000
FXUS63 KABR 230731
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
231 AM CDT Tue Apr 23 2024

.KEY MESSAGES...

- Cooler today with 15 to 30 mph sustained northerly winds this
  morning gradually easing off by late in the day.

- Pattern becomes more active by the end of the week, with
  increasing chances (60-90%) for showers and thunderstorms by
  Friday into the start of the weekend.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY AFTERNOON/...
Issued at 228 AM CDT Tue Apr 23 2024

At 2 AM CDT, skies are mostly clear. A surface pressure gradient
remains in place over the region, with a surface low centered over
southern Ontario and a surface high centered over the Pacific
Northwest. This is helping to get some of the stronger winds just
off the surface to occasionally mix down to the ground (gusts 25 to
30 mph). Temperatures are holding in the upper 30s to mid 40s.

Within a few hours of sunrise, look for much of the forecast area to
start efficiently mixing these stronger winds aloft down to the
ground, resulting in northwesterly surface winds quickly ramping
back up to 15 to 30 mph sustained with gusts up to 40 mph. As the
day wears on and pressure gradient relaxes, winds will begin to draw
down. Northwest flow aloft will be happening during the short term
period, all the while mid/upper level heights in that pattern will
be rising. At the surface, dry/stable surface high pressure will be
over the CWA from late today through Wednesday morning, with
southerly return flow pressure gradient setting up as the surface
high departs the region to the east.

The cooler temperatures today (925hpa thermal progs of +7C to +12C)
are expected to rebound on Wednesday (925hpa thermal progs forecast
to warm to ~+10C to +18C).

&&

.LONG TERM /WEDNESDAY EVENING THROUGH MONDAY/...
Issued at 228 AM CDT Tue Apr 23 2024

A couple of systems will affect the area for the long term. To
start, Clusters indicate a negative tilted trough over the Central
Plains by Friday morning. With this upper air pattern, ensembles
show slight chances of precip starting Thursday afternoon (15-30%
per NBM) as the surface trough/low part of the system pushes
northeast, with pops increasing to 60-70% Thursday night into the
overnight. The UL trough will continue its track northeast and into
the upper Midwest late Friday into Saturday. EC and Canadian
ensembles show this being a little deeper of a trough than GEFS.
Friday/Friday night looks to be our rainiest period for now as we
will be on the northern side of the low, as pops increase to 80-90%
over the entire CWA as that moisture really surges northward and
around low. 60-80% pops continue Saturday morning due to being west
of the low and dealing with wrap-around moisture.

Another trough will move in over the Southwestern US by Saturday
morning. At this point, Clusters are in pretty good agreement on the
position with GEFS wanting to keep the trough a little deeper than
EC/Canadian. It will then move northeast into the Central Plains. At
this point we start to see more discrepancies between the Clusters
on timing and intensity of this trough, so low confidence exits on
the exact outcome this far out. With its surface low, chances of
rain (30-60%) continue Sunday into early next week for now.

NAEFS indicates this moisture well as mean specific humidity values
range from 97.5-99% above climo at 850mb Thursday evening through
Saturday with mean precipitable water 90-97.5% above climo. EC EFI
indicates anywhere from 0.5-0.6 for Friday/Saturday. QPF wise, the
ensembles agree on the higher QPF from east central to northeastern
SD into western MN. Total QPF> 0.50" Thursday-Monday is 80-97% in
this area and decreases slightly over our central and western CWA.
Prob of 1" runs 40-85%, highest over our eastern CWA. Probability of
Cape>500 j/kg and bulk wind shear>30kts per ensembles is 10% or
less, so no organized severe weather is expected. This is backed up
SPC/CIPS/CSU keep the severe threat in the Central Plains where the
better moisture and forcing is. However, there looks to be enough
lift for some thunderstorms at times Thursday-Saturday.

Above average temperatures expected for Thursday as 850mb temps will
be +10 to 13C and forecasted surface highs in the upper 60s to mid
70s. A gradual cooldown is forecasted Friday-Sunday as highs for
Sunday are only forecasted to be in the upper 40s to the lower 50s
with temps rebounding to above average early next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1250 AM CDT Tue Apr 23 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through Tuesday, except perhaps around
KABR/KATY during the morning hours today where an occasional MVFR
cig could occur. Northerly winds will again turn gusty with
daytime heating later today.

&&

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

$$

SHORT TERM...Dorn
LONG TERM...MMM
AVIATION...Dorn