Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 200532

Area Forecast Discussion
National Weather Service Aberdeen SD
1232 AM CDT Sun Aug 20 2017

Issued at 942 PM CDT Sat Aug 19 2017

The forecast tonight is still calling for (elevated) post-frontal
scattered showers and thunderstorms to develop/move into the cwa
basically after 06z, with convection chances persisting right on
into Sunday. Right now, the front has cleared KMBG, but is still
back west of KPIR, moving rather slowly east and south. A few
CAMs maintaining some higher-end simulated reflectivity
suggesting that there could be one or two stronger updrafts
embedded within the weak to moderate showers/storms that develop
overnight. Only minor adjustments made to the pops/qpf/weather
grids overnight. No other changes planned at this time.

UPDATE Issued at 633 PM CDT Sat Aug 19 2017

See below for an aviation forecast discussion for the 00Z TAFs.


.SHORT TERM...(This Evening through Sunday Afternoon)
Issued at 333 PM CDT Sat Aug 19 2017

Upper level low pressure trough axis off to our northwest will
continue to slide east across the northern part of our region
through Sunday afternoon. At the surface, a cold front/trough axis
across western South Dakota late this afternoon will push east
through the night bringing winds around to the northeast. Surface
high pressure will then build in and be over the eastern dakotas by
Sunday evening. The issue tonight will be the chances of
showers/storms. Most of the hi-res models show a fair amount of
echoes with the lift with this system with not much qpf. This
makes sense with fairly dry low levels through Sunday. With some
mid level instability available tonight and Sunday, expect accas
type/high based showers/storms to develop later tonight and remain
into Sunday. Therefore, have in some slight/chance pops for later
tonight and Sunday. Otherwise, it will be cooler with highs in
the upper 70s to the lower 80s for Sunday afternoon highs.

.LONG TERM...(Sunday Evening through Saturday)
Issued at 333 PM CDT Sat Aug 19 2017

Flat/fast flow aloft will start the period. However the mid level
pattern should start to buckle early next week as s/w energy digs
toward the Great Lakes. Meanwhile, a sfc front will remain splayed
out across the Central Plains from Colorado east to Iowa. This
frontal boundary will serve as a decent baroclinic zone through at
least the early part of the long term with daily MCS activity
expected. Sfc high pressure is likely to keep the highest amounts of
moisture/instability south of the ABR cwa and therefore leave most
of the forecast area dry. However, some late day and evening high
plains activity could make it into the western cwa. A subtle
boundary will pass through on Monday with perhaps some more
activity, but sfc high pressure following that front will likely dry
out the area for mid week. By late next week low pressure and llj
return to the western high plains as ridge aloft builds east into
the area. LLM/instability will again develop over the area, with a
renewed chc of rain. Temperatures through the period will probably
average out near to just slightly below normal.


.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1230 AM CDT Sun Aug 20 2017

Overall, prevailing flying weather should be VFR over the next 24
hours. High based showers will move across the area, and there may
be a few areas of thunder but generally too low a coverage to
include in TAFs.




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