Lily, South Dakota Weather Forecast Discussion

978
FXUS63 KABR 280434
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
1134 PM CDT Sat Sep 27 2025
.KEY MESSAGES...
- Above normal temperatures (10-15 degrees above normal) plus dry
and windy conditions will return for the end of the weekend into the
first half of next week.
&&
.UPDATE...
Issued at 558 PM CDT Sat Sep 27 2025
The forecast remains on track, with limited updates are expected
to the ongoing forecast this evening.
&&
.DISCUSSION...
Issued at 338 PM CDT Sat Sep 27 2025
The center of a sfc high pressure system across eastern SD and
western MN will gradually drift eastward tonight and eventually set
up closer to the western Great Lakes on Sunday. Meanwhile, sfc low
pressure/lee side troughing will organize across the Northern High
Plains/western Dakotas during this time frame. If there remains any
leftover northerly winds this evening in our eastern zones, they
should progressively become more southerly tonight while the rest of
the forecast area will see southerly low level flow continue to take
hold. This should help in maintaining more mild overnight lows
compared to this morning`s temperatures in the upper 30s to mid 40s.
Tonight`s lows are expected to bottom out in the upper 40s to mid
50s from east to west across the CWA.
Upper level ridging will start to build into the Northern Plains
later tonight into Sunday which will set up a warmer and continued
dry trend for the end the weekend. The aforementioned sfc pattern
will more or less remain constant on Sunday through at least the
middle of the upcoming new week. An abnormally warm air mass will
begin to set into the region. 850mb temperatures are still
anticipated to be well above the 90th percentile for late September.
Values of +20C or warmer are progged for most of the forecast area
on Sunday which should equate to widespread afternoon highs topping
out in the low to mid 80s. A tightening sfc gradient(10-12mb from
northwest SD to southeast SD) Sunday will lead to increasing
southerly winds by late morning and midday. Peak gusts during the
afternoon look to range between 25-35 kts. NBM probabilities of
seeing winds reach Wind Advisory criteria(30 mph sustained/45 mph
gusts) are very limited for our forecast area. Portions of our far
southern zones or along and south of the I-90 corridor see probs
approach 50% Sunday afternoon with a better chance south of our CWA.
Drier low level air looks to persist across our eastern zones during
the day and did make some effort into holding dew points lower
across northeast SD and west central MN. With temperatures expected
to warm into the low to mid 80s across most of the forecast area,
this does result in afternoon RH values falling into the mid 20
percent range in northeast SD and west central MN. With winds albeit
breezy to gusty at times, those eastern zones should not see wind
gusts getting to critical levels that would warrant any fire weather
concerns. Also, a corridor of stronger 1/2km winds of 30-35 knots
will take a downward trend toward 25 knots during the peak heating
afternoon hours. Low level moisture looks to recover better across
central SD Sunday with dew point temperatures warming at least into
the low to mid 50s which will help maintain higher min RH values in
the 35-45 percent range.
Going into the new work week, southerly flow at the sfc and aloft
will be maintained allowing for the warmer than normal air mass to
persist. The upper flow pattern will feature successive upper level
shortwaves coming in from the monsoonal flow across the Desert
Southwest. Increasing mid level moisture will be pulled into the
region thanks to this set up. Some of the CAM`s/deterministic
solutions do show there could be a few elevated showers developing
early Monday across south central SD in response to the initial
shortwave energy and a stronger nocturnal low level jet developing.
However, continued to stick with a dry forecast at this time as
confidence remains low. It`ll be an interesting feature though to
keep an eye on. The overall trend through the latter half of the
forecast period does continue to indicate above normal temperatures
and dry conditions. By late in the period, or late in the work week,
deterministic/ensembles do show an upper trough developing across
the Pac NW/Northern High Plains. This may provide some impetus in
returning some precipitation into the region at that time.
&&
.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1134 PM CDT Sat Sep 27 2025
Terminals KABR,KATY,KPIR,KMBG
Expect VFR conditions over the next 24 hours. Winds 30-35kts will
be just above the surface overnight into Sunday morning (while
near 25-30kts at ATY). Low level wind shear may be possible, and
we`ll continue to monitor the latest trends, but it has not been
included in the forecast at this time. Low level wind shear is
more likely at both PIR and MBG late Sunday night.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...06
DISCUSSION...Vipond
AVIATION...06

NWS ABR Office Area Forecast Discussion