339
FXUS63 KABR 191931
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
231 PM CDT Tue May 19 2026

.KEY MESSAGES...

- Frost/freeze expected early Wednesday morning across the region as
  lows drop into the upper 20s to low 30s.

- Rainfall chances increase to 60-70% on Friday. Amounts
  generally between 0.25-0.75in and very limited threat for
  severe storms.

- Turning warmer late weekend/early next week, about 10 to 20
  degrees above normal with highs in the 80s to near 90.

&&

.DISCUSSION...
Issued at 231 PM CDT Tue May 19 2026

Plenty of stratocumulus clouds remain across the CWA this afternoon,
but with high pressure and drier air working into the region into
this evening, expect gradual clearing from west to east. Winds will
also become light and variable this evening before switching to the
south-southeast late tonight. Rather good radiational cooling
conditions setting up tonight, especially over the eastern CWA.
Expecting temperatures to drop into the upper 20s to low 30s across
most of the CWA, so will therefore stick with the frost/freeze
headlines. Frost advisories were buffered around the original Freeze
Warning.

On Wednesday, surface high moves east into MN while a surface trough
takes shape over eastern MT and WY. This will tighten the pressure
gradient across SD, especially central SD where southerly winds are
likely to gust between 30 and 40 mph by late morning. Don`t see a
need for an advisory at this point as even NBM90 wind gusts are
below 45 mph.

Focus then shifts to the approaching upper trough and associated
surface trough/low that moves into the region Thursday night through
Friday. Models starting to come into better agreement with
increasing chances (60-70%) for rainfall across the region.
Instability looks somewhat limited though and SPC outlook, as well
as ML outlooks don`t highlight any severe storm potential over the
Northern Plains. As for rainfall amounts, NBM mean-75th spreads in a
48-hr time frame ending at 12Z Saturday generally range from around
0.30in to 0.75in.

Warming trend still showing up in the models towards the latter half
of the weekend into early next week as Grand Ensemble 850mb temps
increase to around +15C to +18C across the CWA during this time.
Inherited NBM high temps are in the 80s Sunday through at least
Tuesday of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1230 PM CDT Tue May 19 2026

Terminals KABR,KATY,KPIR,KMBG

CIGs have generally improved to VFR early this afternoon and are
expected to remain that way through the remainder of the day
before SKC conditions take over tonight. Light winds tonight
will increase from the south on Wednesday with gusts close to 30
knots across central SD (KPIR/KMBG).

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Frost Advisory from 1 AM CDT /midnight MDT/ to 8 AM CDT /7 AM
     MDT/ Wednesday for SDZ003-015-033-045-048.
     Freeze Warning from 1 AM to 8 AM CDT Wednesday for SDZ004>011-
     016>023-034>037-051.
MN...Frost Advisory from 1 AM to 8 AM CDT Wednesday for MNZ039-046.

&&

$$

DISCUSSION...TMT
AVIATION...TMT