upper level ridge. At the surface a trough will
begin to move off The Rockies and slowly push east across the
plains through the weekend. Ahead of the trough it looks like there
will be good moisture availability with 700 mb temperatures only around 12 to
13 degrees...a very favorable set up for thunderstorms. By Friday
warmer temperatures aloft advect in from the south helping to cap off the
atmosphere. Though precipitation chances persist in the afternoon and
evening as a shortwave moves across the northern County Warning Area where temperatures
aloft will still be relatively cool.
The weekend is still pretty far out in the forecast world to Pin
Point any particular area for convection though potential
continues for thunderstorms. Stuck close to allblend again with
mainly chance probability of precipitation through Sunday.
Temperatures may need to be bumped up on Friday with anticipated
warm air advection. Currently have middle to upper 80s in the forecast. Reaching the
lower 90s will not be outside the realm of probability.
Otherwise temperatures will hover in the lower to middle 80s during the
period.
&&
Aviation...
06z tafs for the kabr...Katy...kpir and kmbg terminals
Outside of isolated showers/storms tonight it should be VFR through
Tuesday.
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Abr watches/warnings/advisories...
South Dakota...none.
Minnesota...none.
&&
$$
Short term...Connelly
long term...wise
aviation...Parkin
Weather.Gov/Aberdeen
