Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 272335 AAA

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
635 PM CDT Sun May 27 2018

Issued at 633 PM CDT Sun May 27 2018

See updated aviation discussion below.


.SHORT TERM...(This Evening through Monday)
Issued at 246 PM CDT Sun May 27 2018

The next 24 hours look to get a bit more active across the region.
For tonight, sfc front extending from southeast North Dakota, south
to around KPIR is expected to shift a bit more southeast overnight,
and then basically fall apart on Monday as emphasis shifts back to
the west. S/W lifting out of western CONUS trof will interact with
frontal boundary later tonight, producing showers/storms. CAM
solutions tend to highlight mainly western and central parts of
South Dakota for MCS activity tonight. Lower resolution models do
allow more storms to develop over eastern CWA in the vicinity of sfc
front, but warmer temperatures aloft and capping may keep a lid on
or at least limit activity. For Monday there remains some mixed
messages. Deep layer shear is pretty weak, but low level shear looks
decent. MLCAPE looks to favor the low/moderate intensity category by
afternoon. Increasing pops from west to east looks okay for Monday
as more energy exits the western trof. Temperatures overnight will
be mild, but should be a little cooler on Monday given cooling aloft
and some easterly component to the wind.

.LONG TERM...(Monday Night through Sunday)
Issued at 246 PM CDT Sun May 27 2018

An unsettled pattern persists for the week. Multiple shortwaves
attributed to a low pressure system over Montana, later moving
through the Dakotas, will result in thunderstorm chances Tuesday
morning through Wednesday morning.  Though bulk shear and mid-level
lapse rates are not real impressive, isolated severe thunderstorms
aided by a weak low-level jet, are possible Tuesday morning with
NAM/GFS MUCAPE values over 2000 J/kg in northeast SD.  Ample
moisture also exists with boundary layer dewpoints in the 60s
Tuesday. Further thunderstorm chances exist Friday night into
Saturday off warm and cold frontal boundaries as low pressure in
eastern Wyoming/ Montana skirts off into Saskatchewan. Confidence
this far out is low as there is a range in outcomes between
deterministic guidance for that time period.

Temperatures will be a bit cooler than recent days, but still remain
above average overall before becoming hot again Thursday and Friday,
with 850mb temperatures on average at 1 to possibly 2 standard
deviations above climo. A cold front moves through Saturday
resulting in temperatures only a bit above average to finish the
period, but again, confidence on timing is low due to the range of
deterministic outcomes that far out.


.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 633 PM CDT Sun May 27 2018

For the most part, VFR conditions will prevail across the area
tonight and through the day Monday. The exception will be across
parts of the western CWA, where thunderstorms are expected to
develop this evening and into the early overnight hours. Periods
of MVFR cigs and IFR vsbys will be possible with the




LONG TERM...Telken
AVIATION...Parkin is the U.S. government's official web portal to all federal, state and local government web resources and services.