524
FXUS63 KABR 191841
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
141 PM CDT Sun Apr 19 2026

.KEY MESSAGES...

- Dry conditions are expected into the first half of this week
  with temperatures warming back above normal into Wednesday.

- There is a 30 to 50 percent chance of the region west of a
  line from Watertown to Ortonville picking up a quarter inch
  or more of rainfall Wednesday night into Thursday.

- Elevated fire weather conditions will return Monday with gusty
  winds and low relative humidity values expected across far
  eastern South Dakota over into Minnesota. Additional
  concerning fire weather conditions are being monitored for
  Wednesday afternoon.

- Strong sustained west-northwest winds 25 to 40 mph with gusts
  up to 50 mph are expected on Thursday.

&&

.DISCUSSION...
Issued at 139 PM CDT Sun Apr 19 2026

At 1 PM CDT, skies are sunny/mostly sunny and temperatures are
warming through the 30s and 40s. Surface high pressure is centered
north of the CWA, with north winds around 5 to 15 mph with some
occasionally higher gusts.

Northwest flow aloft holds the line until a vigorous/energetic upper
level longwave trof pushes the western CONUS upper level ridge
eastward over the region around mid-week. Given the synoptic-scale
set-up rolling into Wednesday night when the upper level low begins
to move out onto the central/northern plains states, could be seeing
the first taste of strong convection over this CWA for this
convective season. A lot will depend on from where the moisture for
thunderstorms will be coming. From Thursday through the start of
next week, the pattern aloft becomes quite blocky/stagnant, with a
blocking upper low off the CONUS east coast, essentially causing the
upper low/trof to stall out across southern Canada. The upper low`s
strong subsidence region is expected to glance this CWA heading into
Thursday. At this point, model progs and guidance suggest that a
wind advisory for westerly/northwesterly component winds is a slam
dunk for Thursday into Thursday night. The question is will there be
any counties in the CWA that experience High Wind Warning
conditions. The blustery winds look to persist into Friday as well.

Ensemble PoPs indicate that there is a 35 to 75 percent chance of
showers (thunderstorms is included here) Wednesday night into
Thursday. GFS soundings in BUFKIT indicate more than enough
instability at/above 2km for thunderstorms. Not much shear, though.
Presently, the probability of 0.25in or greater of precipitation
Wednesday night/Thursday is 30-50 percent west of a line from
Watertown to Ortonville. Eventually, additional shortwave energy is
expected to swing around the base of this upper trof and sweep
through the region, bringing some shorter-lived/lower-qpf potential
precipitation chances over the weekend into early next week.

The warm-up that begins on Monday is expected to continue into
Wednesday, when temperatures could be exceeding 90 degrees over a
good portion of the forecast area throughout and west of the James
River valley. The cold front that sweeps through the region
Wednesday night will signal a sharp drop in temperatures back down
into the 50s for daytime highs for most areas Thursday through
Saturday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1208 PM CDT Sun Apr 19 2026

Terminals KABR,KATY,KPIR,KMBG

There could be a few hours of low level wind shear potential
overnight at KPIR/KMBG. Otherwise, VFR conditions are forecast
through the period.

&&

.FIRE WEATHER...
Issued at 139 PM CDT Sun Apr 19 2026

Lots of dry air is expected to be around on Monday when low level
return flow southerlies get going. As temperatures warm into the 60s
and 70s on Monday, afternoon rh`s fall below 20 percent over much of
the western half of the CWA. However, the winds are forecast to be
relaxing over that area, at least, enough that Red Flag conditions
are not anticipated for 3 or more hours. However, on and east of the
Prairie Coteau, there are areas where rh`s are expected to be below
25 percent and wind gusts of 25 mph or more should last long enough
to satisfy Red Flag criteria.

A cold front is expected to switch winds around to the northwest
Monday night before they switch around to the southeast around 5 to
15 mph on Tuesday. Tuesday should also be about 5 to 10 degrees
cooler than Monday with higher afternoon relative humidity
everywhere across the region but south central South Dakota, where
afternoon humidity may fall to between 15 to 20 percent. Afternoon
southeast wind gusts could get up between 20 and 25 mph as well, so
south central South Dakota could be into some elevated fire weather
conditions.

Also, will be keeping a watchful eye on whether or not Gulf moisture
can make it this far north by Wednesday/can make a meaningful enough
dent on rh`s to preclude fire weather headlines that afternoon.
Right now temperatures warming into, at least, the 80s with
dewpoints up into the 30s and 40s won`t do it. Afternoon minimum
rh`s are progged to fall well below 20-25 percent CWA-wide on strong
southerly winds well beyond gusts of 25 mph. Wednesday could be
another fire weather headline day.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Fire Weather Watch from Monday morning through Monday evening
     for SDZ008-021-023.
MN...Fire Weather Watch from Monday morning through Monday evening
     for MNZ039-046.

&&

$$

DISCUSSION...10
AVIATION...10
FIRE WEATHER...10