Area Forecast Discussion
Issued by NWS Aberdeen, SD
FXUS63 KABR 292334 AAB
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
634 PM CDT WED JUN 29 2016
Issued at 627 PM CDT WED JUN 29 2016
See updated aviation discussion below.
.SHORT TERM...(This Evening through Thursday)
Issued at 254 PM CDT WED JUN 29 2016
Forecast challenges in the next 24 hours include convective
potential/timing/coverage this afternoon through early Thursday
along with how cool high temperatures will be on Thursday.
Currently, temperatures are warming through the 80s on light winds
and a mostly sunny sky. There are a few clusters of thunderstorm
activity across southwestern North Dakota tracking southeast across
the region. Storms are not expected to maintain or redevelop very
far into this CWA. If convection can hold together long enough to
make it into Corson county, it is timed to move into the county
within the hour, and timed to reach Mobridge by shortly after 7 PM
CDT. Storms have developed within the most moisture-rich air at
850hpa in conjunction with the area of best mid-level forcing and
upper level lift. Expect the worst conditions associated with these
thunderstorms to be brief strong wind gusts /large temp-dewpoint
depressions aiding in 1000-1400J/kg DCAPE values/, heavy downpours
and cloud to ground lightning.
Tonight, a strong Canada-sourced cold front /near the international
border/ will sweep southward across the northern plains, including
this CWA, wringing out any available low level moisture through
Thursday morning. CAMs have been hinting off and on today that
isolated to scattered showers and thunderstorms will work southward
through the region associated with the forcing from this front. For
this reason have continued to time some small pops through the CWAovernight.
The Rapid Refresh model is also continuing to imply some of this
low level moisture is converted into post-frontal mvfr/vfr stratus
which advects into the CWA between 09Z and 15Z Thursday. Sky covermay
need a little tweaking if that scenario pans out.
Thursday, the cold air advection noted in the 925hpa and 850hap
thermal progs lends support to forecast high temperatures only in
the mid 70s across northeast South Dakota and west central Minnesota
to the low/mid 80s over central South Dakota. There may be a few
stray showers or weak thunderstorms ongoing across the southern half
of the CWA at the start of the Thursday day period, but by and
large, Thursday is expected to be cool and dry on northerly breezes.
.LONG TERM...(Thursday Night through Wednesday) Issued at 254 PM
CDT WED JUN 29 2016
Based on the 12Z model runs, the holiday weekend is looking much
drier than before. While models are suggesting a storm system will
track across the region Friday night through Saturday, it largely
misses this CWA. Thus pops have been greatly reduced during that
time period. There are additional chances for showers and
thunderstorms Monday through Wednesday as the upper level flow
pattern becomes zonal.
Temperatures during the long term will begin on the cool side with
highs on Friday only in the mid to upper 70s. Temperatures will
slowly warm above normal for the holiday weekend. Highs by Monday
should climb into the 80s and 90s. Temps in the 90s are expected
Tuesday and Wednesday.
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 627 PM CDT WED JUN 29 2016
An area of showers and thunderstorms will track across the
southwestern CWA this evening...affecting KPIR. Additional
scattered showers and thunderstorms may affect parts of the north
central and eastern CWA as well. Cigs and vsbys may briefly fall
into the MVFR category with the stronger storms. VFR conditions
will prevail across the area late tonight and through the day