963
FXUS63 KABR 071407 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
907 AM CDT Mon Apr 7 2025

.KEY MESSAGES...

- Temperatures today will be 5 to 20 degrees below normal.

- There is a 20-35% chance of light showers Tuesday night through
Wednesday night. Little to no accumulation is expected at this time.

- Temperatures will be on a steady increase through the week,
peaking next Saturday and Sunday in the 70s, which is 10 to 20
degrees above normal.

&&

.UPDATE...
Issued at 901 AM CDT Mon Apr 7 2025

No changes planned to the today period forecast.

&&

.SHORT TERM /TODAY THROUGH TUESDAY AFTERNOON/...
Issued at 314 AM CDT Mon Apr 7 2025

The main area of high pressure remains over Manitoba, but the ridge
extends over the Dakotas and northern MN as of 08Z. The ridge will
continue to build in this morning and shift to the eastern Dakotas
by 18Z and MN by 03Z Tuesday. Today will be cooler, with highs in
the mid 30s to upper 40s. The 500mb ridge over MT/ID and down
through southern CA will shift over the western Dakotas by 06Z
Tuesday and be over our forecast area during the daytime hours
Tuesday.

Tuesday will be a transition day as the much warmer air moves in for
the rest of the work week. A trough of low pressure will move over
western South Dakota in the afternoon. The strongest warm air
advection over eastern NE into south central SD Tuesday afternoon.
Expect winds Tuesday to be out of the south to southeast gusting 20
to 25 mph, and decreasing over central South Dakota from mid
afternoon on as the surface trough moves in. Relative humidity
values will be similar to today, in the 25 to 35 percent range west
of the James River and closer to 40 percent elsewhere. Timing the
strongest winds, with the given temperatures and relative humidity
gives us a return of high Grassland Fire Danger Index values for 5
of our south central county warning area.

&&

.LONG TERM /TUESDAY EVENING THROUGH SUNDAY/...
Issued at 314 AM CDT Mon Apr 7 2025

Will start off early Wednesday morning with an upper low over
Montana/southwest Canada and strong easterly flow over the northern
Rockies. A second weak shortwave develops in response to the left
exit region overhead but that moves east and away from the CWA
during the day, with the Montana wave moving southeast across
North/South Dakota early Thursday, all while the overall upper
flow/jet transitions from zonal/ridging to a trough overhead in
about 36-48 hours.  Continue to see low probabilities for moisture,
with low confidence on timing from deterministic models. Probability
of 0.25 inches remains less than 10% and 0.10 inches is down to
around 10-20%. There is an added layer of uncertainty as profiles
now indicate some skinny mid level CAPE (NAM with about ~150j/kg).
NBM range is closer to 30-150j/kg (25th to 75th percentile) so the
NAM is a bit on the higher scale. Either way, precipitation will
take on some showery aspects.

A high amplitude ridge follows for Friday/Saturday, folding over as
a longwave trough is positioned over the western CONUS. Confidence
is lowering as this comes onshore and breaks up with a southern and
northern shortwave developing across all 3 deterministic models. NBM
dewpoints have taken a notable drop, along with much of the CAPE
that were advertised 24 hours ago with the NBM 75th running up to
500j/kg across the southern half of SD, while the 25th percentile is
essentially zero. More impressive is the warmth that this will draw
northwards, with 850/700mb temperatures increasing to a standard
deviation above climo. The result will be high temperatures into the
70s which is some 10-20 degrees above climo for the weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 603 AM CDT Mon Apr 7 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period.


&&

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

$$

UPDATE...10
SHORT TERM...06
LONG TERM...07
AVIATION...06