105
FXUS63 KABR 052321 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
621 PM CDT Tue May 5 2026

.KEY MESSAGES...

- Mostly dry forecast with weak systems/light amounts of
  moisture Thursday night and Saturday.

- Below normal temperatures (5 to 15 degrees) tonight/Wednesday.
  Near-normal temps Thursday-Saturday.

&&

.UPDATE...
Issued at 620 PM CDT Tue May 5 2026

See below for an aviation forecast discussion for the 00Z TAFs.

&&

.DISCUSSION...
Issued at 1259 PM CDT Tue May 5 2026

Cloud covers most of the CWA with some light returns but not actual
moisture on any webcams or sensors. Temperatures have stalled in
the 40s.

Current NBM deterministic values drop temperatures to around mid-
upper 20s which is fairly close to the mean, however we do have the
broad areas of mid level cloud cover thanks to daytime heating of
this cool airmass. Upstream cloud cover includes some stratus in
central Saskatchewan which may survive the loss of daytime heating, and
pivot down into the northeast CWA tonight. Otherwise, the HRRR shows
cloud cover dissipating across the area this evening with loss of
daytime heating for ideal radiation conditions with dewpoints in the
teens and evening temperatures in the 40s. The surface high is still
off to the northwest with a ridge extending down across the area,
meaning a light gradient will still be in place so winds won`t
totally go slack. Will trend towards the 25th percentile temperatures
tonight.

Overall, the upper flow trajectory remains out of the northwest,
with some variation in the intensity of the upstream ridge. Flow is
initially out of central Canada but shifts more towards western
Canada as a source region, which will temper temperatures towards
seasonal for the latter half of the work week. Another northwest
flow wave/clipper brings in some colder air for the weekend (though
less so in comparison to the current cold snap), before shifting
back towards the western Canada source region. Either way, we`ll be
a couple of degrees either side of normal late week/weekend.
Interesting to note that the deterministic NBM falls around the
lowest 25th percentile for Thursday through Saturday. Overall range
in the 25th-75th percentiles is 5 to 8 degrees F which in the grand
scheme of weather days 3-7 isn`t all that much.

As for moisture, still not looking for any major drought relief. Got
the weak/disorganized system for late Thursday/early Friday. NBM
probability of exceeding 0.1" is only 10-20%, and most of the GEFS
members fall to around 0.05" if they produce anything for Pierre
(there are 2 outliers >0.1"). Another clipper-like wave follows for
Saturday. Not a lot of confidence in this one either, with the
GFS/EC/Canadian all showing slightly different areas of warm
advection band rainfall in ND and the Western Lakes region, with
another area of higher moisture over the western Dakotas.  NBM
probability of exceeding 0.01" is from 10% across the northeast to
40% across the western CWA. GEFS plumes show most of the spread in
members is between 0 and 0.2" with just a few outliers higher.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 620 PM CDT Tue May 5 2026

Terminals KABR,KATY,KPIR,KMBG

VFR ceilings are supposed to dissipate at some point between now
and 06Z over most of the region, including all four terminals.
On Wednesday, broken/overcast VFR ceilings are forecast to
return, once more, over at least northeast South Dakota into
Minnesota (perhaps the KABR/KATY terminals?) by 18Z and persist
through the afternoon. Winds out of the northwest go light
tonight, and then pick back up to around 10 to 15 knots out of
the northwest on Wednesday.

&&

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

&&

$$

UPDATE...10
DISCUSSION...07
AVIATION...10