259
FXUS63 KFSD 251122
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
622 AM CDT Sat May 25 2024

.KEY MESSAGES...

- Seasonal temperatures expected for the holiday weekend with
periodic chances for showers and thunderstorms. The overall severe
weather threat remains low.

&&

.DISCUSSION...
Issued at 318 AM CDT Sat May 25 2024

The leading edge of a weak piece of mid level energy will move into
the area this morning but not bring much with it. For the most part
the atmosphere is very dry below 700 mb so the only thing available
to produce precipitation is moisture in the dendritic layer, which
is very high, and any instability in the EML, which is pretty weak.
So, for the most part just expecting some sprinkles with a small
chance for a hundredth or two if some slightly higher instability
comes around. This potential will mainly be this morning into early
afternoon and north of I-90. By late this afternoon and tonight
showers and a few thunderstorms will be possible but right now
instability looks pretty weak. Both the GEFS and EC Ensemble
showing about 20% chance or lower of 500 J/kg CAPE near the
Missouri River with almost no chance for 1000 J/kg CAPE anywhere.
The slightly better chance for the higher CAPE values will be
central SD late this afternoon then down the Missouri River into
northeast NE and northwest IA later tonight. Not too dissimilar
to Thursday night, just less instability and a weaker wave.
Suspect with the decent little wave moving through NE tonight
some showers will develop with the best chance for the better
ingredients for storms and very isolated severe weather to come
together in northeast NE and northwest IA from about 10 pm to 5
am. Once again, chances look pretty low but a couple of stronger
updrafts not out of the question. One thing to watch out for is
with a pretty dry sub cloud layer there could be some wind that
sneaks north out of the potentially stronger convection in NE.

Otherwise for today it will be warmer but once again windy. Not as
windy as Friday but still some stronger winds this morning into early
afternoon. Suspect some gusts of 35 to 40 mph.

Sunday should see roughly two areas with potential for showers and
thunderstorms. The first will be the wave moving through NE which
should bring some forcing and moisture north towards northeast NE
into northwest IA, especially in the afternoon and evening. Overall
the instability is pretty weak so right now not concerned about
severe weather. The other area will be a wave moving through
southern ND which may spark some showers or isolated thunderstorms
in central SD late afternoon and evening then mainly north of I-90
during the evening into Sunday night. This area also appears to pose
no severe weather threat.

Once this wave passes on Sunday night a cooler pattern with below
normal temperatures is expected Monday and Tuesday. A wave passes by
through MN on Memorial Day and could allow for a few showers and
isolated thunderstorms mainly east of the James River.

Upper level ridging builds into the area Wednesday and Thursday
which should bring back normal to above normal temperatures.
Wednesday should be dry, but with troughiness developing over the
Northern Rockies on Wednesday night Thursday into Friday will likely
see the next chances for showers and thunderstorms.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 620 AM CDT Sat May 25 2024

A mid level deck of clouds will move in late morning through the
afternoon. Some very weak instability may allow some light rain to
fall but overall should mostly be something closer to sprinkles.
Late this afternoon into the early evening a few stronger storms
will be possible near and west of the James River, a few of these
storms could contain hail and strong winds. Continued development of
showers and isolated thunderstorms will be possible from about 2z
through 8z in southeast SD and southwest MN. Later tonight, mainly
after about 4z a few more strong thunderstorms will be possible near
the Missouri River near northeast NE then into northwest IA through
the end of the period. Otherwise strong southerly winds may gust to
30 to 40 mph this morning, then gradually taper off through the
afternoon. Outside of any thunderstorms, VFR conditions are
expected.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...08
AVIATION...08