820 
FXUS63 KABR 080525 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1225 AM CDT Fri Oct 8 2021

.UPDATE...
Issued at 1223 AM CDT Fri Oct 8 2021

Aviation discussion updated below for the 06Z TAFs.

UPDATE Issued at 821 PM CDT Thu Oct 7 2021

No changes planned to the tonight period forecast.

&&

.SHORT TERM...(This Evening through Friday Night)
Issued at 307 PM CDT Thu Oct 7 2021

A surface front currently extends from northeastern North Dakota to 
southwestern South Dakota, and looks to gradually track eastward to 
central South Dakota tonight and Friday before becoming reinforced 
by a stronger low moving in from the west Friday night. Weak upper 
level ridging on Friday will give way to shortwave energy riding up 
the east side of an upper trough Friday night. Southerly flow ahead 
of the front will continue to usher warm air into the region, making 
for another warm day on Friday. Tonight will be dry, and most models 
and high res CAMs indicate the daytime hours on Friday will be dry 
as well, likely due to the the weak ridging over the area, with H7 
temps between +4C and +6C (possibly enough of a CAP for this time of 
year). As the stronger surface low moves in Friday night, will 
likely see a better chance for precipitation, mainly during the late 
evening and overnight hours. Cannot rule out the potential for 
thunderstorms, as there will be some weak CAPE, bulk shear of 30-40 
knots, and the development of a 30-35 knot low level jet. The latest 
SPC convective outlook moved the marginal risk north out of all but 
the far northern CWA, so do not expect most of the area to see 
severe weather Friday night. 

Low temperatures tonight will be mainly in the 50s, with highs on 
Friday in the mid 70s to lower 80s. Lows Friday night will again be 
in the 50s.

.LONG TERM...(Saturday through Thursday)
Issued at 307 PM CDT Thu Oct 7 2021

An active weather pattern is expected across the region through the 
long term portion of the forecast.

The period begins on Saturday with an upper level trough, surface 
low pressure system and cold front crossing the region. Isolated to 
scattered showers and thunderstorms should develop along the cold 
front as it pushes across the CWA. Excellent deep layer shear, along 
with some instability, steep mid level lapse rates could cause a 
few strong storms with hail possible. Timing of the front is a 
little problematic as the NAM is faster, with storms along the 
James River between 17-20Z, while the GFS is slower, with storms 
mainly west of the James River at 0Z Sunday. If the NAM is 
correct, then the severe threat will be best over northeastern SD 
and western MN during the afternoon hours. If the GFS is correct, 
the severe threat is rather marginal, and best along and north of 
the ND/SD border. The convective potential wanes quickly after 0Z 
as instability significantly decreases. Light showers, breezy 
northwesterly winds can be expected Sunday morning, with dry 
conditions Sunday night through Tuesday morning. 

A strong area of low pressure and upper level trough will impact the 
region midweek, Tuesday evening through Wednesday evening. This 
system is slow moving and should produce significant rainfall, 
especially to the drought areas. Winds will be gusty from the west 
to the north, northwest as the storm progresses across the region. 
There is some minor placement issues with the surface low, which 
would cause some variations with temperatures. A further west track 
would produce warmer temperatures, while an easterly track would 
bring colder temps. As of now, temperatures should be warm enough to 
support all rain. Dry conditions are expected behind this system.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1223 AM CDT Fri Oct 8 2021

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail across the area through the TAF period. 
A cold front (on top of KMBG at this time) will be slowly working 
its way across the region over the next 24 to 36 hours. Winds will 
be prevailing from a northeast or north direction at KMBG. 
Otherwise, eventually the southerly winds out ahead of the boundary 
will be switched around to a northeasterly direction and then a 
north-northwesterly direction, first at KPIR by morning, then by 
late in the day at KABR. By the end of the TAF valid period, the 
boundary should be near KATY. Also, by the end of the TAF valid 
period, rain chances start to pick up, mainly across north central 
South Dakota (KMBG terminal).

&&

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

$$

UPDATE...TMT
SHORT TERM...Parkin
LONG TERM...SD
AVIATION...Dorn/TMT