920 
FXUS63 KABR 190535 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1235 AM CDT Tue Oct 19 2021

.UPDATE...
Issued at 1232 AM CDT Tue Oct 19 2021

See updated aviation discussion below.


UPDATE Issued at 618 PM CDT Mon Oct 18 2021

The forecast remains on track this evening. No major changes are
planned. 

&&


.SHORT TERM...(This Evening through Wednesday Afternoon)
Issued at 359 PM CDT Mon Oct 18 2021

Some big changes weather-wise are expected across the area through 
the short term period. By Tuesday morning, a cold front will lead to 
a wind shift, from southerly to northeasterly, and bring in mid to 
low cloud cover. Winds will be breezy to windy, with gusts of 30 
plus mph possible mainly west of the Prairie Coteau through the 
afternoon due to a tightening pressure gradient. A nearly stacked 
low pressure system will track east along/near the South 
Dakota/Nebraska border Tuesday evening through Wednesday morning, 
likely bringing rain from west to east across the area. 0.25" to 
0.75" of total rainfall is possible by Wednesday evening, though the 
exact locations of heaviest amounts will depend on where exactly the 
deformation band(s) develop. Also, models are coming into good 
agreement about a changeover to snow across portions of central and 
north central South Dakota early Wednesday morning. Several factors 
complicate the snow accumulation forecast, namely the warm/wet 
ground conditions, but there may be localized areas where snowfall 
rates can be high enough for a few hours, leading to potential 
accumulations of an inch or more. Much colder air advects in behind 
the system on Wednesday, with highs in the 40s and lows Wednesday 
night in the mid to upper 20s.


.LONG TERM...(Wednesday Evening through Monday)
Issued at 359 PM CDT Mon Oct 18 2021

When the period opens, a low pressure system is pulling away from 
the region. Northeast surface winds will be diminishing overnight as 
northwest flow aloft develops. These northerly surface winds will be 
drawing what will feel like some pretty cold air down into the 
region Wednesday night. Climatologically speaking, though, this 
airmass won't be too far from what should be over the region at this 
time of year (perhaps just a tish below normal). This cold air looks 
to stick around for the rest of the week, while surface high 
pressure builds down into the northern plains. Airmass moderation 
theory appears to be the major influencer for temperatures for 
Saturday and Sunday, as low level thermal advection does not appear 
to be all that much. Monday is the warmest day of the period, but it 
looks like highs in the 50s to around 60 degrees. By the end of the 
weekend, an upper level ridge is forecast to move over and past the 
CWA, while a large broad cold upper level longwave trof carves out 
across the western CONUS.


&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1232 AM CDT Tue Oct 19 2021

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through Tuesday morning. In the 
afternoon, MVFR cigs and breezy northeast winds will move in 
ahead of a low pressure system that will bring some precipitation
to central South Dakota Tuesday evening. 

&&


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

$$

UPDATE...Wise
SHORT TERM...Lueck
LONG TERM...Dorn
AVIATION...Parkin