Severe Thunderstorm Warning 83, NWS Sioux Falls, SD

384 
WWUS53 KFSD 102031
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
331 PM CDT Mon Jul 10 2023

SDC009-135-102045-
/O.CON.KFSD.SV.W.0083.000000T0000Z-230710T2045Z/
Bon Homme SD-Yankton SD-
331 PM CDT Mon Jul 10 2023

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM CDT
FOR EAST CENTRAL BON HOMME AND SOUTHWESTERN YANKTON COUNTIES...

At 331 PM CDT, a severe thunderstorm was located near Tabor, or near
Lewis And Clark State Recreation Area, moving southeast at 20 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
  Lewis And Clark State Recreation Area and Yankton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4291 9776 4303 9768 4290 9735 4286 9739
      4287 9741 4285 9744 4286 9750 4285 9758
      4286 9762 4284 9769 4284 9770
TIME...MOT...LOC 2031Z 306DEG 19KT 4290 9765 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

AP

368 
WWUS53 KFSD 102046
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
346 PM CDT Mon Jul 10 2023

SDC009-135-102056-
/O.EXP.KFSD.SV.W.0083.000000T0000Z-230710T2045Z/
Bon Homme SD-Yankton SD-
346 PM CDT Mon Jul 10 2023

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL BON HOMME AND
SOUTHWESTERN YANKTON COUNTIES HAS EXPIRED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been allowed to expire.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
southeastern South Dakota.

LAT...LON 4291 9776 4303 9768 4290 9735 4286 9739
      4287 9741 4285 9744 4286 9750 4285 9758
      4286 9762 4284 9769 4284 9770
TIME...MOT...LOC 2045Z 306DEG 19KT 4286 9757 

$$

AP

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1242 PM CDT Mon Jul 10 2023

.SHORT TERM...(Today and Tonight)
Issued at 409 AM CDT Mon Jul 10 2023

Broad weak warm air advection with a southwest breeze has kept
temperatures in the 60s early this morning with a few typical cooler
spots dipping to the upper 50s. Abundant sunshine and efficient
mixing will kick temperatures into the 80s across the region by mid
day. Summer heat and more humid conditions make a comeback today
with highs expected to reach well into the 80s east of I-29 and the
90s near and west of the I-29 corridor. A southwest breeze will
provide a bit of relief from the heat, as well as unstable cumulus
developing this afternoon.

By early afternoon, a west-to-east oriented prefrontal sfc trough
develops near the Hwy 14 corridor with mid 60s to near 70s dew
points pooling south of the I-90 corridor as the trough sags south.
Moderate instability of 1500-2000 J/kg couples with increasing 0-6km
effective shear (30-40 kts) to set the stage for severe weather
threat late this afternoon through early evening. By mid afternoon,
much of the region should reach convective temperatures with capping
disintegrating. The Euro/NAM show potential for isolated strong to
severe storms to develop near or east of the James River Valley in
southeast South Dakota or even potentially parts of southwest
Minnesota mid afternoon, aided by ascent from a weak mid level wave
and upper jet nosing in from the northwest. Increased pops in this
area to account for latest Euro/NAM/HRRR solutions that support
this, given these are the models performing better with current
(higher) dew points in the upper 50s to lower 60s.

Late in the afternoon, attention turns more to south of I-90 and
especially near the Nebraska/South Dakota/Iowa tri-state area and
U.S. Hwy 20 area where the threat for isolated to scattered
supercells is highest (i.e., via strongest destabilization and
deep layer shear). Inverted V soundings and DCAPE of 1400-2000
J/kg suggest potential for damaging wind gusts up to 70 mph, and
storm mode coupled with mid level lapse rates of 6.5-7.5 C/km
supports up to golf ball sized hail (or perhaps even larger, via
analog soundings). There is also a low threat for a tornado or two
if sfc winds can locally alter to more of a southeast (instead of
southwest) direction. Threats are similar both north and south of
the I-90 corridor, but HREF updraft helicity tracks signal the
greater coverage (scattered vs very isolated) and severity of the
threat will be south of I-90. Storms will track mainly
southeasterly, likely exiting southward by 8 to 10 PM.
Precipitable water values exceeding one inch favor pockets of
heavy downpours with stronger storms as well.

Behind this activity, a trailing cold front brings in drier low
level air and shifts winds northward overnight. Expect temperatures
to fall into the 50s (north under clearer skies) to lower 60s (south
where clouds and higher moisture content linger) overnight.

.LONG TERM...(Tuesday through Sunday)
Issued at 409 AM CDT Mon Jul 10 2023

TUESDAY: Monday's front sags to somewhere in the vicinity from the
Hwy 20 corridor to the I-80 corridor by Tuesday morning, bringing a
cool start to the day. Below normal temperatures persist Tuesday
behind the front with drier, light northeast winds. May see
scattered high based showers during the day

The now quasi-stationary front (to our south) will extend back
northwest through the High Plains, ahead of another strong wave
ejecting from the Rockies late Tuesday. This becomes the focus for
convection in the High Plains Tuesday afternoon and evening, which
will gradually track southeast along the instability gradient
through the evening.

