Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 262050
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
350 PM CDT Mon Jun 26 2017

.SHORT TERM...(This Evening through Tuesday Afternoon)
Issued at 347 PM CDT Mon Jun 26 2017

As of 20Z, the region is situated under northwest flow aloft with a
high pressure at the surface. This high pressure will drift
southeast of the region tonight allowing for southerly winds to
develop. With 0-0.5km winds increasing to 20-35 knots before
sunrise, low temperatures tonight will range in the upper 40s, to the
mid 50s. This CWA will continue seeing windy conditions on Tuesday
as a low pressure system develops west of the region. Based on
buffer soundings, winds may briefly exceed wind adv criteria in
central South Dakota. Since it`s marginal, will hold off on a
headline. Good WAA during the afternoon hours could lead to
convection in NE South Dakota and western MN.

The main focus for severe weather will be late Tuesday afternoon
along a frontal boundary. Models show thunderstorms developing over
the Black Hills region around 21Z. These storms will continue to
intensify as the track eastward into a moderately unstable
environment. The strong to severe storms could reach our far western
CWA between 23-0Z. Chances are best beyond the short term.


.LONG TERM...(Tuesday Evening through Monday)
Issued at 347 PM CDT Mon Jun 26 2017

Forecast models maintain that the forecast period contains a rather
active weather pattern, of seeing potential weather systems appx
once every couple of days.  No prolonged periods of extreme heat or
cold. Just a busy thermal advection pattern.

The period opens with a potential round of strong to severe
thunderstorms developing/moving into the forecast area. Mid-level
waa will have warmed temps up enough to cap off daytime convection,
but as a cold front begins to push into the region from the west
early Tuesday evening, expecting at least isolated to scattered
coverage of thunderstorms (supercells most likely) to develop with
large hail and damaging winds possible. If convection rooted in the
boundary layer gets going along/west of the Missouri River valley
Tuesday evening, there will be no lack of low level moisture/jet
activity overnight to feed convection. It`s entirely possible, given
amount of low level shear around Tuesday night, convection may
evolve into one or two MCS`s with a continued wind threat extending
as far east as the Prairie Coteau late Tuesday night/early Wednesday
morning.

A couple model solutions still hint at a secondary round of showers
working into the forecast area by late in the day Wednesday.
However, most 12Z model runs today are still hinting at potential
for showers and thunderstorms is more probable by Thursday evening
lasting into the day on Friday, and then again by late in the day
Sunday into Sunday night. Deterministic and ensemble thermal progs
indicate temperatures will be hovering right around climo average
for late June/early July, give or take a few degrees. Perhaps by
early next week, temperatures could be rising to values 5 to 10
degrees above normal. Will continue to monitor 4th of July
temperature trends.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 1233 PM CDT Mon Jun 26 2017

VFR conditions can be expected through the valid taf period.
Increasing southerly winds later tonight could produce a wind
shear for KPIR. All areas will see gusty winds by 15Z Tuesday.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

SHORT TERM...SD
LONG TERM...Dorn
AVIATION...SD


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