FXUS63 KFSD 270831

AFDFSD



Area Forecast Discussion

National Weather Service Sioux Falls SD

331 AM CDT Mon Oct 27 2025



.KEY MESSAGES...



- Rainfall onset looks slower today, but spotty light showers or

  sprinkles should develop this afternoon. Rainfall amounts may

  approach 0.10" toward central South Dakota, but most areas

  will see a few hundredths of an inch at best through sunset.



- More widespread rain is expected later this evening through

  Tuesday evening, especially along/east of I-29. This area

  continues to see 40-60% chances for rainfall exceeding a half

  inch. 



- Near to slightly below normal temperatures dominate this 

  week, but warmer temperatures may be more promising for the 

  latter half of next weekend.



&&



.DISCUSSION...

Issued at 330 AM CDT Mon Oct 27 2025



TODAY: Well-advertised mid-upper level trough moving across the

northern Rockies toward the High Plains of the Dakotas early

this morning. With a strong downstream blocking ridge, timing of

this trough has trended slower, with impacts for our forecast

area two-fold for today. While areas west of U.S. Highway 281

may see a few light showers this morning, most areas will remain

dry until a couple of weak mid-upper level waves move into the

area this afternoon. This should still promote development of

light showers/sprinkles for most of our area, though amounts

through the daytime hours will be quite light with most areas

seeing a few hundredths at best. Weak mid-level instability 

toward central South Dakota may support a few moderate showers 

or even an isolated thunderstorm by late afternoon, which could

push amounts toward a tenth of an inch. Despite lower rainfall

chances, cloud cover will be abundant, limiting highs to the 50s

for most locations.



TONIGHT-TUESDAY NIGHT: The blocking ridge over the Great Lakes

and eastern Canada will force additional energy to dig into the

central Plains. A north-south band of mid-level frontogenesis 

strengthens ahead of the trough late tonight, with some model

solutions showing this frontogenesis persisting along/east of

I-29 through much of Tuesday. This lift will interact with a

plume of deeper moisture over the eastern half of our forecast 

area, resulting in more widespread rain development by late 

tonight. Periods of rain will persist near and especially east

of I-29 Tuesday into Tuesday evening before the upper level low

pulls southeast into the mid-lower Mississippi Valley. Rainfall

amounts should be higher with this phase of the system and while

totals are still being ironed out, ensembles continue to show

moderate (40-60%) probabilities of 24-hour rainfall exceeding a

half inch, highest east of I-29. The rain/clouds along with a

generally cooler air mass will lead to below normal highs on

Tuesday in the upper 40s to lower 50s.



WEDNESDAY ONWARD: Seasonably cool northerly flow will dominate 

much of the mid to late week period, though any periods with a 

more westerly low level flow could see a brief warm-up. While 

there is some consensus among 00Z deterministic models showing 

weak ridging Thursday ahead of stronger low pressure dropping 

southeast through North Dakota/Minnesota Friday-Saturday, the 

broader ensemble still shows more variance in possible timing 

and strength of any waves. Thus, confidence in seeing greater

temperature swings or light precipitation chances by late week

into next weekend is low.



&&



.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...

Issued at 1015 PM CDT Sun Oct 26 2025



Mostly VFR conditions will transition to mainly MVFR conditions

this TAF period. Taking a look at satellite imagery, low to mid

level clouds continue to filter into the region from west to

east this evening promoting occasional MVFR ceilings. Expect

these MVFR ceilings to become more widespread after sunset as

low hanging stratus surgeseastwards with decreasing temperatures

across the area. Otherwise, intermittent periods of showers 

will develop throughout the day as a as a cold front progresses

through the region. Lastly, southerly surface winds will 

gradually decrease overnight before increasing again on Monday 

with gusts between 25-35 mph expected.



&&



.FSD WATCHES/WARNINGS/ADVISORIES...

SD...None.

MN...None.

IA...None.

NE...None.



&&



$$



DISCUSSION...JH

AVIATION...05