Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 281731 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1231 PM CDT Thu Mar 28 2024

.KEY MESSAGES...

- A disturbance moving through the region late tonight into
  Friday will deliver a 30-50% chance for rain and/or freezing
  rain. Up to a few hundredths of ice accumulation will be
  possible.

- Precipitation chances increase this weekend, perhaps in two
  waves, late Saturday/Saturday night, then again late Sunday
  through Monday. Early indications suggest a "less than 6 inch
  type outcome" for the time being.

- Warming temperatures moving in by mid-week next week, with 40s,
  50s, and perhaps even 60s (central SD on Wed) moving into the
  region.

&&

.UPDATE...
Issued at 1010 AM CDT Thu Mar 28 2024

The forecast remains on track this morning. No major changes are
planned.

&&

.SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/...
Issued at 445 AM CDT Thu Mar 28 2024

We`ll be able to squeak out another relatively quiet day weather-
wise today before a disturbance moves into our region toward the
latter half of the period and generate some precip chances for parts
of the forecast area. High pressure will gradually shift east and
southeast of our area today while a low pressure trough continues to
organize across the Rockies and Northern High Plains. With a ridge
of high pressure aloft, we can expect a fair amount of sunshine
during the day, perhaps high clouds filter out some of that sunshine
this afternoon. Warmer daytime highs are expected today, with
eastern zones the coolest thanks to thicker snow cover. A tighter
pressure gradient develops this afternoon across the western and
central Dakotas between the high to the east and the trough to the
west. Increasing southeast breezes gusting up around 30 mph will be
possible across the Missouri Valley.

Clouds will increase tonight as a sfc trough shifts eastward across
the Dakotas. The upper ridge will give way to an upper trough
lifting northeast out of the Rockies and Northern High Plains. We
anticipate light precipitation to develop and shift east-
northeastward across our forecast area tonight into Friday. Models
seem to be in agreement on the core of this disturbance to pivot out
of Montana and into North Dakota keeping the focus for steadier QPF
to our north. BUFKIT soundings do show a warm nose(above freezing)
aloft, just off the surface with temperatures at or colder than
freezing at the surface. That warm nose will take some time to
saturate, but eventually it looks to and we should see a period of
freezing rain spread across the forecast area late tonight into
Friday morning. WPC QPF and NBM generally are in the same camp
indicating up to a few hundredths of ice accumulation will be
possible across the northern tier of our CWA.

&&

.LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/...
Issued at 445 AM CDT Thu Mar 28 2024

Surface high pressure will be moving over the region Friday night
through much of the day Saturday, before pushing east Saturday night
as the first wave of precipitation chances approach. In regards to
the precipitation over the weekend into Monday, latest deterministic
solutions are starting to show this in two waves now, the first
being Saturday night, with the more meaningful onset of precip late
Sunday through Monday. Inherited NBM PoPs, as well as ensemble probs
for measurable still fail to adequately portray this given their
more blended/averaged feel. Will have to watch to see if this a
trend that holds.

By 00Z Tuesday, probability of exceedance for accumulated snowfall
greater than 3 inches (assuming 10:1 ratios) are running from around
40-60% across central SD, with lesser amounts around 40% or below
further east. Snowfall means amongst the GEFS/ENS/GEPS are running
around 2 to 4 inches by 00Z Tuesday, with some higher end scenarios
(75th percentiles) on the order of 4 to 6 inches (mainly over
central SD).

Looking ahead to mid-week next week, we see signs in the cluster
output of overall ridging trying to build across the Northern
Plains. There still area some glaring differences in the upper level
patterns amongst the four clusters in the 00Z Thurs - 00Z Fri
period. Clusters 2 and 3 (with 20% and 19% membership respectively)
hold on to a much deeper and slower moving trough over the Great
Lakes, which in turn show a large ridge amplification over the
High/Northern Plains. Cluster 1, which has the largest membership at
43%, shows a more flattened upper level pattern over the region, but
still mild nonetheless. The differences can be seen in 850mb temps
as well, with the more amplified ridge scenario running between +7C
to +12C across the CWA. Grand Ensemble of the clusters are generally
between +3C and +7C from east to west across the CWA. All that said,
the overall ridging moving in will mean a warm up into the 40s and
50s likely, perhaps even 60s on Wednesday across central SD
according to the inherited NBM temperatures.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1230 PM CDT Thu Mar 28 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions through this evening will deteriorate as a weak low
pressure system begins to affect the region late tonight. MVFR
cigs are expected to move in to KPIR and KMBG after 6z. Southeast
winds will shift to the northwest behind the low across central SD
Friday morning.

&&

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

$$

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


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