While isolated elevated convective development remains possible
Tuesday afternoon west of I-29, the better rain chance develops
Tuesday night. 00z models are still split into two camps: 1) the
nocturnal low level jet aids MCS development in the High Plains,
likely tracking an MCS with severe threat to our south with heavy
rain threat the greatest south of the I-90 corridor and 2)
convection develops in eastern SD Tuesday mid to late evening and
merges into an MCS, bringing severe wx (hail and wind) threat and
heavy rain threat Tuesday night across the forecast area. While
ensemble guidance would continue to favor the first solution, cannot
entirely discount the 2nd/worse case scenario just yet. Ensemble
guidance continues to support a 60-80% chance of a widespread 0.25
inches of rain with deterministic guidance favoring pockets of
downpours producing 2+ inches of rain. The heaviest rain is still
favored to occur south of the I-90 corridor (again favoring the
first, more likely solution), but the location could range from near
the Sioux City metro to near the Omaha metro.

WEDNESDAY THROUGH FRIDAY: Confidence decreases in the forecast late
week with periods of low chances for showers and storms as weak
waves track through in northwest flow aloft. Wednesday should start
off mainly dry and cool again, but another mid level wave trailing
through the Northern Plains poses a low chance for another round of
isolated storms to develop with nonzero severe weather potential.
This similar pattern continues through at least Friday with low
evening/night storm chances depending on where weak disturbances
track in northwest flow aloft.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 1242 PM CDT Mon Jul 10 2023

VFR conditions expected at KHON/KFSD over the next 24 hours with
the primary impact to aviation operations being a wind shift from
the west-southwest to the north-northeast with some gusts up to 20
kts as a cold front drops south across the region. A few -TSRA
could develop along the front, but coverage is expected to be very
limited, so will not include any mention at this time. Toward the
end of the period, there could be some decaying showers and
thunderstorms from overnight convection across western SD, but
timing/coverage uncertainty precludes mention in the 10.18Z TAF.

For KSUX, better chances for -TSRA exist from late this afternoon
into the early evening along a pre-frontal surface boundary.
Introduced a TEMPO group for this possibility from 10.22Z-11.02Z,
but coverage may still be more scattered in nature and updates are
likely. MVFR/IFR conditions possible if a thunderstorm moves over
the airfield. In addition, any thunderstorm has the potential to
produce damaging wind gusts and/or hail. For now, will not include
higher end potential impacts in TAF. Away from thunderstorms, VFR
conditions will also be the rule at KSUX with surface winds
shifting to the north-northeast late this evening with eventual
passage of the cold front.

&&

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

SHORT TERM...BP
LONG TERM...BP
AVIATION...Rogers

Hazardous Weather Outlook
National Weather Service Sioux Falls SD
127 PM CDT Mon Jul 10 2023

IAZ001>003-MNZ071-072-080-081-089-090-097-098-SDZ038>040-050-
052>065-111830-
Lyon-Osceola-Dickinson-Lincoln-Murray-Cottonwood-Nobles-Jackson-
Pipestone-Rock-Beadle-Kingsbury-Brookings-Gregory-Jerauld-Sanborn-
Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook-Minnehaha-
Charles Mix-Douglas-Hutchinson-
127 PM CDT Mon Jul 10 2023

This Hazardous Weather Outlook is for portions of northwest Iowa,
southwest Minnesota, central South Dakota, east central South
Dakota, south central South Dakota, and southeast South Dakota.

.DAY ONE...This Afternoon and Tonight

Isolated strong to severe thunderstorms are possible mid afternoon
through mid evening. Large hail up to ping pong ball size and
damaging wind gusts up to 65 mph are the main threats with the
strongest storms.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Showers and thunderstorms are expected to spread through on Tuesday
night, bringing a threat for isolated severe thunderstorms with large
hail and damaging winds, as well as pockets of heavy downpours.

Periods of low chances for showers and thunderstorms continue
Wednesday afternoon through Friday, but confidence in any details is
low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

IAZ012>014-020>022-031-032-NEZ013-014-SDZ066>071-111830-
Sioux-O'Brien-Clay-Plymouth-Cherokee-Buena Vista-Woodbury-Ida-
Dixon-Dakota-Turner-Lincoln-Bon Homme-Yankton-Union-
127 PM CDT Mon Jul 10 2023

This Hazardous Weather Outlook is for portions of northwest Iowa,
west central Iowa, northeast Nebraska, and southeast South
Dakota.

.DAY ONE...This Afternoon and Tonight

Isolated to scattered strong to severe thunderstorms are likely
late this afternoon through early this evening. Hail up to ping
pong ball size, damaging wind gusts up to 75 mph, heavy
downpours, and an isolated tornado or two are the main threats
with the strongest storms.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Showers and thunderstorms are expected to spread through on Tuesday
night into early Wednesday, bringing a threat for isolated severe
thunderstorms with large hail and damaging winds and pockets of
locally heavy downpours.

Periods of low chances for showers and thunderstorms continue
Wednesday afternoon through Friday, but confidence in any details is
low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.