605
FXUS63 KFSD 072320
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
620 PM CDT Tue May 7 2024

.KEY MESSAGES...

- Shower and storm chances return on Wednesday. Some storms
  could be strong to severe and bring another round of meaningful
  rainfall. Locations along and east of I-29 have the highest
  probability (30- 50% chance) for exceeding a half an inch of
  rain.

- Warmer and mainly dry conditions move in for the weekend and
  into early next week.

&&

.DISCUSSION...
Issued at 313 PM CDT Tue May 7 2024

Vertically stacked low pressure systems continues to spin over the
North Dakota and South Dakota border this afternoon. This has
resulted in west/southwest winds across the area with gusts between
30 to 45 mph, strongest along and west of the James River. A Wind
Advisory remains in effect through 7 pm this evening for this area.
Sprinkles to light showers remain possible under the diurnally
driven strato-cumulus field. Winds along with any chance for rain
will wane this evening and the boundary layer stabilizes. Low
temperatures will fall to the 40s overnight.

The upper level low wobbles over part of the forecast area tomorrow,
brining another chance for showers and storms. An occluded front
looks to set up east of I-29 tomorrow afternoon. Destabilization
looks to briefly occur early tomorrow afternoon where CAPE values
may max out around 1,000 J/kg. However, dry air in the low levels
will allow for stronger mixing to occur which could mix out the
instability to some degree. The strong mixing will allow for high
temperatures to warm up to the 60s tomorrow afternoon. With a deep
mixed layer and some instability along the front, thunderstorms look
to develop. Where storms develop remains a bit uncertain at this
time as hi-res guidance varies on how far north or south the
boundary sets up. Given the vorticity along the boundary along with
dry low levels, think cold air funnels along with damaging winds up
to 60 mph are the primary hazards with the storms that do develop.
Sufficient shear is present as well but will be on a decreasing
trend as the upper low moves overhead. This will present an isolated
hail risk to hail up to the size of half dollars but this will be
the secondary risk.

The other aspect to tomorrows storms is another round of meaningful
rainfall. Difficult to say how much rain will fall in any one
particular location or area as hi-res guidance varies significantly
in where convection develops. However, latest HREF probabilities
show a 30-50% chance for locations east of I-29 receiving a half an
inch of rain. The additional rainfall may lead to ponding on
roadways and minor flooding in rivers and streams. Low temperatures
will fall to 40s overnight.

Broad upper level troughing persists across the Northern Plains for
the rest of the work week and weekend. With a northwest flow regime
in place due to the troughing, dry conditions are expected to
prevail. High temperatures will warm to the 60s, 70s, and
potentially reaching up to about 80 degrees F on Sunday. The GFS and
Canadian ensembles support this possibility as they show a 30-50+%
chance for exceeding 80 degrees F. The Euro ensemble is the outlier
as it shows a near zero probability for exceeding 80 degree F
temperatures.

Another trough looks to push into the Northern Plains early next
week as ensembles are consistent with this potential. This trough
may also bring renewed rain potential but details remain uncertain
at this time. Aside from rain potential, highs look to remain in the
70s with lows in the 50s.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 619 PM CDT Tue May 7 2024

VFR conditions are forecast to prevail this TAF cycle. Should see
breezy W/SW quickly diminish after sunset, with light and variable
conditions expected to persist through the overnight period.
Otherwise, look for winds to pick pick up a bit after daybreak, with
direction still remaining variable as upper level low moves
overhead. A few showers may be possible during the
afternoon/evening, which may result in periods of reduced
cigs/vsbys.

&&

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

&&

$$

DISCUSSION...Meyers
AVIATION...SST