394
FXUS63 KABR 271728 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1228 PM CDT Sat Apr 27 2024

.KEY MESSAGES...

- Lingering clouds today, with diminishing coverage of light
  rain/drizzle as storm system departs. Additional rain amounts less
  than one-quarter inch.

- Active pattern continues, with additional chance for rain Sunday,
  Tuesday, and Thursday. Rainfall amounts on Sunday have increased
  slightly, peaking around 1 inch in northeast SD, with lower
  amounts in western and central SD. The systems for next week have
  much lower overall moisture potential as well.

- Below to near normal temperatures through the extended.

&&

.UPDATE...
Issued at 1034 AM CDT Sat Apr 27 2024

Lowered pops through the afternoon. Otherwise, the forecast
remains on track this morning.

&&

.SHORT TERM /TODAY THROUGH SUNDAY AFTERNOON/...
Issued at 355 AM CDT Sat Apr 27 2024

Low pressure is centered over southern Minnesota early this morning,
with plenty of low clouds lingering over the CWA. Also seeing a few
pockets of light rain, with areas of drizzle as well. The drizzle
(and even fog) have developed generally east of the Missouri River,
and especially in the Coteau region where winds are lightest. Added
mention of drizzle/fog for the morning hours, but should see
visibility improvement as the north winds begin to increase. Also,
areal coverage of rain showers will be limited today as the low
pressure continues moving away from the region. Although, clouds
look to stick around, with HREF low cloud cover ensemble mean
staying rather high across the CWA through the day. So, will not see
much in the way of temperature rises today, with most areas stuck in
the upper 40s to mid 50s. Models suggest clouds will stick around
into the overnight hours as well, therefore leaned more towards
NBM75th for lows.

Next area of low pressure begins moving northward across the Central
Plains on Sunday, ending up somewhere near Sioux City or Omaha by
00Z Monday. This system will spread rainfall northward across the
area through the day Sunday. Due to a lack of instability, only
looking at a slight chance of embedded thunder. Examining
deterministic and ensemble/probabilistic data, it appears rainfall
amounts could range from around a half inch to 1 inch for eastern
portions of the CWA. Although, 75th percentile HREF members are
closer to 1.25 inches for eastern portions of the area.

&&

.LONG TERM /SUNDAY EVENING THROUGH FRIDAY/...
Issued at 355 AM CDT Sat Apr 27 2024

We will be stuck under the longwave trough over the next several
days, and while there will be variations in how broad this trough
is, the end result is an active pattern, with near to below normal
temperatures, though the extended.

Will open with a shortwave nearly overhead Monday morning, lifting
northeast. Probabilities for moisture still show a high range with
the 24 hour QPF 25th/75th percentiles for Aberdeen between 0.36 and
1.23... GEFS plumes show nearly an inch difference between the
higher end ensembles vs the lower...though the mean is much lower
compared to the deterministic QPF. A similar trend exists for
Watertown with more overall QPF, and for Mobridge/Pierre though with
lower overall QPF. Thus, key takeaway is that there is still quite a
bit of uncertainty in overall rainfall amounts.

A very short break will occur between systems, with the low
departing in the east and the next low developing over Wyoming
during the day Monday. The next shortwave track is almost directly
west to east, though the surface low is elongated, with a narrow
axis of milder air (warm tongue) being dragged up from the south
around then back into north central North Dakota. This warm air will
only be over us for a short period, mainly during overnight hours,
but as it mixes out Tuesday should see a rapid warmup. This is short
lived however, and there is a tighter thermal gradient behind the
system, despite a less intensely cold airmass in comparison to the
departing system Monday. The end result, overall less moisture with
this system, and more wind. Probabilities for exceeding 45mph are
limited to west of Mobridge (around 50 percent), otherwise the
25th/75th range is in the 30-35 to 40-45mph range.

Next system comes in late in the period (Thursday night/Friday) but
still quite a bit of uncertainty with track/timing, looking like it
will be a weak Colorado low type system with the Dakotas well north
of any spring-like warmth or humidity.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1226 PM CDT Sat Apr 27 2024

Terminals KABR,KATY,KPIR,KMBG

MVFR cigs will persist along with some patchy drizzle. Cigs are
expected to fall to IFR as rain moves in again toward Sunday
morning. Winds will remain out of the north to northeast with
occasional gusts to 25 kts.


&&

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

$$

UPDATE...Wise
SHORT TERM...TMT
LONG TERM...Connelly
AVIATION...Wise