012
FXUS63 KFSD 011952
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
252 PM CDT Mon Jul 1 2024

.KEY MESSAGES...

- Below normal temperatures continue through most of the week
  with high temperatures on the order of near seasonable to 5 to
  10 degrees below average.

- Severe weather remains possible this evening, with hail to
  the size of ping pong balls and damaging winds up to 60 MPH
  expected to be the primary hazards.

- Heavy rain also remains possible tonight through Tuesday
  morning. Those along and southeast of a line extending from
  Tyndall/Sioux Falls/Marshall could see anywhere from a tenth
  to 1.5 inches. Locally higher amounts (2 to 3 inches) may
  still occur, especially in the presence of training storms.
  Thus, a Flood Watch has been issued for portions of our area.

- Active weather pattern aloft supports periodic chances for
  showers and storms for the remainder of the week, with a brief
  lull possible Wednesday.

&&

.DISCUSSION...
Issued at 251 PM CDT Mon Jul 1 2024

CURRENT THROUGH TONIGHT: Scattered showers and storms remain ongoing
across the region, with latest observations showing mostly cloudy
skies and temperatures in the mid to upper 60s. Broad WAA and an
increasing LLJ have also resulted in fairly breezy southeasterly
winds across our area, with gusts currently ranging between 25 to 45
MPH. Expect much of the same throughout the afternoon, with gusts
lessening to 15-25 MPH near sunset.

Heading into the evening, our attention turns to an advancing upper
level wave progged to push eastward across the Northern Plains. Have
already noted dewpoints in the lower 60s as far north as the MO
River Valley ahead of an advancing sfc warm front. Given the
efficient moisture transport in place, expect showers and storms to
redevelop near/shortly after sunset in areas west of the James
River. While a few of these storms could become strong to severe,
expect this initial wave to fizzle out as they push eastward into
dry/stable air near the sfc. Better chances for severe weather looks
to occur along the MO River Valley and along/south of Highway 18
between 00-06Z. While a few discrete storms may be possible
initially, expect storms to favor a linear storm mode - with ping
pong ball size hail and gusts up to 60 MPH being the primary hazards.

In addition to severe weather, also want to emphasis that heavy rain
will also be possible, especially with PWATs near/exceeding 2
inches. While there has been a slight decrease in rainfall totals
through Tuesday morning, still expect amounts to range between a
tenth to 1.5 inches along and southeast of a line from Tyndall/Sioux
Falls/Marshall. That being said, could still see pockets of locally
higher amounts (2 to 3 inches) occur, especially in the presence of
training storms. Thus, given the recent rains and saturated soils in
place, have decided alongside neighbors to issue a Flood Watch for
portions of our area, which will be in effect from 7 PM tonight
through 7 AM Tuesday. As always, we encourage you to have a way to
receive warnings. In the meantime, be sure to clear gutters and
street drains of all debris and make sure your sump pump is working.
And remember, if you encounter a flooded roadway - turn around,
don`t drown!

TUESDAY AND WEDNESDAY: Sfc cold front dives across the region
Tuesday in the wake of the aforementioned upper level wave. A bit of
uncertainty still exist concerning how quickly this boundary will
advance across our area, which will in turn effect the odds of
seeing strong to severe storms. Latest CAMs would suggest a quicker
solution, thus, keeping the threat for severe weather largely
southeast of our area. However, if the cold front advances slower
than expected, can`t rule out the possibility of seeing a few strong
to severe storms across NW Iowa. Will continue to monitor trends in
the meantime. Otherwise, look for afternoon highs to rise into the
upper 70s to lower 80s.

Should see dry conditions return late Tuesday night and continue for
much of the day Wednesday as sfc ridging slides overhead. 850 mb
temperatures will warm to the upper teens which will result in
seasonable high temperatures in the low to mid 80s. Lows during this
time will also remain fairly mild, as temperatures only fall into
the lower 60s.

WEDNESDAY NIGHT AND BEYOND: Precipitation chances return to the
forecast Wednesday evening as yet another upper level wave takes aim
at the region. While some fluctuations in timing may still occur,
expect showers and storms to be possible late Wednesday through
Thursday afternoon. As alluded to in the previous discussion,
ensembles continue to show high probabilities (near 100%) for
exceeding a tenth of an inch of rain. However, their probabilities
drop to about 30-50% for exceeding a half an inch of rain, with the
higher amounts generally across south-central South Dakota. Will
certainly need to keep an eye on things in the coming days, as it
will not take much rainfall to cause additional flooding concerns.

Periodic chances for showers and storms continue for the remainder
of the week as an active weather pattern lingers aloft. Temperatures
look to be a touch cooler Thursday and Friday, with highs largely in
the 70s and lows in the upper 50s. Drier conditions could make a
return this weekend as upper level ridging builds into the western
CONUS but too early to say if any ridge riding waves will bring
continued chances for rain to the area.


&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1243 PM CDT Mon Jul 1 2024

Scattered showers and storms continue across the region resulting in
MVFR to VFR levels. Should see a brief lull in activity this
afternoon, with additional development possible this evening. As
alluded to in the previous discussion, confidence is highest in
locations along and southeast of a line from Tyndall/Sioux
Falls/Slayton. A few storms could become strong to severe, with hail
and damaging winds being the primary hazards. For now, have only
included mention of thunder at KSUX. Will continue to monitor trends
and adjust other sites as needed. Cigs during this time look to fall
to IFR levels, though brief period of LIFR may still occur.
Otherwise, expect breezy southeasterly winds to weaken after sunset.

Cold front dives across the region Tuesday, causing winds to shift
to the northwest. Another round of precipitation will also be
possible, though this will largely depend on how quickly the front
advances across our area.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Flood Watch from 7 PM CDT this evening through Tuesday morning
     for SDZ070-071.
MN...None.
IA...Flood Watch from 7 PM CDT this evening through Tuesday morning
     for IAZ012>014-020>022-031-032.
NE...Flood Watch from 7 PM CDT this evening through Tuesday morning
     for NEZ013-014.

&&

$$

DISCUSSION...SST
AVIATION...SST