Rousseau, South Dakota Weather Forecast Discussion

048
FXUS63 KABR 020947
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
447 AM CDT Thu Oct 2 2025
.KEY MESSAGES...
- Unseasonably warm temperatures continue through Saturday. Highs
will be in the 80s to lower 90s. These readings are 20-25 degrees
above normal. Highs on Friday and Saturday will be near record.
- Winds begin to increase on Friday and remain windy through Sunday
with gusts ranging from 30 to 40 mph.
- A cold front will bring rain Saturday night through Sunday, mainly
central and north central SD. A Marginal Risk for severe
thunderstorms, level 1 of 5, is in effect for Saturday night.
&&
.SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/...
Issued at 446 AM CDT Thu Oct 2 2025
Hot and dry weather continues today and Friday. The upper ridge
builds a little farther north into South Dakota today. Mixing is
limited today with weak low pressure at the sfc, but highs should
still climb into the 80s or about 20 to 25 degrees above normal.
Friday will be the hotter day as heights rise further and southerly
winds return ahead of a Rocky Mountain low. Near record highs are
expected at Watertown, Sisseton, and Pierre where forecasts in the
upper 80s to lower 90s are three degrees or less away from records
set in 1938. Wind gusts of 25 to 35 mph with drier southwest flow
aloft will also push grassland fire danger into the high category
mainly across portions of central SD from Pierre south. No fire wx
headlines yet as min RH remains above 25 percent.
&&
.LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/...
Issued at 446 AM CDT Thu Oct 2 2025
Guidance continues to come together for an upper-level trough to
move over the forecast area supporting a low pressure center over
eastern MT/WY and western ND/SD. This will re-introduce a tight
pressure gradient over the CWA, bringing strong southerly winds.
Sustained winds Saturday will reach around 20 miles per hour,
gusting to 35. The southerly winds occur ahead of the cold front
attached to this low pressure center, and therefore will mainly
impact northeastern South Dakota. Behind the front, winds veer to
the northwest, and will increase in strength. Winds tend to
overachieve the NBM under a northwesterly cold air advection regime,
so have made a targeted change to the forecast at this point. Wind
gusts behind the front will have broad coverage of 35 to 40 mile per
hour gusts, and NBM gives a 10-30% chance for gusts to 45 miles per
hour Sunday, the criteria for a Wind Advisory.
With this cold front, development of showers and potentially some
embedded thunderstorms is expected. Model soundings indicate only a
marginal severe threat, and confidence is low mainly due to a lack
of CAPE and uncertainty on mid-level lapse rates. A bit more
favorable of an anticipated threat is flooding due to heavy rain.
Over the past forecast cycle, PWATs and warm cloud layer have
increased (~1.2" and 8k feet respectively), while storm motion has
decreased (~10-15 knots). These variables are definitely not the
most favorable for flooding potential, but it is worth noting the
trends in the guidance nonetheless. The lack of CAPE will still be a
problem, but that may be counteracted by the front itself providing
the necessary lift. Soils there would be best described as
"moderately saturated" - that area was hit with a lot of rain with
the last event, but there has been enough of a dry period to where
soils have dried out a bit, currently in the 30-40% range.
Therefore, it would take a bit of rain to saturated the soils
(values of around 50% is a general estimate of what it tends to take
to start flooding in that area), but the antecedent conditions may
not be able to take significant amounts of water either. 50th
percentile 24 hour rainfall values (ending at 00Z Monday) from the
NBM are between 1.25"-2" over Corson and Dewey county, again a
significant increase from the forecast 24 hours ago. Probability of
1" of rainfall in 24 hours is 50-70% over that same area, and
probability of 2" of accumulation is 10-40%. Other areas may see up
to an inch of rain, but the current guidance would suggest chances
of anything more are low outside of the Corson/Dewey county area
talked about above. Trends in the forecast will continue to be
monitored as the system approaches.
We continue to monitor the potential for frost or even a freeze next
week behind the passage of the cold front. Morning low temperatures
Monday through Wednesday may dip into the upper 30s at times, with
Wednesday morning currently expected to be the coldest. A high
pressure center will have move over the CWA, which signals a
potential for clear skies and light winds, factors conducive to
cooler overnight temperatures. The latest NBM gives a 30-50% chance
to see 36 degrees or lower (the upper limit for frost formation) on
Monday and Tuesday mornings over north central South Dakota, and a
broader 40-70% on Wednesday morning. Probability for a freeze
currently sits at around 10-30% over north central South Dakota
Monday and Tuesday morning, and 30-50% Wednesday morning.
&&
.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1227 AM CDT Thu Oct 2 2025
Terminals KABR,KATY,KPIR,KMBG
VFR conditions are forecast through the TAF period, along with light
winds.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
SHORT TERM...20
LONG TERM...BC
AVIATION...20

NWS ABR Office Area Forecast Discussion