321 
FXUS63 KABR 191128 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
628 AM CDT Tue Oct 19 2021

.UPDATE...
Issued at 624 AM CDT Tue Oct 19 2021

See updated aviation discussion below.

&&


.SHORT TERM...(Today through Wednesday Afternoon)
Issued at 325 AM CDT Tue Oct 19 2021

An area of low pressure crossing the region later tonight through 
Wednesday will bring much colder temperatures, decent rainfall, and 
perhaps some light accumulating snow.

A cold front, weak surface trough, will slide across the area today, 
causing the winds to shift to the north-northeast and become breezy. 
The cold front will bring much cooler air into the CWA with highs in 
the upper 40s, in north central SD, to the mid to upper 60s, over 
east central SD. Low stratus in southern Canada could slide 
southward today, perhaps reaching the CWA during the mid morning 
hours. If the stratus does impact the area, then highs could be a 
bit colder.

A trough of low pressure currently over Utah will track into the 
area over the next 12 to 24 hours. It appears as though models have 
slowed the progression of this system, with pcpn reaching the 
western CWA mainly after 3Z. The pcpn slowly pushes eastward 
throughout the day on Wednesday, with the trowal feature shifting 
east into MN late Wednesday evening. Models appear to have shifted 
slightly southward with this system, with the heaviest pcpn 
occurring south of the ND/SD border, or perhaps south of Highway 12. 
Precipitation type is very challenging at this time. A few models 
are suggesting colder temperatures on Wednesday, which would bring 
snowfall further east, passed the Missouri River. There is even a 
couple showing snowfall reaching the James River valley Wednesday 
morning. Based guidance from WPC, HREF, and the 6Z HRRR, did bring 
light, accumulating snowfall further east, mainly along and west of 
Highway 83. With surface temps in the lower 30s, along with brief 
lift, snowfall amounts should range from a dusting to an inch or two 
on grassy areas. Rainfall amounts of 0.25 to 0.75 inches will be 
possible. Isolated thunderstorms within the warm sector of the 
surface low could produce higher rainfall amounts.


.LONG TERM...(Wednesday Evening through Monday)
Issued at 325 AM CDT Tue Oct 19 2021

The storm system set to affect the region in the short term period 
will be exiting to the east Wednesday night, with just some 
lingering showers still possible across the far eastern CWA 
Wednesday evening. High pressure then settles in over the region 
late Wednesday night through the day Friday, with dry and cool 
conditions expected. The high gets pushed east Friday night and 
Saturday as a trough digs down the lee of the Rockies. Dry 
conditions will continue during this time, with a decent pressure 
gradient likely resulting in windy condition on Saturday. The 
southern part of the trough looks to become a closed low over 
eastern Colorado/western Kansas on Saturday, which will then track 
east to east-northeast on Sunday and Monday, though there are some 
significant differences in the models on the strength and track of 
the system. However, there is a chance for precipitation on the 
north side of the low to reach South Dakota/west central Minnesota, 
so will stick with some low POPs during the Saturday night through 
Monday time frame. At this time, temperatures look to be warm enough 
for the precipitation to be rain. 

High temperatures will generally be in the upper 40s into the 50s 
through the period, with the exception of Monday when mid 50s to mid 
60s look likely. Overnight lows will be in the mid 20s to the lower 
30s Wednesday night, Thursday night and Friday night, then in the 
mid to upper 30s Saturday night and Sunday night.


&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 624 AM CDT Tue Oct 19 2021

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through the early morning hours. MVFR
cigs will spread from north to south during the day, along with
developing gusty north winds. A storm system will spread rain from
west to east across the area beginning tonight. Periods of MVFR
vsbys will be possible with the rain. Light snow may mix with the
rain at times across north central South Dakota after 08Z
Wednesday. 

&&


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

$$

SHORT TERM...SD 
LONG TERM...Parkin 
AVIATION...Parkin