425
FXUS63 KFSD 051057
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
557 AM CDT Sun May 5 2024

.KEY MESSAGES...

- Conditions will continue to trend warmer into the early part
  of the week with highs returning to upper 60s and low 70s for
  today and Monday.

- Winds may near advisory levels on Monday afternoon in areas
  along and west of I-29.

- A few strong to severe storms will be possible Monday
  afternoon and evening, with the greatest severe threat
  currently focused along and south of the lower Missouri River
  corridor into parts of northwestern IA.

- Periodic rain chances continue for much of the upcoming week,
  with highs in the 60s to lower 70s.

&&

.DISCUSSION...
Issued at 400 AM CDT Sun May 5 2024

Look for a pretty decent day ahead as surface high pressure
continues to exert its influence across the region. While the surface
ridge axis is located directly over our area this morning, it will
shift eastward during the day - into the Mississippi Valley by this
evening. Winds will be southerly in a weak warm air advection regime
on the backside of the high, and this will result in warmer
temperatures for today. With 850 mb temperatures of 7 to 10 degrees
across the area, look for highs in the upper 60s to lower 70s. A
deepening surface trough over eastern MT and WY will result in an
increasing surface pressure gradient (SPG) across our area, and this
will result in increasing winds by the afternoon. This will be most
pronounced west of Interstate 29 where the SPG is tighter and winds
at the top of the mixed layer are higher.

Tonight will see an increase in cloudiness - this as the
aforementioned surface trough continues to deepen and shift into
western SD, as an upper level low moves out of the Four Corners
region into eastern WY and CO overnight. As the SPG continues to
tighten over our area, winds will remain breezy during the night
time hours. With the breezy conditions and warm air advection, it
will be a mild night for this time of year with lows in the upper
40s to lower 50s.

The upper level low lifts through western NE and western SD/ND on
Monday and Monday night, while the surface low shifts northward
through the western Dakotas - pulling a warm front northward across
the region. With that, showers and thunderstorms will return to our
area for Monday and Monday night. There remains a potential for
strong to severe storms over the area on Monday afternoon/evening -
as outlined in the SPC Day 2 convective outlook (a Slight risk
[level 2 of 5] through the lower MO River Valley/northeast NE/parts
of northwest IA and a Marginal risk [level 1 of 5] north to around
the I-90 corridor). There are caveats however, with most models
indicating instability on the lower side - generally less than 1000
J/KG. At the same time, ensembles continue with low probabilities of
CAPE greater than 1000 J/KG - at only 10-20% over our area. The
latest CSU machine learning probabilities are on the lower side
for severe weather, with CIPS analog probabilities also on the
lower side - 10-15%. There is however plenty of 0-6 bulk shear
(around 40-50 kts) with strong winds through the low to mid
levels. So in summary, while this in not a slam dunk for severe
weather in our area, cannot rule out the potential for at least
a few stronger storms. Related, with the strong winds aloft, it
will be a windy day with sustained winds of 20-30 mph and gusts
of 40 to 45 mph. It will be a relatively warm day with highs in
the upper 60s to lower 70s. Any storms on Monday will exit our
area very early Tuesday morning. We could again see moderate to
heavy rain with the system, with latest ensembles indicating
around a 70% probability of receiving at least half an inch of
rain.

For Tuesday through Friday, small to moderate (20-50%) rain chances
linger through the period. This as the aforementioned upper level low
rotates back to the northwest into the northern Rockies on Tuesday,
then back into the Northern Plains on Wednesday. It then only slowly
shifts to the east on Thursday and Friday, with perhaps a drying
trend toward next weekend. Highs through the period will be mainly
in the 60s with lows in the 40s. It looks to be a breezy each day.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 550 AM CDT Sun May 5 2024

VFR conditions expected through the TAF period. Southeasterly
winds will increase through the morning, gusting around 20 to 25
kts into tonight. As a low level jet develops over central SD,
LLWS will develop at KHON later tonight.

&&

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

&&

$$

DISCUSSION...JM
AVIATION...JM